NEW ZEALAND

DEPARTMENT OF SCIENTIFIC AND INDUSTRIAL RESEARCH

M. FIELDES DIRECTOR

SOIL BUREAU BULLETIN 26(1)

SOILS OF NEW ZEALAND PART 1

By the staff of Soil Bureau, New Zealand Department of Scientific and Industrial Research

with contributions from members of

Plant Diseases Division, Department of Scientific and Industrial Research; Extension

Division, Department of Agriculture; New Zealand Forest Service; Town and Country

Planning Branch, Ministry of Works; and Lincoln College, University of Canterbury.

19 6 8

A. R. SHEARER, GOVERNMENT PRINTER, WELLINGTON, NEW ZEALAND

Price: $5.50 Editor, Jean Luke Information Service, D.S.I.R.

assisted by

Janice Heine, Soil Bureau

Bibliographic Reference:

N.Z. Soil Bureau 1968: Soils of New Zealand. Part 1.

N.Z. Soil Bur. Bull. 26(1).

@ Crown Copyright 1968

Printed by Whitcombe and Tombs Limited, Christchurch

Under authority A.. R. Shearer, Government Printer, Wellington, New Zealand-1968 SOILS OF NEW ZEALAND

PART 1 Photo, R. Julian

FRONTISPIECE: Taita Experimental Station of Soil Bureau, D.S.I.R., consisting of some 200 acres, is situated on the eastern foothills of the Hutt part Station-the (on left) forest (on hill in Valley. Only of the exotic catchment the and the native catchment the central slopes)--is seen this College grounds). photograph. The headquarters of Soil Bureau are in the middle foreground (behind Taita and FOREWORD

New Zealand is essentially an agricultural country. Ninety-five per cent of our export income is derived from products of the soil and, with existing trends in population, the Targets Committee of the Agricultural Development Conference production estimates that farm must be increased at an average annual rate of 3 *8 per cent to maintain present standards of living. Soil science has played a vital role in increasing farm production in New Zealand in the past. For example, the correction of deficiencies of both major and minor elements has extended the area that can be profitably farmed, e.g. cobalt deficiency, and has greatly increased yields. To meet the targets for increased exports our soil resources must be used more intensively than in the past, and this will call for more basic research into their properties as a medium for increased pasture and crop production.

Different parts of the New Zealand sector have widely differing climatic con- ditions ranging from subantarctic to subtropical, with rainfalls of 12 to 300 inches per annum; this, together with the diversity of parent material, vegetation, and topography, results in a very wide array of soils. Because of the small size of New Zealand (103,000 square miles) it is possible for one man to be familiar at first hand with a range of soils not always encompassed within a continent. This makes it easier to study relations between many different kinds of soil, and the correlations thus established can be of value in interpreting soils in other countries where larger distances make relationships less obvious.

This comprehensive bulletin states the basis of New Zealand soil classification, provides precise, detailed information from the main soil disciplines upon a. wide range of New Zealand soils, and relates these data to the soil classification. The results of many aspects of soil research within D.S.I.R. are thus made available as a basis for advisory work and for future soil and agricultural research.

No compilation such as this can be more than an interim interpretation in the light of present knowledge. It is not an end in itself but a stocktaking to prepare for new advances. W. M. HAMILTON, Director-General,

Department of Scientific and Industrial Research 25 January, 1968

3 CONTENTS

Page FOREWORD 3 * * * * * * - * - * PREFACE 6 * - * * - - - - * -

CHAPTER 1. The Soil Environment (by N. H. Taylor and I. J. Pohlen) 1-1*Introduction- * * * * * * *7 1*2* Geology and Topography 7 - - - * * * - - 1-3- Climate 10 * * - - - * * * * * 1-4* Vegetation 11 * * - - * * - * * * 1*5* Age of the Soils 14 * * - * * * - * * 1-6* References 14 * - * * * * * - *

CHAPTER 2. Classification of New Zealand Soils (by N. H. Taylor and I. J. Pohlen) 2-1* Introduction 15 ------* * - 2-2* Soil Formation 15 * * * * * Wasting Regime 16 * * * * * - * * * Organic Regime 17 - - - * * - - * Drift Regime 19 - * * * * * * * * 2-3- Principles and Criteria of Genetic Classification 20 - - - - Category I-Basal Forms 20 - * - * * - - Category II-Main Energy Status 22 * - - - - - Category III-(a) Argillisation or (b) The Counter Processes of Accumulation, Removal, and Mixing 23 * * - - - - Category IV-Horizon Development 27 ------Category V-State of Enleaching 28 - - - - - * Category VI-Parent Material 28 ------Category VII-Surface or Subsoil Horizons 28 - - - - - Derivation of Terms 29 - - * * * - * * 2-4- Genetic Names 29 * * - * * * * * 2-5* The Classification Zonally Arranged 30 - * * * - 2-6- Use ofSoil-Moisture Classes in Phasic Subdivisions 32 - - - - Dry Classes 32 * * * * - - - - * Moist Classes 32 * ------2-7- Evaluation of Climate and its Correlation with Soil Groups (by J. E. Cox) 33 - * Elements of Thornthwaite’s Classification (1948) 33 - - - - Proposed Grouping of Climate Stations into Climatic Classes 35 * - - Soils Associated with the Climatic Classes 35 * - * - - Acknowledgment 35 - - - * * - - - 2-8- Provisional Classification of Soil Clays for Use in Phasing Soils (by M. Fieldes) 45 * 2-9* References 45 * * * * * * * * * *

CHAPTER 3. Regional Description of New Zealand Soils

3*1* General Introduction (by H. S. Gibbs) 47 * * * - * * 3*2* Soils of North Island (by H. S. Gibbs, J. D. Cowie, W. A. Pidlar) 48 - * - Taupo Bay of Plenty 48 - * - * - * - - - Taranaki Wanganui 52 - - * - - - - * * Manawatu Wellington 54 ------* Wairarapa Gisborne 57 - - * - * - * * - South Auckland 60 - * ------North Auckland 63 - - - * - - - - - 3-3* Soils of South Island (by J. D. Raeside, C. G. Vucetich, J. E. Cox, J. D. McCraw, M. L. Leamy, E. J. B. Cutler, and H. S. Gibbs) 67 - * - - - North-eastern Region 67 * - - * - * * * Western Region 72 * - - * - - - * - Central Region 75 * - - * - - - - - Eastern Region 79 - - * * - - * - - Southern Region 83 - - - - * * * * 3-4-Bibliography * * * * * - * -87 -

4 CHAPTER 4. Soils and Land Use

4 1 General Pattern of Soils and Land Use (by N. H. Taylor, I. J. Pohlen, and R. H. Scott) 89 - - Zonal Soils 89 ------* - Intrazonal and Azonal Soils 93 - - * * 4-2- Forestry (by A. L. Poole) 96 - - - - New Zealand as a Tree-growing Country 96 - - - - - Mountainous Areas 97 * - * - - - - - Lowland and Montane Areas 98 ------4-3- The Growth of Ryegrass and White Clover on Untopdressed Soils under Glasshouse Conditions (by J. P. Widdowson and N. Wells) 99 * - - - - Introduction 99 ------Ryegrass 100 ------* White Clover 100 ------Plant Growth in Relation to Soil Chemistry 101 - - - - - Growth Values in Relation Site Vegetation 101 to * - - - - Growth Values in Relation Soil Classification 103 to - - - - - Acknowledgments 104 - - - * * - - - 4-4- Changes Induced in the Soil by Pastoral Farming (by T. W. Walker) 104 - - Introduction 104 * * * * * - - - - Ecology of Grass Clover Associations 105 ------Nutrient Requirements of Grass Clover Associations 105 - - - - - Induced Soil Changes 106 ------Unimproved Areas 109 ------* References 109 - - - - - * - - - 4-5* Some Soil Plant Animal Relationships (by W. B. Healy) 110 * * * * - - 4-6* Soil Erosion and Conservation (by H. S. Gibbs, J.D. Raeside, E. J. B. Cutler, and W. A. Pullar) 112 * ------Introduction 112 * * * - - - * * * Soil Erosion According Soil Groups 113 to - - * - - - Soil Erosion and Community 118 the ------References 118 * * * - - - * * - 4-7- Town and Country Planning (by J. W. Cox) 119 - - * - Introduction 119 ------Early Development 119 - - * * * * * * Urban Industry and Population Expansion 119 * - - - - Town and Country Planning Act 120 * * * * * *

CHAPTER 5. Soil Classification for Land Use (by H. S. Gibbs)

5 I Introduction 124 - - - - - * - 5-2- Purposes of Classification 125 * - - - * - 5 3 Classification for Pastoral Farming 125 - - - - - * - 5-4- Soil Limitations for Pastoral Farming 127 * - - 5 5 Potential Pastoral Capacity 129 * - - - - - * - 5 6 References 130 - - * * * * * * * *

GLOSSARY OF PLANT NAMES USED IN THE TEXT 131 - * - GENERAL INDEX 133 - - - SOILS INDEX 137 - * - * CONTENTS OF PARTS 2 3 141 and * * - - - -

MAPS (in pocket)

Soil Map of the North Island, New Zealand. I : 1,000,000. (1963) (1963) Soil Map of the South Island, New Zealand. 1 : 1,000,000. Map of the North Island, New Zealand, Showing Soil Classes for Potential Pastoral Use. I : 1,000,000. (1964)

Map of the South Island, New Zealand, Showing Soil Classes for Potential Pastoral Use. 1 : 1,000,000. (1965)

5 PREFACE

New Zealand, for its size, has an unusually wide in mimeographed form to overseas delegates to the range of soil-forming factors. It is so situated in the Joint Meeting in New Zealand of Commissions Pacific that within its length of a thousand miles IV and V of. the International Society of Soil the climate ranges from subtropical to mild tem- Science in 1962, when there was opportunity for perate and subalpine, and from superhumid to international scrutiny and discussion in the field semi-arid; the topography ranges from the flat during the tours associated with that meeting. surfaces of extensive plains to the steep slopes of Suitable authors agreed to write different sections the high mountains; the vegetation from mull of the text. They included specialists from the formers to extreme mor formers; and the parent Department of Agriculture, Forest Service, Ministry rocks of the soils from siliceous to calcareous of Works, Lincoln College, and Plant Diseases sedimentary rocks and from rhyolitic pumice ash Division of D.S.I.R. They drew, as required, both to massive ultrabasic igneous rocks. The time of upon the definitive results mentioned above and soil formation also ranges widely, very young soils upon general results of earlier work. During sub- formed being formed on recent deposits and well developed sequent integration, conclusions -were and soils on surfaces of considerable age that have tested as far as possible by precise reference to the escaped major effects of glaciation. definitive data. In the course of preparation of the The resulting soils, which have a wide variety of full text, which occupied a number of years, im- properties, have been the subject of considerable provements in soil classification occurred, and investigation for the purpose of ensuring their where in places for practical reasons these have proper use. Consequently much scientific informa- not been fully incorporated in the text they have tion concerning them has accumulated particularly been indicated by suitable cross references. in recent decades. In 1959 it was decided that it was Authors of the various sections are named in the timely to bring together existing basic knowledge text, but many others contributed in the preparation of New Zealand soils in book form suitable for the and presentation of the data. Hence the published student and for users of soil information engaged work represents a contribution by the Soil Bureau in agriculture, forestry, engineering, and other and its collaborators as a whole. It is presented in specialised fields involved in land utilisation. three volumes, Part 1 (Chapters 1-5) containing Although within Soil Bureau in 1959 knowledge principles of soil classification and general descrip- of main soil groups was extensive, much of the data tions of soil and land use patterns, Part 2 (Chapters available had been obtained over a period of years 6-10) consisting of accounts of the significance of by different workers using varying methods on mineralogical, chemical, physical, engineering, and materials from different sites. Data of this descrip- biological properties of New Zealand soils, and tion were not satisfactory for scientific correlation Part 3 (Chapter 11) with descriptions of the of soil properties, and, as a step towards more reference soils and their analytical data. definitive correlation, 54 reference sites were chosen The work was initiated by Dr N. H. Taylor on soils representing a wide range of the main soil (Director of Soil Bureau from 1954 to 1962) and groups of New Zealand. The reference soils from continued under Dr J. K. Dixon (Director from these sites were examined and described by workers 1962 to 1966). Mr I. J. Pohlen assisted in the later in the different scientific disciplines using, as far as stages with detailed scientific editing of the complete possible, uniform, standardised, up-to-date methods text. Miss Jean Luke, of the Information Service, throughout. The results so obtained are for the D.S.I.R., with the assistance of Mrs Janice Heine most part tabulated in Part 3. They were available in Soil Bureau, was responsible for fmal editing.

M. FIELDES, Director, 25 January, 1968 Soil Bureau, D.S.I.R.

6 I

CHAPTER 1. THE SOL ENVIRONMENT

by N. H. TAYLOR and I. J. POHLEN

1-1- INTRODUCTION

Soil is the product of its environment-of the the soils were formed ranged, in more humid rock waste that is its parent material, of the climate areas, from kauri forests in the north, to mixed under which it is formed, of the kind of topography podocarp-broadleaved forest and beech forest fur- upon which it is situated, of the organisms (nota- ther south, with subalpine scrub and fellfield in bly the vegetation) that have modified it, and of more elevated situations; in the drier areas tussock the length of time during which it has been develop- grassland was the dominant vegetation. ing. The soil pattern in New Zealand is complex, The underlying rocks are varied in texture and owing not only to the many different kinds of composition. They include igneous rocks (which rocks but also to the varied conditions under range from ultrabasic to acidic), metamorphic which they have been transformed into soil. rocks, and sedimentary rocks (conglomerates, sand- New Zealand proper (the main islands) is about stones, mudstones, and limestones). In the north in 1,000 miles long and embraces such extremes as of New Zealand many soils are old, but the young, subtropical Northland, the cold uplands of the south most are relatively the old soils during alpine regions, the semi-arid basins of Central having been almost everywhere destroyed places, however, Otago, and the very wet mountains and lowlands the Ice Age. In many events such plains, of Westland. The topography is varied; approxi- as the flooding of rivers over alluvial the mately half of New Zealand is steep, a fifth is drifting of sand and dust, and the fall of ash from moderately hilly, and less than a third is either erupting volcanoes have interrupted soil develop- rolling or ilat. The natural vegetation under which ment.

1*2* GEOLOGY AND TOPOGRAPHY

Westland New Zealand rises from two main submarine Stewart Island through Fiordiand and has ridges, which extend north-westward to New to north-west Nelson. This old foreland two New prominent Fiordland and north-west Caledonia and Guinea and north-eastward -buttresses, towards Tonga. It lies on the margin of the Pacific Nelson. Basin at the edge of the Asiatic-Australian con- Fiordland is an extremely rugged terrain rising in tinental belt in a zone of long-continued structural to some 4,000 ft in the south and 8,000 ft the by glaciated instability where persistent tectonic activity has north and is deeply dissected valleys lakes led to both stratigraphic complexity and recurring that open into flords on the west and of largely vulcanism. It displays well the landforms due to glacial origin on the east. It is composed of gneiss, granite, folded, late tectonic movements and in this respect re- diorite, and and strongly sembles other countries of the mobile Pacific indurated conglomerates, sandstones, shales, and part Nelson is margin, which differ from the old and stable parts marbles. The greater of north-west 3,000 ft of the earth-the interiors of continents-where steep land lying above and rising to some granites, grey- the landforms are almost wholly due to erosion 6,000 ft. The rocks are mainly old (Fleming, 1959). wackes, and marbles, with lesser areas of Tertiary The distribution of the wide variety of New sandstones and mudstones. for Zealand rocks, representing almost every geo- The greywackes, argillites, and schists are Paleozoic in logical period since the Precambrian, is summarised the most part Mesozoic and Upper by Shaw (1959) and Grindley et al. (1959). The age. They form the core of New Zealand and are oldest rocks (Precambrian and Lower Paleozoic) the rocks of the north-easterly trending axial from South- are found in a western belt that extends from ranges, which dominate the landscape

7 1-2 land to East Cape and owe their origin to the ranges west of Auckland, in Coromandel Penin- mountain-building movements of Tertiary and sula, on Great Barrier and Little Barrier Islands, Pleistocene time, movements that are still in pro- near Cape Runaway, and south-west of Hamilton. gress. The younger rocks, mainly olivine basalts of In the South Island the alpine mountain chain Pleistocene and Recent age, are confined mainly reaches its maximum elevation (12,349 ft) in the to Auckland and North Auckland, where the middle of the Southern Alps, but on the east and flows are relatively 11at and are associated with north the mountain crests mostly lie between cones of scoria and lava. Andesites and andesitic 4,000 ft and 8,000 ft. With the exception of the basalts also underlie much of western Taranaki southern part the main rocks throughout are around the dormant cone of Mt. Egmont (8,260 ft), Mesozoic arkosic greywackes and argillites, with and are present in central North Island around the smaller areas of Upper Paleozoic greywacke and volcanoes Ruapehu (9,175 ft) and Ngauruhoe associated schist particularly in the Marlborough (7,515 ft), which are still active, and around Sounds district. In the south, however, where the Tongariro volcano (6,517 ft). In South Island ranges swing south-eastward into the mosaic of basic and intermediate rocks underlie the steep faulted blocks in Otago, the underlying rock is and hilly land of Banks and Otago Peninsulas schist, although in south Otago the schist moun- and much of the easy rolling land near Timaru. tains are flanked by Upper Paleozoic greywacke, Acidic rocks are confined mainly to the central which in Southland gives place to less indurated rhyolitic plateau in the North Island, where they Jurassic argillites and greywacke. extend north-east to the Bay of Plenty and underlie patches In the North Island the main axial ranges are some 7,000 square miles. Small of dacites narrower than in the South Island and are every- and rhyolites occur elsewhere, notably in the where below 6,000 ft. The rocks are Mesozoic Coromandel Peninsula and on the eastern side of arkosic greywackes and argillites, which near East North Auckland Peninsula. Cape pass into less indurated Cretaceous and From the point of view of soil formation, the Jurassic rocks. Discontinuous ranges of hills, most important drift deposits in New Zealand rarely attaining 2,000 ft in height, and consisting are the glacial and periglacial materials of the Ice of greywackes and argillites, occur in the western Age (particularly the soliflual deposits and the part of the South Auckland district and on the loess), the volcanic ash of central North Island, eastern side of North Auckland Peninsula where the coastal sand drifts, and the alluvium of the they follow a north-western trend. The coastal flood plains of rivers. Soliflual deposits are wide- hills of Wairarapa and Hawke’s Bay are, on their spread in the South Island and on many of the coastal side, composed of greywackes and less hillsides in the southern half of the North Island. indurated argillites and other rocks of Cretaceous Loess is also widespread in the South Island age. particularly in the lowlands, where it is deepest The Tertiary and early Pleistocene rocks lie on and most conspicuous. In Canterbury North the - the flanks of the axial ranges and in many places Otago lowland, and also on the Mackenzie extend to the coast. They are less firmly com- Plains and in the Marlborough lowland, thick pacted and for most part less and loess deposits derived from greywackes and the .folded the sheared than the underlying rocks and consist of argillites cover the downs, and younger loess in grey or brown sandstones, pale grey mudstones most places forms a superficial coating on the late and siltstones, limestones, and conglomerates. In Pleistocene gravel fans of the plains. In Southland the North Island, where they are widespread, they and in Central and south Otago, much of the underlie hilly and rolling land in North and South loess is derived from schist and is richer in chlorite, Auckland, steep land in eastern Taranaki, and epidote, and sericite. In the North Island, loess steep and hilly land in the East Coast districts. In deposits containing volcanic ash are found in the South Island occupy a relatively small Manawatu Wellington and Wairarapa Hawke’s the they - - area. Bay lowlands; northwards to Auckland other Basic and intermediate volcanic rocks with wind-borne deposits consist of volcanic ash. their associated intrusives, Mesozoic to Recent Volcanic ash as recognisable deposits has been in age, occur in numerous areas from North spread far and wide over the North Island, but, Auckland to Taranaki, and in a few places as soil-forming ash beds, it is most widespread mostly east of the main divide in other parts of between latitudes 370S and 400S in the region the country. In the North Island, the older rocks, south of Auckland and north of Wanganui and mainly dolerites and andesites of Mesozoic to Napier. According to origin these beds are of Tertiary age, form steep hills in the north-western two main kinds, namely paroxysmal and inter- part paroxysmal of the North Auckland Peninsula, in the mittent. The ash bed of origin is the

8 II.4GR.4KI

GULF

.o

Coromandel AUCK LAN Perunsula Pacific Ocean ManaAau arbour .,

Tharn

WM .

0aikato River ihi

Tasman Sea East Cape

Raglan Hurhou K " Motu River o T Whakatane

Kuwhia Harbour

L Ro a

Rotorua Ta ra \ TI

1

1 Mohn River Taupo . L IVai arenwana 1 Gisborne

Taupo \

/ I New Plymouth /,

Wairoa +1 .;

Tukituki River Cape Kidnappers

it River uneanui

Scale Miles of

10 0 20 40 60 I I 3 Inch thickness boundar .1 Prepared from data by RSGibbs 1962 ***** Local patches soil Rounders unknown ofolder asher

LEGEND

Ngauruhoe ashes N Kaharoa ashes K Stratford ash 5 A . Rotomahana ash R Taupo ashes Tz Ts TI Tongariro ashes TO Tarawera ash T Waimihia ash Y Egmont ashes E

Rurrell ashes B :::: Whangamala ash WM Tirau Waihi ashes - .T-W Rangirolo ash RO Mairoa Hamilton ashes M-H - -

FIG. 1-2-1- Surface pattern of soil-forming volcanic ash, North Island, New Zealand. Photo, N.Z. Forest Service, by J. H. Johns, A.R.P.S

PLATE 2. Podocarp forest on gley podzol near Wanganui Inlet, Westland. Photo, N.Z. Forest Service, by J. H. Johns, A.R.P.S.

PLATE 1. Beech forest on yellow-brown earth near Murchison, Nelson. PLKrE 3. Kauri grove on brown granular clay, Waipoua Forest, North Auckland. Photo, M. Redican

PLATE 4. Broadleaved forest on central yellow-brown earth near Judgeford, Wellington. MEAN ANNUAL RAINFALL

AUCKLA AUCKLA

NEW PLYMOUTH NEW PLYMOUTH

NAPIER NAPIER 1

ON N ON WEL

HOKfTIK ONRRA

CHRISTCHURCH TEMPERATURE HRISTCHURCH

OF

MEAN TEMPERATURE

Sea Level) (Reduced to

AND

PREDOMINANT WIND DIRECTION

DUNEDIN 50

INVERCAR 1.

PREDOMINANT WIND DIRECTION

9 3 p.m.) (Based on observations at a.m., noon, and

Stight * Marked Pr Pre ce ce

Winds of all speeds (exctuding calms)

Strong (over 13 winds only mph.)

20-35 from directions *Slight Predominance per cent of winds all from dirations t Marked Predominance 36-55 yr cent of winds all

FIG. I’3-1- New Zealand climatic data for rainfall, temperature, and wind (McLintock, 1959). 1-2

younger beds of central result of an eruption burying the former soil turn underlie the ash generally North Island. The main soil formers of central beneath a thick bed of ash, which is this Taupo Pumice ash beds sorted into layers with the finer material above region are the rhyolitic paroxysmal origin erupted about 131 A.D. (SCO and the coarser below, or into a succession of of Pullar, 1964). They are for coarse and fine layers without a break in time Healy, Vucetich, and part coarser below. sufficient for significant soil formation. During the most sandy above and One in places significant amounts the ensuing period of soil formation, the beds member contains member was hot become weathered near the surface while the of charcoal--evidence that this forest. They are under- lower parts are still comparatively fresh. Ash enough to char an existing part by beds one of which, beds of intermittent origin accumulate by the lain in similar on the Waimihia, fossil soil is developed dating back slow additions of dust from small eruptions, or a 1000 These older beds give rise at a distance from volcanoes where paroxysmal to about n.c. to give at south-eastern margin of the Taupo eruptions rise to successive thin layers of ash. the soil the Bay. They are mostly fine in texture and are not neces- ash in Hawke’s Tauranga, Whakatane, and Te Whaiti sarily of uniform composition, since the accumulat- Between in Bay Plenty lowland and on hilly land ing dust is transported through the air for long the of to Kaharoa ash bed, which was erupted distances and from time to time may receive addi- the south, the Over greater 1150 Taupo and Whaka- tions from different volcanoes. the about A.D., Overlies the and is parent material of the soil part of the area of accumulation each coating of tane ashes the area (Healy, Vucetich, and ash is generally thin and has little effect on the over much of the is Pullar, 1964). It is rhyolitic in composition, but existing vegetation; thus soil formation not pumice of Taupo interrupted (although modified by the addition the is less vesicular than that the Overlying Kaharoa between Rotorua of unweathered material at the surface), and the ash. the Whakatane Rotomahana mud and ash bed may be uniformly weathered throughout. and are the basaltic Tarawera lapilli, which were erupted I The distribution of the main ash beds recognised the in 1886. Around Ngauruhoe and Ruapehu, as important soil formers is shown in Fig. 1-2-1. the Ngauruhoe ash, which is still accumulat- The oldest and most weathered of these, the andesitic higher parts of Hamilton ash beds, are mainly andesitic. They ing, gives rise to the soil on the plateau. give rise to soils of heavy texture on the rolling the central Sand drifts of Pleistocene and Recent ages hills of the Waikato lowland between Pukekohe bordering many parts of and Hamilton. They are recognised in buried occupy narrow areas S. They are most extensive on west soils near Gisborne and Kimbolton (Mr H. the coast. the lowland, are Gibbs, pers. comm.). Overlying the Hamilton coast of the Manawatu where they beds, derived partly from volcanic ash brought down by ash on the east are rhyolitic ash the upper- in ferromagnesians, mag- most of which are called the Tirau ash beds and the rivers and are rich minerals. Similar sand drifts cover the rolling land from Morrinsville to Tirau. netite, and related border of North Auckland. On the East of the Hauraki depression the rhyolitic Whaka- the west coast of North Auckland sand drifts are tane and Waihi ash beds are extensive and are east coast the beds largely quartzose. tentatively correlated with similar ash of the gravels, mainly East Cape district. Overlying the Hamilton ash Alluvial sands, silts, clays, and both late Pleistocene origin, are on the west, the Mairoa ash bed contains of Recent and the parent flood plains and rhyolitic and andesitic layers (N.Z. Soil Bureau, rocks of the soils on parts compo- 1954) and covers the coastal hills from the Waikato terraces in many of the country, their into depending of adjacent country River to Ohura. Southward it merges the sition upon that the derived. The extensive Egmont andesitic ash beds, which extend over the from which they are most persist in northern part of rolling lands of Taranaki and still as deposits of these sediments the land New Zealand in Hamilton basin and the remnants on much of the associated steeper are the for most and in places as far south as Wellington. Hauraki lowland, where they consist the part gravels by various In western Taranaki the Egmont ash beds are of rhyolitic covered thick- and sands derived overlain by the andesitic Stratford ash beds, which nesses of water-sorted silts from ash with some admixture are in turn overlain by the Newall and Waiweranui mainly rhyolitic in places; at northern end ash beds dated about 1604 A.D., the Burrell and of andesitic material the partly Tahurangi of Hauraki lowland sediments are Puniho ash beds of 1655 A.D., and the the the and are clayey in Similar deposits Ash dated about 1755 A.D. (Druce, 1966). In eastern estuarine texture. flats of Waikato Taranaki the Egmont ash is overlain by the cover the near the mouth the deposits andesitic Tongariro ash beds, which form the River. Other somewhat similar to these physical properties but derived from material soil of Ohakune Raetibi district and in in the -

9 1-3 of mixed sedimentary and basic volcanic origin finer alluvium of the flood plains are derived cover the Ruawai and other flats bordering the from schist except in places where the plains abut Kaipara Harbour, and the flats of Awanui in the Tertiary hills or the greywacke ranges to the far north. Further south the Gisborne, Wairoa, north-east. The alluvium of both the Taieri and and Heretaunga Plains on the east of the main Lower Clutha Plains is also derived mainly from divide, and the Manawatu Plains on the west, schist. In the Southland lowland the alluvium of consist of alluvium derived from greywacke and the flood plains of the Mataura and Oreti rivers associated younger rocks (mostly mudstones) and is derived mainly from greywacke and schist from volcanic ash, which in places forms separate except on the Five Rivers plain, where it is ad- alluvial beds. In the inland depression containing mixed with basic and ultrabasic material. The the Takapau, Dannevirke, Pahiatua, and Waira- gravels of the terraces north of the Hokonui Hills rapa Plains the terraces consist of greywacke are derived mainly from greywacke. Further west gravels covered by sediments derived in part, or the alluvium of the Aparima and Waiau rivers is in some of the northern areas almost wholly, from more mixed in composition; and the gravels and volcanic ash; the flood plains are covered with overlying silts of the terraces of the Te Anau alluvium of mixed origin and mostly of medium basin and, to a less extent, of the Winton flats texture, although in places, notably around Lake contain much igneous material. The lowland of Wairarapa, it is heavier. Similar terraces and flood the West Coast is occupied mainly by terraces plains occur in the Manawatu lowland. underlain by gravels derived from granitic rocks, The most extensive plains in the South Island siliceous greywacke, and schist. The terraces are plains are those of Canterbury and north Otago. They separated by short narrow flood of allu- consist for the most part of fans of greywacke vium of medium texture and similar composition. gravels of late Pleistocene and Recent age, with Peat deposits are distributed throughout New a thin covering of loess blown from the river beds; Zealand although occupying a relatively small total the rivers are bordered by narrow flood plains of area. They are formed from a wide range of silts, sands, and gravels, derived mainly from plant residues, the different kinds of sedentary greywacke materials; the flood plains of the rivers peats (moss, herb, and woody) being well repre- coalesce near the coast in mid Canterbury to sented. Sedimentary peats, on the other hand, are form a low-lying coastal fringe. On a smaller relatively uncommon. In general, the peats of scale similar conditions prevail on the Southland the north are more decomposed than those of the Plains and on the Wairau Plains and elsewhere on south. The most extensive peats are the basin the eastern coast. Near Nelson, the alluvium is peats, best represented in the Waikato and Hauraki more heterogeneous in composition. lowlands and in the Southland lowland near The intermontane basin of the Mackenzie Plains Invercargill. Other peat deposits, transitional to and the similar but smaller inland basins to the blanket peats, occur in patches on the uplands, north-east are floored mainly with greywacke where they are associated with hollows and flats gravels, generally with a thin coating of loess; from which they have spread on to adjacent slopes. part the flood plains are of relatively minor extent. They are most common in the southern of In similar basins among the block mountains of the South Island but are found elsewhere in the Central Otago the gravels of the terraces and the wetter subalpine parts of the axial ranges.

1*3* CLIMATE

New Zealand, lying as it does in mid ocean climate makes its nearest approach to the con- and within temperate latitudes, has an overall tinental type. (Kidson, 1932.) temperate and insular climate, for the most part The length of New Zealand (over 14o of latitude) without extreme seasonal or daily fluctuations of and the sharp relief of the islands (considerable temperature.. It lies in the zone of prevailing areas of South Island lie above 5,000 ft) are westerly winds, and, although it is too narrow to sufficient to produce a significant range of tem- have a very marked effect on the general tempera- perature from north to south and with altitude. ture of the air, its high relief has a profound effect Mean temperatures at sea level are approximately upon airflow and upon the vertical distribution of 590F in the north, 54or about Cook Strait, and 490, temperature and moisture in the lower air layers. in the south, and these fall about 2-708 for each This effect is especially marked in the South Island, 1,000 ft of elevation (see Fig. 1-3* I). where on the eastern side of the main range the The prevailing westerly winds are forced up

10 1-4

2*7 has been applied most and aside by the mountain ranges causing con- Chapter the method to in New Zealand and some in siderable diversity of rainfalls. In general the climate stations the Pacific islands, and results are discussed in more directly a locality is exposed to the westerly the greater of in neighbourhood. wind and the higher it is above sea level the relation to classes soils their general for Water and precipitation curves for four is the rainfall. The tendency wetness need of Tour maiti soil groups on the west and dryness on the east of the moun- stations representative South are shown in Fig. 4 1 3 (Chapter 4). tains reaches extremes in the southern - - districts both islands hot dry Island (Fig. 1-3-1), more than 200 in. of rain In eastern of from north-west, frequent in a year falling on the western side of the Southern FBhn winds the extend periods Alps and less than 20 in, in the Central Otago spring and summer, tend to the moisture is deficient for plant growth. basins on the eastern side. when soil dust from braided river beds Soil development is strongly influenced by They also carry the lands rejuvenating soils. seasonal variation in the moisture regime. Day onto neighbouring thus the Comparatively few are experi- length fixes the time available for photosynthesis, thunderstorms in New Zealand year, and occur and since it increases southward in summer it enced each they in and west. Nitrogen compounds reduces the significance of the temperature contrast mostly the north in produced in are probably of less between the north and south of New Zealand thunderstorms from organic residues determining the annual moisture requirements significance than are those by from sea and deposited of plants. Thornthwaite (1948) developed a method caught up wihds the (Wilson, 1959). of estimating average monthly potential evapo- in snow and rain Sunshine is plentiful over whole of New transpiration, balancing it against rainfall to the Zealand exception of certain cloudy obtain the water balance in the soil, and finally with the it increases contrast be- arriving at a moisture index and a thermal- mountain regions; the day which is marked efficiency index (which incorporates day length tween and night temperatures, frosts are common and is expressed in the same units as precipitation). in inland regions where night freezing and is a The method integrates the effects of climate, soil, in winter. Frequent thawing given potent factor in of soils in high country and vegetation, and allows a measure to be erosion the In plant cover has been damaged or destroyed. to seasonal variation in the moisture regime. where

1*4- VEGETATION (Plates 1 to 4)

possibly induce growth of bracken The vegetation of New Zealand developed moa and to the during a long period of isolation from other fern. later large Between 1200 and 1400 A.D., however, lands and in the absence of man and of all important food crop, grazing and browsing animals except birds. Climat- migrations arrived with an free kumara, grew well in warmer parts ic, topographical, and soil factors thus had the which the Zealand. Consequently, with passing play, and a closed vegetative cover resulted except of New the paved for a more settled in such sites as coastal sand dunes and in upper of the moa, the way was greater food crops, lead- subalpine and alpine areas where an open type of society with reliance on places, particularly in North vegetation evolved. ing in favourable dating Island, denser populations and to a more According to both tradition and carbon to forest. Inevitably New Zealand has been inhabited by the Maori widespread destruction of the practised agriculture, but in people for less than 1,200 years. The earliest the Maoris shifting places developed a system of inhabitants, the moa hunters, were a hunting and they ultimately permanent based in part on gravel- fishing people. When they arrived they found a agriculture fertilised and charred material rich and numerous bird population that included mulch with ash fires. This was upset by many genera now extinct, the most important from slow system the introduction iron and of potato, which being the large flightless bird the moa. With such of tools the careful soil pre- a plentiful food supply, they had little need of grew well without the traditional agriculture, and, if they practised it at all, it was paration. Before European settlement these two have initiated a period of forest probably a very minor pursuit. For a source of factors appear to destruction and soil exhaustion reminiscent on a starch they resorted apparently to the rhizome of initiated with coming of the native bracken fern. Their main influence on small scale of that the the Age Europe. (Taylor, 1958 and 1962.) the soil was through their modification of the Iron to districts as in parts of Hawke’s vegetation, which they burned when hunting the In subhumid

11 1-4

Bay, Wairarapa, and the eastern coast of South bog-forest soils, as in Westland where condi- Island, fires caused the forest over wide areas to tions were inimical to the hardwoods. More but podocarps give way to grass, scrub, and fern. Even in humid normally there were a few large per dense hardwood- districts growth of fern and scrub were induced and acre, towering over a forest maintained by burning in parts understorey repeated as of . . the . North Auckland, Waikato, Bay of Plenty, (2) the Kauri forests. In the forests of the far north, pumice-covered part North central of Island, the to the north of the ’kauri line’ kauri . . . East Coast of North Island, and around South (Agathis australis) occurred frequently, or was locally dominant. Taranaki Bight--especially where the rainfall tend- Otherwise the forests were podocarp ed be unreliable akin in type to mixed hard- to or where the soils were suffi_ the - wood forests, though with many additional ciently leached to impede regeneration of forest. hardwood species. Kaun forests were former- The critical rainfall determining whether forest or ly much more extensive in the Auckland grassland persisted was approximately 30 in, to Province, as was shown in the widespread 35 in. per annum. Before European settlement occurrence of kauri gum in the soil. practically the whole of North Island and the northern, western, and southern parts of South (3) Beech and beech-podocarp forests. Forests in which one or more of southern beech Island were forest or shrubland, while on the the (Nothofagus) species were dominant. Except eastern side of South Island grasslands were ex- at high altitudes or in low-rainfall inland and tensively developed. eastern regions, there was usually some ad- mixture with species of the podocarp mixed - hardwood forests. There was a full range of PRE-EUROPEAN VEGETATIVE COVER intermediate forest types-beech forest to podocarp mixed hardwood forest-particu- In addition to modifications by the Maori - larly in the north-west and south-west of whabitants,. the composition and pattern of dis- the South Island and at mid-altitudes on tribution of pre-European vegetation reflect the the mountains of the North Island. Minor both long isolation from other land masses the areas of beech forest occurred within the podocarp and the magnitude of the changes that the country - mixed hardwood forests . . . has experienced throughout the past 20,000 years- ice from the retreat of the the mountains of the GRASSLANDS south, with a corresponding flooding of low- the (4) Lowland short tussock grasslands. Tussock lands post-glacial in consequent on the rise sea (bunch grass) grasslands, generally with level; the advance to, and the retreat from, the species of Poa and Festuca dominant. These period principally of maximum warmth; and the devastation occurred at altitudes below 3,000 ft of much of the central North Island by volcanic in eastern South Island regions, though there action. was one lesser area of the type in Hawke’s Bay. Normally low The main classes of native vegetation are out- there was much scrub with enclaves of pure scrub land even of lined by Holloway (1959) and shown on his maps; or forest (beech or podocarp). There were also descriptions follow are quoted from his the that pockets Poa-Festuca grassland paper, of throughout the scrub land.

(5) Subalpine grasslands. Snowgrass (Danthonia FOREST physiognomic favescens[*]) was the or char- (1) Podocarp mixed hardwood forests. Forests grasslands - acteristic species. These were most characterised by the frequent occurrence, or widely developed on the mountains of the local dominance, of softwood timber trees South Island at altitudes exceeding 3,000 ft, belonging to the family Podocarpaceae, the though there were pockets at lower altitudes. principal genera being Podocarpus and Dacry- There was much bare rock with extensive diurn (rimu, miro, matai, kahikatea, and development of herbfield, moorland, and There were also a great number of totara). subalpine scrub, while on flat-topped associate hardwood species, many belonging the block mountains of Otago peaty moorlands or subtropical fanulies or genera to tropical were particularly extensive. These many of and hardwoods were common- trees, these (subalpine grassland, herbfield, moor- ly floristically dominant, particularly in high- types land, scrub land, and subalpine barrens) altitude forest. From south to north these cannot be separated on any small-scale map. forests increased in general luxuriance and podo- in floristic wealth. Heavy stands of the (6) Lowland tall tussock grasslands. Danthonia carp species were normally found only where rigida[f] was the physiognomic species. The rapid changes were in progress, as in the forests about Lake Taupo, or on swamp or *Now Chionochloa spp. TNow Chionochloa rubra.

12 1-4

principal area for this type of grassland was dominant in the swamps; sphagnum moss in on the Southland plains and on the down- with stunted manuka the dominant the lands of South Otago, smaller areas being bogs. Islands of swamp and bog forest oc- found on high level plateaus in the central curred throughout. forth Island. There was much interspersed DUNE LANDS bog and swamp, manuka, scrub land, and forest (9) Moving sands bare or almost bare of vege- . . tation. Only the most extensive areas are shown. SCRUB AND FERN LANDs

(7) No attempt has been made to distinguish ALPINE BARRENS principally between scrub land and fern land, or between (10) Lands above 5,000 ft (South the many separate classes of scrub land. Island) or 6,000 ft (North Island). Bare rock, Bracken fern and manuka (Leptospermum) snow, and ice, with little or no vegetation

. . . were the usual dominants though many other scrub species were also well represented. To a very large extent these scrub and fern PRESENT VEGETATIVE COVER lands were in areas recently devastated by by deliberate firing. In volcanic action or With European settlement extensive areas of all presence other regions, however, the of forest in both Islands have , classes of and scrub natural scrub lands was indicative of soil been felled and burnt to make way for exotic poverty or of soil-moisture insufficiency. The pastures, which are maintained by boundaries between forest and scrub land, topdressing and controlled grazing. Although problems of as set out in the maps, must be taken as instability persist hilly semi-diagrammatic only. In actual fact they reversion and still on the were highly irregular, and there were many and steep lands, they are being steadily overcome programmes islands of forest within the scrub lands and by soil-conservation including such many pockets of scrub land with the forest. practices as aerial topdressing, planned sub- Moreover, boundaries far from these were division, and strategic tree planting. Between 1924 being With static, subject to rapid change. and 1936 some 500,000 acres of exotic forests, every respite from burning, the forest re- mainly pines, were planted, about four-fifths on advanced, and with every fire, more forest pumice of North Island. By degraded land. the soils the central was to scrub 1961, were 945,000 acres of exotic forests. (Subalpine scrub lands, extensive on the there The native forests remain have been modified high mountains of the South Island, are not that particularly separately shown but are included with by introduced animals, deer and opos- Subalpine grassland, Section 5.) sums, leading to increased instability in various key areas such as the headwaters of main rivers. grassland has been SWAMP LANDs The tussock of the lowlands into land (8) Only the most extensive bogs and swamps converted arable with cultivated crops pastures grasses. In places are shown on the maps. They were to be or of exotic some found throughout the whole country, par- afforestation with exotic pines has been undertaken. plains. New ticularly on the Westland Zea- In the higher country nearly all the remaining land (Phormium frequent flax tenax) was a grassland has been depleted by continuous grazing by sheep and rabbits and by repeated burning. At present, however, steady improvement is being Pre-European Present (1961) TABLE l-4-1- and effected by intensified rabbit and fire control, by Vegetation in New Zealand more careful stocking, and by surface sowing and aerial The open subalpine and alpine Pre-European Present topdressing. (acres) (acres) vegetation has also been affected by deer, chamois, and other animals, and by the summer depasturing 41,000,000 23, O and of sheep, increasing the natural instability of these c adn o Tussock grassland 17,000,000 13,035,000 areas. On the coastal sand country, much of the Open subalpine vegetation 900,000 900,000 more stabilised land including especially the inner Alpme vegetation, bare rock, dunes has been successfully pasture. and ice 6,000,000 6,000,000 sown to Coastal dune vegetation 300,000 150,000 Protective planting with marram grass, lupins, - 18,345,000 and exotic pines has progressively reduced the Tva orchards, drifts. and gardenseTllan 1,415,000 threat of advancing sand - Lakes and rivers 800,000 800,000 The changes in vegetative cover from pre- Boroughs, roads, and railways 900,000 - European to present times are roughly of the 66,000,000 66,000,000 order indicated in Table 1-4*1.

13 1-5

1-5- AGE OF THE SOILS

Time for soil formation, during which environ- The age of soils is also affected by erosion and mental conditions have been relatively stable, associated accumulation. Consequently it is related varies from site to site. Throughout the temperate to the position of the soil in the landscape. Where zone, soil formation was interrupted by the glacial the surface is steadily being lowered, as on plateaus periglacial processes parts and of the Ice Age (such as and the upper of slopes, the soil is invading abrasion by ice, solifluction, and deposition of the parent material below so thal; lower horizons moraines, outwash plains, and loess.) These pro- have been part of the soil for a shorter time than cesses removed the former soil mantle, or disturbed the upper horizons. Where the surface is gradually and mixed it, or buried it under the new accumula- being raised by accumulation, as on flood plains tions. Consequently, even on sites that are now and the lower parts of slopes, the lower horizons stable, few soils in the region are older than 20,000 of the soil tend to be the oldest. years, and many are younger than 10,000 years. Where erosion and sedimentation are rapid the This contrasts sharply with the tropic and sub- age of the whole soil is affected. Thus the soils on tropic zones, where soil formation for the most slopes and on flood plains are generally younger part continued uninterrupted by this zone-wide and less developed than those on stable surfaces. soil-destroying catastrophe. In consequence, time In the relatively young and deeply dissected land as a soil-forming factor virtually divides New mass of New Zealand, where tectonic uplift is Zealand into two parts, the subtropic north where still continuing, soils of various ages such as those the soil skeleton by and large has had sufficient on old residual surfaces, terraces of different levels, time to become well weathered so that clay is the flood plains, and steep slopes, are all common predominant texture, and the temperate remainder features of the complex pattern of the landscape. where the soils are younger and the soil skeleton On slopes protected naturally by forest, erosion still contains much weatherable mineral material takes place mostly by mass movements such as so that the textures are predominantly loams of slips, which expose new parent material for soil various kinds. formation. With the removal of the forest this Soil-destroying catastrophes of local origin also process becomes more rapid, and at times of affect the age of soils. Thus the series of volcanic severe storms or during periods of strong earth eruptions in North Auckland, ranging in age from tremors it becomes locally cataclysmic. produced 300 to more than 40,000 years, gives rise to a series Other young land surfaces have been of soils of different ages, and this is reflected in by stream capture, such as that of the Waikato the stages of development of the soils. Similarly River, whose change of course resulted in the the soils of the volcanic ash beds in central North building of the mid Waikato Plain; and smaller Island illustrate the effect of the age of volcanic areas of new soils have developed on land raised eruptions upon the age of soils, an effect that is during earth movements, for example, the earth- most marked by differences in the content and kind quakes of Wellington in 1855 and Napier in of clay to which the ash material has weathered. 1932.

1*6* REFERENCES

DRUCE, A. P. 1966: Tree-ring Dating of Recent Volcanic N.Z. METEOROLOGICAL SERVICE, 1959: Climate. Map 8 in Ash and Lapilli, Mount Egmont. N.Z. J. Bot. 4: ’A Descriptive Atlas of New Zealand’, edited by 3-41. A. H. McLintock. Govt. Printer, Wellington. FLEMENG, C. A. 1959: Introduction. Pp. 5-12 in Lex. stratigr. N.Z. Solo BUREAU 1954: General Survey of the Soils of int. 6, Oc6anie, (4). North Island, New Zealand. N.Z. Soil Bur. Bull. 5. GRINDLEY, G. W.; HARRINGTON, H. J.; WOOD, B. L. 1959: 286 pp. The Geological Map of New Zealand, 1:2,000,000. SHAW, G. C. 1959: New Zealand Geology. Pp. 13-18 in N.Z. geol. Sury. Bull. n.s. 66. Ill pp. ’A Descriptive Atlas of New Zealand’, edited by A. HEALY, J.; VUCETICH, C. G.; PULLAR, W. A. 1964: Strati- H. McLintock. Govt. Printer, Wellington. graphy and Chronology of Late Quaternary Volcanic TAYIDR, N. H. 1958: Soil Science and New Zealand Pre- Ash in Taupo, Rotorua and Gisborne Districts. history. N.Z. Sci. Rev. 16: 71-9. N.Z. geol. Sury. Bull. n.s. 73. 88 pp. - 1962: Soils and Mankind: The Problem of the Food- HOLLOWAY, J. T. 1959: Pre-European Vegetation of New hungry World. Cawthron Lect. 36. 27 pp. Zealand. Pp. 23-4 in ’A Descriptive Atlas of New THORNTHWATTE, C. W. 1948: An Approach toward a Zealand’, edited by A. H. McLintock. Govt. Printer, Rational Classification of Climate. Geogr. Rev. 38: Wellington. 55-94. KIDSON, E. 1932: Climatology of New Zealand. In WILSON, A. T. 1959: Surface of the Ocean as a Source of ’Handbuch Klimatologie’, Borntraeger, Berlin. Air-borne Nitrogenous Material and Other Plant Ill pp. Nutrients. Nature, Lond., 184: 99-100.

14 CHAPTER 2. CLASSIFICATION OF NEW ZEALAND SOILS

by N. H. TAYLOR and I. J. POHLW

2-1- INTRODUCTION

Soil work in New Zealand, and particularly material. The interpretative or genetic approach the mapping and classification of soils, developed based on the recognition of broad soil groups is in an atmosphere of comparative isolation from the subject of this analysis, the purpose of which the rest of the world. It contains many imperfec- is not to evolve a new classification but to examine tions, as New Zealand pedologists are only too logically the one that has already been evolved to well aware, but it has served New Zealand well, meet New Zealand conditions and is at present has withstood critical examination by the chemist, in use. the physicist, and the biologist, and above all has Because of the early period of isolation, many assisted the progress of land development through New Zealand soil terms have tended to be used in providing a difficult state by a new basis for the a local sense and are not acceptable to workers study of many agricultural and forestry problems. overseas. Other terms, introduced tentatively as With the coming of closer liaison among pedolo- common names, are too long for technical use gists throughout the world, New Zealand methods particularly for the expression of intergrades. will undoubtedly change. Before these changes Many of the common names are necessarily proceed too far, the present system and its philoso- somewhat inexact and have a strong land-use phy need to be recorded so that such good features bias. In the interests of precision, therefore, certain as exist may be preserved. words have had to be coined in presenting this Two main approaches have been adopted. First, classification, but they have been kept to a mini- in order to meet immediate agronomic needs, soil mum. They are not intended to replace the common purely purposes, types were recognised and mapped; they were names for other than technical grouped into series, and various attempts were since pedology, if it is to live and be part of the made to group them into families following early everyday thinking of land users in general, should practices in the United States (Taylor and Pohlen, have a popular terminology suited to local needs. 1962). Secondly, to facilitate soil and related The new terms should be regarded merely. as investigations, broad soil groups were recognised technical translations of the popular or.common and subdivided in an interpretative way according names in order to permit the more precise nomen- to soil-forming processes. Various arrarigements of clature required for scientific use. the classification have also been used for particular The classification is based mainly on studies in investigations, notably the soil suites which com- the New Zealand sector, which extends from the prise soils from like parent materials arranged in antarctic to the tropic zones, the climate through- order of profile development, thus allowing char- out being for the most part oceanic and lacking acteristics acquired during soil formation to be the seasonal extremes associated with continental separated from those inherited from the parent conditions.

2-2* SOL FORMATION

The soil is a dynamic system activated by the skin of the subaerial part of the earth’s crust.’ sun’s energy. As Nikiforoff stated (1959, p. 186), At any one site the system is not a closed one. ’Without agronomic bias, the soil or its geo- It is receiving material from outside sources and chemical equivalent might be defined as an excited is losing material to the broader geological cycles of rock weathering and rock building; and its SECTIONs 2, 6, and 8 of Chapter 2 are reproduced for this nature is determined by the relative effectiveness bulletin with only minor alteration from N.Z. Soil Bur. Bull. of each of the five prime soil-forming factors- 25, Soil Survey Method, by N. H. Taylor and I. J. Pohlen, 1962. climate, living organisms, parent material, topo-

15 2-2

purposes graphy*, and time. It changes in response to any For of analysis the soil system may be change in any of the soil-forming factors, the effects divided into three interdependent parts (Taylor, being reflected in greater or less degree in the form 1949, pp. 111-12)-the wasting, organic, and drift of the soil body. Despite efforts to deprecate time regimes. as a soil-forming factor, the soil system does change with time, and in some circumstances it changes On however, it a rapidly. the whole, tends towards WASTING REGIME nearly steady state in which overall changes are slow in human events. This relation to nearly The wasting regime includes the processes of gives bodies steady state rise to soil that are rela- both physical and chemical weathering, together in form long periods- tively stable over with the associated concentration of elements in Between soil and body is a the the soil there various horizons and loss of elements in the drain- distinction. is dy- real and necessary The soil a age waters. namic entity that embraces not only the lifeless The most important aspect of physical weather- constituents but also living organisms within the ing of the soil is comminution, the mechanical it including plants. The body, the roots of soil on breaking of the mineral parts of the soil into finer the other hand, is the lifeless medium, formed of and finer fractions. It is particularly active in inorganic in and organic materials, which the regions where the soil is subject to a wide range living It is body organisms operate. the that of temperature fluctuations, especially where this impression factors, retains the of the soil-forming is accompanied by freezing and thawing, and in as in most soils by development of reflected the arid and other regions where the soil lacks the horizons gradual soil which are the result of insulating protection of vegetative cover. changes with time. The most important aspect of chemical weather- Many bodies persistent soil retain the more ing of the soil is argillisation. If processes condi- developed in periods characters earlier of their tioned by the organic regime be excluded, it con- history when the combination of soil-forming sists of the decay of the mineral skeleton of the factors different. By body was some the old soil soil-the breaking down of complex minerals to is parent regarded as merely the material of the simple more inert ones by a series of reactions(Poly- present By is soil. others the old soil considered nov, 1937, pp. 15-22; Nikiforoff 1959, p. 188) such persist present-day to modified by conditions. If, as oxidation and hydration, which dissipate in- however, is the soil regarded as a system embracing trinsic energy. For a given argillisable mineral its life soil and tending towards a nearly steady rate is dependent on the background temperature is focused it state, attention on the soil as and the supply of air and moisture, and hence functions here Thus and now. a soil that retains proceeds faster in the soils of warm moist regions impress present an obsolete that modifies the than in the soils of cold dry ones. The kinds of be having polycyclic system may regarded as a argillisation leading to the particular kinds of body, but it is polycyclic soil strictly not a soil. residual products and their primary aggregation are dependent on the nature of both soil skeleton *In its pedological sense, topography is generally restricted but, in general, to land form (see Joffe, 1949, pp. 129-31). and weathering environment;

TABLE 2 l Relative Mobility of Elements During Weathering of Rocks (Polynov, 1937, p. 162) -2 - *

Average Average Composition of the Relative Mobility of Composition Mineral Residue of Elements and Compounds of Igneous Rocks River Waters

0 SiO, 59 -09 12 -80 -20 AlsO, 15-35 0-90 0-02 FezO, 7 0 0 -29 -40 -04 Ca 3 60 14-70 3 - -00 Mg 2-11 4-90 1-30 Na 2 97 9 50 2 40 - - - K 2-57 4-40 1-25 Cl’ 0 6 100 -05 -75 -00 SOa" 0 15 11 60 57 -00 - - COa" 36-50

..

*These figures are approximately the average composition of the lithosphere (Clarke, 1924, p. 34).

16 2*2

and soil air. argillisation leads to loss of bases and silica to the and on soil moisture by drainage water (Table 2*2-1) and to concentra- 2. Cycling of mineral elements organisms surface horizons from tion of the sesquioxides and simple compounds that return elements to containing them. lower depths. With the movement of water through the soil, 3. Conditioning of leaching, illimerisation, and processes the of soil weathering are accompanied argillisation by modifying the chemical and from horizon by the translocation of minerals one energy balance. and, especially in humid regions, by to another, 4. Mixing within the soil. losses from soil system by removal of the the 5. Modifying comminution, by physical attack elements in drainage waters. These soluble the from by insulation from ex- by organisms and associated processes include leaching (loss of temperature. solution) and illimerisation* (translocation of tremes processes drift illuvial 6. Modifying of the regime- colloids), both of which lead to eluvial or erosion and accumulation. concentrations that may result in the formation of pans. On decomposition the organic matter added to plant litter, Although comminution is in many respects a the surface in such forms as animal with similar rejuvenating process, the wasting regime as here droppings, and other residues, together inside from of defined is for the most part a collection of one-way materials added the soil the roots of processes, which, on a stable site, use up the in- plants and from the droppings and remains Were dwell or partly in trinsic energy of the soil skeleton. these other organisms that wholly gives incorpora- processes to operate alone, the wasting soil system the soil, rise to melanisation-the in The darken- would inevitably run down and become inert. tion of humus the soil. consequent in are Of such a condition no examples are known be- ing and associated aggregations the topsoil processes morphological effects cause of the concurrent of the organic among the most conspicuous greater part and drift regimes. of the organic regime. The of this process is carried out by soil micro-organisms as described they fulfil their role in the often carbon ORGANIC REGIME and nitrogen cycles. Mineral elements that would otherwise escape impact of life on The organic regime-the the from the soil system may be caught up in the by intrinsic is soil-is the medium which energy organic cycle and circulated from the soil to the keeps it replaced in the soil system and operating. organisms and back to the soil again and again. dependent life, it from processes process is Being on stems the A simple example of this cycling that place in large part in humid of metabolism, which take associated with a forest tree growing a itself. Basically it depends on drained site. outside the soil the temperate region on a well stable processes photosynthesis by plants in of and the Mineral elements set free by weathering, and of soil with organic drainage subsequent enrichment the the process of being leached away to the The by breakdown by into compounds. energy released the water, are intercepted the roots and taken compounds helps maintain balance leaves of these to the the tree. Those that reach the twigs and in with a corresponding increase await the soil system, are returned regularly to the topsoil, others in (Polynov, 1937, pp. This the endothermic reactions the death of the tree for their return. cyclic by impetus given reduc- part losses by 17-22) as evidenced the to return of elements prevents in the tion and a consequent conditioning of all the leaching. It is most noticeable in the topsoil, processes. part wastmg since it is here that the greater of the minerals be as humic The organic regime may regarded a struggle is returned and it is here (in and on the by life fertility of soil In lower soil to maintain the the fraction) that they tend to be held. the effects of wasting por- process is less against the exhausting the horizons, however, the cycling It is but part of all living by cesses. of the struggle effective, and below the root zone leaching the in Al- organisms to survive their environment. downward moving waters continues freely. The outstanding effects of organic regime given return is the though in the example the cyclic be follows: For may analysed as confined to one site, this is not always so. 1. Addition to the soil system of organic matter example, animals grazing on vegetation on one part droppings different with its supplies of carbon, nitrogen, and site for the most return to a mineral elements, its power to retain cations site-a phenomenon known to grassland ecologists its fertility. Extreme examples ’ and anions, and effects on aggregation as the transference of birds of this kind are to be found where sea nest droppings. on land and enrich soil with their *Fridland (1958). See also Gerasimov (1960). the the

17

B The conditioning of argillisation arising from a period dependent on the life span of the tree; the altered energy balance is dependent on the many forest trees die and rot away without over- kind of organic matter and upon aeration. This is turning-a process that depends on the kind of well illustrated by the example of the tree given forest, the degree of shelter, and the depth of above. Where the tree demands high fertility and rooting. In addition to these obvious examples, cycles plant-nutrient elements strongly, the base- there are many other ways in which mixing is charged organic matter is broken down quickly caused by the organic regime; termites on basalt by organisms’ and is rapidly incorporated in the soils near Auckland transport kaolin clays from soil, giving rise to a mulloid organic profile. Al- adjacent mudstone soils, and even the common though this process, by controlling such properties blackbird contributes its share when, to build a as acidity, undoubtedly does condition argillisa- nest, it carries as much as three-quarters of a tion, its results are not conspicuous in the field pound of soil material that ultimately is returned because it does not reverse the overall trend of to another site. weathering in the wasting regime. Where the Physical weathering of the soil (comminution) tree withstands low fertility and cycles plant is also modified by the organic regime. It is reduced nutrients weakly, the organic matter is broken by the insulating effect of vegetation with its down more slowly and tends to accumulate above associated organic-rich topsoil that protects the the mineral soil as a moroid organic profile. soil from extremes of temperature, and it is in- Under these circumstances the conditioning of soil creased by such means as root penetration and argillisation by the organic regime is patently the swaying of trees. evident: active organic radicles draining from the From the above it is clear that the wasting and moroid horizons above attack mineral particles organic regimes are interdependent, each influenc- and by combining with polyvalent cations peptise ing every aspect of the other. The various kinds the clay; thus, by the process known as podzoli- of wasting occasioned by different kinds of rock sation, secondary silica becomes concentrated in and of climate strongly influence the kinds of products, the upper horizons while compounds of the ses- organisms and their and these in turn quioxides are transferred to lower horizons and condition the wasting processes including weather- may even be lost to the drainage water. Similar ing, illimerisation, and leaching. described reversals of the overall trend of weathering are The processes that have been are prominent in gleyed soils. those on stable sites. Despite the rejuvenating It is essential to recognise the difference between effects of the organic regime, wherever there are the grade of argillisation and the effects of condi- overall losses to the drainage water there is a places tioning by the organic regime. In many the steady decrease in the mineral reserves of the soil. two are out of step because argillisation is a rela- Over a long time the soil skeleton becomes de- tively slow process. Thus, in two well developed pleted of its argillisable minerals and of its bases podzols occurring side by side in the mild tem- other than those cycling in the organic regime. perate zone, the mineral skeleton of one may be Soils reduced to this state occupy many areas on parts weathered conformably with that of other stable stable of the earth’s crust, notably in the soils of the zone while the mineral skeleton of the humid tropics. They support shallow-rooted vege- other is very weakly weathered, for example, if it tation that depends for its continuance on the is formed on pumice ejected from volcanoes a eflicacy of its own cyclic return of plant nutrients. few centuries ago. Although the morphology of If for some reason this cycle is broken, with sub- the two profiles appears so similar, the impress of stantial loss of plant nutrients, vegetative cover podzolisation is etched much more deeply on the of a lower order takes over. An assemblage of soil skeleton of one than on the other. soils in this condition may be regarded as a pedo- Mechanical mixing by burrowing organisms logic peneplain. Such areas are almost confined to occurs within most soils. It is illustrated by the the tropics and subtropics, where argillisation is well known activities of earthworms, which are more rapid than elsewhere and time for soil greatest in moist fertile soils and are favoured by wasting is longer because it extends beyond the conditions such as those under mulloid humus last glaciation. They are simulated in many places (with its high base return), where they tend to where leaching is strong in relation to the release prevent the development of well defined horizons. of elements by argillisation, and where conse- The overturning of forest trees, especially in areas quently soil formation is at a stage not generally growth plants subject to cyclonic storms is a powerful factor in favourable for the of higher although mixing soil horizons. It is wrong, however, to a large proportion of argillisable minerals, with assume that all forest trees overturn as they die their potential for rejuvenating the soil, may still giving rise to a general mixing of forest soils within remain.

18 2-2

be as is indicated by features Were the earth’s surface stable it would of the soil may occur, lines. On graded is a covered largely by these depleted areas (pedologic such as stone slopes there it is between shape of peneplains and their simulations), but since marked correspondence the the not stable, erosion of the land and accumulation slope and the balance of soil-forming, soil-removing processes. The of drift affect soils not only in the unstable areas and soil-accumulating steeper upper parts places where but in adjacent areas as well. This mechanical of the slope correspond to the downhill is greatest, more modification of soil sites by erosion and accumula- movement and the gentle lower soil is tion belongs to the drift regime. slopes to those where the accumulating. Examples have been given of soils that are strongly modified by alluvial and air-deposited DRIFT REGIME accumulations. All soils, however, are subject to The drift regime embraces the mechanical some extent to additions of new materials by disturbance of the soil system by inorganic agencies. inorganic agencies. New Zealand soils, even out- It includes the mechanical processes of erosion side the main areas of accumulation, receive small (movements down slope by gravity, and removals quantities of air-borne dust not only from river by wind and water), accumulation (colluvial, allu- beds but also from the arid areas of Australia, vial, and air-deposited), and mixing (by such together with additions of salt blown inland from means as expansion and contraction). the sea. processes process dis- Where these are so strong that they Flushing-a whereby substances by percolating destroy or overwhelm the soil, they belong to the solved from one site are conveyed realm of geology rather than pedology; but where waters into the soils of other sites-is also referred It they simply modify the soil, as they do on a to this regime. commonly occurs on sloping large part of the earth’s land surface, they are to land and is the medium whereby such compounds hy- be regarded as soil-forming processes. This dis- as soluble salts, calcium carbonate, or iron into horizons tinction is illustrated in the volcanic region of droxides are conveyed the of soils North Island, where the paroxysmal eruption on concave sites. physical is from Tarawera and neighbouring vents in 1886 Mixing within the soil by agencies covered a wide area with lapilli and mud. Near caused not only by downhill movement of the by the main vents, where the detritus was thick, it soil but also by frost action, and wetting and part destroyed the vegetation, overwhelmed the soil, drying, which lead to upward movement of due and initiated a new cycle of soil formation; at a of the subsoil. In New Zealand, mixing to considerable distance from the vents, where the frost heave, with consequent sorting, is common detritus was thin, it barely affected the vegetation in alpine and open subalpine areas where the soil (Zotov, and merely modified the existing soil processes is not protected by a vegetative cover 1960; McCraw, by the addition of unweathered material to the 1938, p. 241; Gradwell, 1957, phenomena surface. Other examples of this distinction occur 1959). Large stone polygons and amed places, on mountain sides, on dune lands, and on the are well developed in many but most of last glacial period. flood plains of rivers. them are clearly relics from the is Although the mechanical processes of erosion In the Ross Dependency there evidence of permafrost by freezing produce many striking examples of soil destruc- mixing of the soil above the great is tion, they modify in a less spectacular way a and thawing on sites where sufficient moisture however, do many soils. On the crests of downlands in North available. Most antarctic soils, not pro- Auckland are soils with clay skins still persisting have sufficient moisture available for mixing 1965). in the surface horizons, showing that as the surface cesses to operate (Claridge, has been steadily lowered by erosion the topsoil Soil mixing due to wetting and drying is most dry has moved down into what was formerly the evident in soils with expanding clays. During partly subsoil. Other examples of this phenomenon have seasons deep cracks are formed and are increases been described for the downland soils of Canter- infilled by material from above which bury (Raeside, Cameron, and Miller, 1959, p. 15). the mass of the subsoil; in wet seasons the aug- part is forced Owing to movement downhill, the soils on many mented subsoil swells, and a upwards process, steep slopes show successive stages of modification into overlying horizons. This churning in ranging from clearly expressed horizons where much less marked in New Zealand than some is indicated by peds the overall movement is very slow, through weakly other countries, slickensided expressed horizons where it is slow, to the com- in montmorillonitic soils of subhumid regions plete absence of horizons where it is rapid. Even and domed columns in solonetzic soils of Central on gentle slopes movement with consequent sorting Otago.

19 The processes of the drift regime are, on the a new source of nutrients to the organic cycle. prevent whole, rejuvenating ones. They tend to They also lead to new soil formation on subsoils the formation of soil horizons, to offset generally or parent materials by thinning or removing the the processes of the wasting regime, and to provide old soil.

2-3- PRINCIPLES AND CRITERIA OF GENETIC CLASSIFICATION

Besides the normal way of describing profile being broad in the higher categories of the classi- and site, a soil may be described in an interpreta- fication and progressively more detailed and com- tive way by reference to the processes of the three plete in the lower ones. previous regimes outlined in the section. This meth- The higher categories of the New Zealand od is used in many sciences where objects are classification are subdivided according to the described in terms pertaining to their origin and following criteria: implying processes have produced the that them. Category I-basal form of the soil body It has advantage of conveying information Category (as indi- the *II-main energy status intrinsic properties about the nature and of the cated approximately by the is identifica- object and thus more than a means of latitudinal and altitudinal zones disadvantage depending tion. It has the of upon and by soil moisture) from reasoning the available evidence and there- Category III-(a) argillisation or (b) the fore is perfect not always nor always completely counter processes of accumula- objective. Since striving for perfection the in tion, removal, and mixing nomenclature is a powerful stimulus further to The classes of Category I cut across latitudinal enquiry, the names tend to change with advancing and altitudinal climatic zones, whereas those of knowledge. Category II lie within Those of Category III geomorphology, them. The sciences of ecology and principal are the classes, many of which are com- whose problems of nomenclature are similar to parable with great soil groups of other classifica- those of pedology, illustrate the value of genetic tions. Names of the classes are derived for the names. For example, a physiographer may des- most part from the names of the basal forms, but cribe a cliff-like feature in great morphological a few are derived from processes of accumulation detail, but he does not convey wealth of the Those in Category I in or removal. end -iform, information given by the geomorphologist in his those in Category II in and those in Category genetic ’obsequent fault-line scarp’. This -ous, term III in Concise technical names for classes are method of naming and classifying soils has long -ic. coined at these levels only. been used by Russian pedologists (Joffe, 1949, The lower categories are subdivided according p. 178; Taylor, 1956, p. 13) and by others, notably to processes and properties of genetic significance Aubert and Duchaufour (1956, p. 597), and is that modify the principal classes as follows: kind one has been used in New Zealand. the that and degree of illuviation, gleying, accumulation, Since, however, the soil embraces both the soil etc., leading to or retarding the development of body and living within it, soil as the things the horizons (IV); state of enleaching (V); parent a system can be adequately expressed only when material (VI); texture and other properties, mainly the soil body and its associated temperature and of the topsoil (VII). Names of the classes in these moisture regimes are considered as one. Many lower categories are descriptive and are derived by soil bodies do reflect the present environment modifying the name of the principal class by quite clearly. However, some old soil bodies appropriate adjectives. retain the impresses of former environments’ The classification of the main soils is necessarily which overshadow of present one. those the considered independently of intergrades, the names Others are too young to reflect the present en- of which may be derived at any level by com- vironment in major definable characters such as pounding class names. are generally chosen for classification purposes. Consequently, either weight be adequate needs to CATEGORY I given body do to characters of the soil that reflect Basal Forms existing soil temperature and moisture, or it must is be given to these properties themselves or environ- The first category of the soil classification distinctive basal forms mental factors that indicate them. built upon 11 of the soil in When soils are classified on this principle, cor- body, which were recognised the earlier stages These basal forms relations with the requirements of living organisms of soil surveys. really represent form, (soil fertility) begin to emerge almost as a corollary, broad classes of each of which characterises

20 2-3

certain sequences of soils. Consequently each basal in humid areas. They have prominent O, and form is defined in only the broadest of terms, differ- ash-grey structureless silica-rich A2, horizons, and ences in detail of morphology of individual soils commonly but not always have humus and iron being regarded as modifications of it. Nine of the illuvial horizons. Owing to the transient nature of basal forms, dominantly all mineral, are character- the O horizon, after clearing of the forest the As ised by developed soil horizons; the remaining horizon is the main differentiating characteristic. two, one dominantly organic, and the other Spadiform (red and brown) soils have red or mineral, lack clearly expressed soil horizons. The brown soil bodies, typically without spectacular names of the soil classes are set out below: differentiation of horizons and with innate blocky - and granular structures that persist even when CATEGORY I particles. ordinary aggregates are crumbled to finer Technical Names Common Names They contain more sesquioxide colloids than do fulviform soils, hence the stability of their struc- ( Sitiform Brown-grey tures. They are commonly formed from basic igneous rocks or from sediments derived from 1 rmm wn Characterised Podiform Podzols these rocks. by developed Spadiform Red and brown Latiform (’ironstone’) soils have a sheet-like horizons Latiform ’Ironstone’ form due in Nigriform Rendzina-like to the arrangement of sesquioxides Soloniform Solonetzic distinct layers that are commonly concretionary. Madentiform Gley Their sand fractions are characterised by secondary Characterised by Orgamform Organic Owing high of lack of developed Skeliform Skeletal minerals. to their content sesqui- horizons (including recent) oxides they have the brown to red colours of the spadiform soils and for the most part are ex- Sitiform (brown-grey) soils are formed in semi- ceedingly friable. arid areas. Topsoils are brownish grey with platy Nigriform (rendzina-like) soils have deep dark horizon. structure, and subsoils are brown. There is little non-peaty topsoils and little or no B obvious development in the profile other than a Generally they have well developed structure. thin topsoil and a marked clay illuvial horizon, They are commonly derived from limestones or which in most places is a stronger brown colour other rocks high in bases, poorly than the horizons above. Soluble salts are present Soloniform (solonetzic) soils are repre- in small amounts, and in many profiles there is sented in New Zealand. They occur in semi-arid deposition of a band of calcium carbonate below areas in low-lying or other places flushed with have greyish the clay illuvial horizon. Owing to the small area soluble salts. They friable topsoils with a semi-arid climate these soils are not widely and hard dark columnar structures with diffuse represented in New Zealand. humus in the subsoils. Although their topsoils Palliform (yellow-grey) soils are formed char- may be low in soluble salts, they have alkali acteristically in subhumid areas. They have well subsoils with a high salt content. The lower parts places developed Ax horizons, grey to very dark brownish of their subsoils in many are lighter in grey in colour and with weak or coarse structure, colour and contain calcium carbonate. A fragipan or genetically similar massive horizon Madentiform (gley) soils have predominantly occurs in most places at depths below 10-24 in. gleyed horizons associated with high ground and is commonly yellowish in colour with a water*, while organiform (organic) soils have gammate or reticulate pattern of grey veins. The bodies dominantly composed of organic matter. common name of ’yellow-grey earth’ was derived Skeliform (skeletal) soils show little or no profile from the general yellowish grey appearance of development and include a wide range of weakly the soil exposed in road cuts and similar excava- developed mineral soils. tions. Sequences of form between basal classes of Fulviform (yellow-brown) soils are character- form are intergrades between the form classes in be level. The istically the humid areas. Typically they are and may considered at this well well drained soils without spectacular differentia- defined sequences of form within each of the broad progressive in tion of horizons although many have illuvial basal classes are due to differences particular horizons commonly of clay. They have yellow to soil-forming factors and are considered brown subsoils, which for the most part have at lower levels of the classification. block-like structures. This basal form is exceed- ingly common and, owing to the effect of modifying *Where high ground water is not present, soils that are dominantly gleyed but be identified as gleyed modi- processes, gives rise to many sequences. cannot fications of other forms may be considered as pseudo- Podiform (podzol) soils are also characteristically madentiform.

21 2-3

CATEGORY II which somewhat resemble the latitudinal zones in Main Energy Status (as indicated ap- effective mean temperatures but differ markedly proximately by the latitudinal and alti- from them in length of day and night and in tudinal zones and by soil moisture) seasonal and diurnal fluctuations of temperature. In New Zealand lower boundary Each of the broad basal forms is the expression the of the alpine soils corresponds with general within the soil body of very broad processes that approximately the limit plant have operated and are operating within the soil. upper of a continuous cover, and the lower boundary is generally Since broad basal forms cut across zones that of the subalpine soils somewhat lower and roughly parallel receive different amounts of the sun’s energy than to upper limit of continuous cover of woody (Fig. 2-3-1) and have different temperature the the (see Fig. 2-3-2). In practice, however, regimes (Fig. 2*3-2), they do not of themselves vegetation boundaries indicate adequately the soil as a dynamic system. the of these zones are necessarily determined by dominant With the notable exception of skeliform, however, reference to the soils and not merely by latitude or altitude. they do reflect the kinds of soil processes governed In is indicated in large measure by effective moisture. Conse- common soil names the zone directly by ’subtropic (yellow- quently, with the exception of skeliform, the soil either such names as brown indirectly by indicating as a system may be expressed approximately by earths)’ or the position zone in New Zealand, e.g. indicating both the basal form and the latitudinal relative of the This from or altitudinal zone in which it occurs. northern, central, southern. arose the early attempts to distinguish the warmer North ac Auckland yellow-brown earths and podzols from generally less further -’ cooler and argillised soils - the ------, south. In the Soil Map of New Zealand (N.Z. - , Soil Bureau, 1948) an attempt was made to use weathering (argillisation) as a zonal indicator; in ,’ general it was satisfactory, but in detail it proved ,’ unsuitable where the actual state of weathering ,/ of particular soil bodies is unconformable with , the overall weathering pattern of the zone. In the technical names the latitudinal zone is conveniently indicated by the simple prefixes ,/ per- (tropic), ad- (subtropic), pro- (temperate), 2000 ,’ / de- (subantarctic), and e- (antarctic), which are added to the form name. The altitudinal zones are distinguished by the additional prefix el- (for 8 elevated)*. Thus the prefix ele- denotes the alpine 6 zone and elde- the subalpine; where in the tropic islands the land is high enough to have a subtropic prefix temperature regime the appropriate is elad-, and so on. To simplifjr the names as much as possible, the prefix pro- may be omitted from the names of soils that are well represented in the zone-that is, of all except spadiform a temperate the latiform better a 0 2> < and soils, which are represented in the subtropics and from the names of which Latitude ("S) the prefix ad- may be omitted. In FIG.2-3-1- Yearly mean of average daily values of the this way the basal forms are subdivided to pndhor sole einer s face give the second category of the soil classification in hemisphere (after Vincze, 1960). which the soils are classified according to their basal form and energy status. Since skeliform gives in In the second category of the classification the no indication of the effective moisture classes of Category I are subdivided accordingly, the soil system and since other forms may cover The latitudinal zones chosen correspond roughly too wide a range of soil moisture for some pur- with those commonly known as tropic, subtropic, poses, it is necessary at this level of the classifica- temperate, subantarctic, and antarctic. The alti- tion, or at the level of Category III, to introduce, ones are approximately alpine, sub- tudinal the *If necessary, latitudinal differences in these zones may be belts, alpine, and other recognised altitudmal expressed as phases (cf. tropic and temperate subalpine).

22 2-3 as needed, phasic subcategories based on the soil ARGELISATION moisture classes outlined in section 6 of this As indicated above, argillisation may be assessed chapter. These may be named either directly from in two ways-by reference to the nature of the (e.g. hygrous the moisture class skelous soils) clay produced (the kind) and by reference to the or indirectly by indicating an associated soil proportion of weatherable minerals converted to (e.g. with a characteristic soil-moisture regime clay (the grade). The kinds of argillisation are co-fulvous skelous soils). designated by the dominant residual clays* pro- Names in Category II indicated of classes are duced. They fall into three broad groups-amor- by suffix as in following examples: the -ous the phous, crystalline layer silicates, and crystalline oxides-which, where dominant, can be recognised degree in field CATE- CATEGORY II with some of accuracy the and used GORY - as criteria for purposes of classification. Names of I Technical names Common names classes with characteristic properties dominated by Perfulvous Tropic yellow-brown amorphous clays and crystalline oxide clays are Affulvous* Subtropic or northern distinguished from those with crystalline layer clays by prefixes amo- and oxi- respec- (Pro-) Fulvous Te r or7outhern silicate the Fulviform yellow-brown tively. To simplify the names, the prefix oxi- is El(pro-)fulvous (Elevatedyellow-brown, soils omitted from the latiform soils as, in these, crystal- corresponding to line usually dominant. Contractions temperate, in tropics oxides are and subtropics) are also used for some other common soils. Thus Defulvous Su yellow- fulvous and spadous soils of Category II are ontarctic the fulviform Eldefulvous Subalpine or high coun- divided as shown below. Other classes of try yellow-brown and spadiform soils in Category II are subdivided similarly. For special investigations clay Perskelous Tropic skeletal the level, Skeliform Adskelous Subtropic skeletal chemist may, especially at this conveniently Moist pckekeetlaltal soils introduce phasesi- based on the clay classes listed PrMISkelous S apnerat 8 Such phases, when Eldeskelous Subalpine skeletal in section of this chapter. kind genetically arranged, represent stages in the of argillisation. *In prefixing ’ad’, the common rule of assimilation is applied. Technical names* Common names Dominant clays For the New Zealand sector, the latitudinal and Fulvic Temperate yellow- Layer silicates altitudinal zones, their approximate ranges of (Pro-) brown earths mean annual temperature, and the nature of their Fulvous associated vegetation are shown provisionally in Alvic Temperate yellow- Amorphous brown loams Fig. 2-3-2.

Spadic Subtropic brown Layer silicates granular clays CATEGORY III (Ad-) Spadous Amadic Subtropic red and Amorphous (a) Argillisation or (b) The Counter------brown loams Oxadic Crys lline processes of Accumulation, Removal, and Mixing Ivic, amadic from In category of classification the third the the amMo a c,aan romom ba classes of Category II that contain mineral soils The grade of argillisation as here defined is with developed horizons are subdivided accord- assessed by the proportion of argillisable minerals ing to the state of weathering of the soil body as (originally in the soil skeleton) that has been indicated by the kind and grade of argillisation clay or clay nodules or of The other converted to through to the soil skeleton. classes, organiform particle it other reaggregations of larger size; is and skeliform, are subdivided according pro- to proportion products thus the of these secondary cesses that tend to oppose the formation of horizons argillisable minerals in soil after allow- and progressive development of to the the the a weathered proportions ance has been made for the of each soil body. inherited from parent rock. It is independent This principal genetic the category establishes the if in of the kinds of residual clay; for example, a classes of the New Zealand classification, the names of which, with appropriate modifying adjec- *The word clay is used in the general sense of a residual ofisane pan i tives, are retained in the later categories. The names .the tseuxltuhrejolar c system of distinguished by tprodpuhe of the classes are the suffix -ic- classification but is not itselfa category of the system.

23 2-3

soil from volcanic ash all the argillisable minerals ly. Soil bodies of surargillised soils are more were converted to allophane, the soil would be strongly weathered than those of conformably regarded as fully argillised although allophane argillised soils because they antedate them. Strictly, would not represent the final stage of weathering ’surargillised’ should be applied only where the and with time would decompose to more stable soil body (the complete profile) is retained con- clays. Three main grades are recognised in the tinuously from a former weathering cycle to the field: weak, where only a small proportion of the present day. If an erosion interval has intervened, original argillisable minerals has been decomposed; the remains of the old soil body are more correctly parent moderate, where much has been decomposed but regarded as merely the surargillised material much still remains; and strong, where few of the of the present one. Since it is often impossible to argillisable minerals remain. This scale (or a tell to what extent erosion has occurred, and since more detailed one when available) can be used to the horizons even of incomplete old soil bodies make phases where required for special purposes. can strongly affect the development of present is At this level in the classification, the above day soils, a convention is adopted: a soil said part, criteria are used to assess the relative grade of to be surargillised, at least in if a recognisable argillisation of the soils within the soil regions of depth of the old soil body remains; if, however, each zone. Having regard to broad differences in the material of the old soil body has been trans- parent rocks, standards are obtained by observing ported from its original site, continuity is broken is the grade of argillisation on sites where neither and the new soil formed upon this material erosion nor accumulation is abnormally active regarded as being derived from a new sedimentary and argillisation has reached a maximum conform- deposit of pre-argillised materials. Subargillised able with the particular moisture region of the soils naturally tend to have soil bodies similar in zone. If moisture is adequate these standards are: many respects to those of conformable soils of weak, in the subantarctic; moderate, in the tem- cooler zones where argillisation is weak, and sur- perate; and strong, in the subtropic and tropic argillised soils to those of warmer zones where zones. Each standard represents the maximum argillisation is strong. grade of argillisation that has developed within In Category III of the classification the grade of the particular region since the last zone-wide argillisation where not conformable with that of prefixes soil-destroying catastrophe; it is considered wholly the zonal region is indicated by adding the in relation to the present position of the zones sub- and sur- to the class names as illustrated in prefixes precede (whether latitudinal or altitudinal) and is the the tabulation below; these zonal consequence of the fluctuating climate of the zone. prefixes which in turn precede amo- or oxi- which Differences in the standards are strikingly illus- denote kind of argillisation. The divisions into trated by the great difference in overall clay subargillised, conformably argillised, and sur- possible content of soils in the humid temperate compared argillised are applied in the broadest with humid subtropic and tropic regions. manner in this category, but it is sometimes neces- Not all soils are conformably argillised-some sary to split the subargillised soils into the younger are markedly less (subargillised) and some more and the older subargillised soils in the tropic and (surargillised). Many subargillised soils arise from subtropic zones because of the wide range of local disturbances later in time than the last weathering they embrace.* has zone-wide catastrophe; others occur in places In those parts of the tropics where time where the rate of erosion or accumulation is not been zonally interrupted, many soils have sufficiently rapid to rejuvenate the soil continuous- passed beyond the stage of strong argillisation

CATEGORY III

CATEGORY II Technical Argillisation names Common names Dominant kind Grade

Fulvic Temperate yellow-brown Layer silicates Moderate soils earths (conformable) Subfulvic Temperate yellow-brown Layer silicates Weak soils sands, etc. (Pro-) Fulvous Surfulvic Temperate preweathered Layer silicates Strong soils soils yellow-brown earths

Alvic Temperate yellow-brown Amorphous Moderate soils loams (conformable) Subalvic Temperate yellow-brown Amorphous Weak soils pumice soils

24 I

0 0 34 20

10

50 Egmon

oc Mt

Hettor 60

Mt Victoria

705 605 6 50S 30S 20S ’ 10S LATITUDE c40S

P Upper iimit of flowering plants Upper limit of continuous cover of woody plants - O Scattered plants S Scrub SF Scrub forest (subalpine & subantarctic)

D Discontinuous vegetation (alpine felifield etc.) F Montane forest and lower lying vegetation Herbfleld H (including subalpine tussock etc.)

Tropic (per) .

(ad- (pro-. Subtropic and elevated equiva ent and elad-) Temperate and elevated equivalent and elpro-)

1 ( ) (e- Subantarctic and elevated equivalent (subalpine)(de-&elde-) Antarctic and elevated equivalent alpine) and ele-)

FIG. 2-3-2- Mean annual temperatures (oF), main temperature zones, and associated vegetation of the

New Zealand sector about longitude 1700 E. 2-3

Relative potential ’s 9 rate of argillisation in zones Grade of argillisation ? of soil .9CES skeleton on oE 3

( < m Temperate Subtropic Tropic (1) (6) (20) (33) (60)

Non I -20 O

...... -:.-:::..-:...... *...... *.. Weakly 0-9 70 4

......

Moderately 0- 5 0 5 10 17 30

Strongly 00

* Scale exaggerated x 6

Conformably Subargillised Younger . a IIssed Surar illised soils Older

FIG.2-3-3- Indices of relative rates of argillisation of conformably argillised, subargillised, and surargillised soils in the main energy zones.

processes Hoff’s for and have reached a stage where the of applying van’t temperature rule the chemical weathering are directed predominantly rate of chemical reaction* and assuming other towards the destruction of colloids and the forma- factors to be constant. In humid regions a crude for tion of aggregates with weak or no colloidal index of the rate of argillisation a stated set properties. Some have reached the critical stage of conditions may be derived by multiplying the by where their dominant colloids become irreversibly potential rate of argillisation of the soil the be aggregated when dehydrated. Such old soils may proportion of minerals remaining to argillised grade; indices derived in be regarded as supra-argillised since their mineral as indicated by the this skeletons are passing beyond the phase of clay wayarepresentedinFig.2-3-3. formation into a phase of reaggregation. In the Although the indices are approximate, they New Zealand sector they occur in small areas bring into relief the extreme importance of the only. processes of argillisation in tropic and subtropic grade in The value of adopting as a criterion the soils, and indicate why soil workers the tropics of argillisation in relation to the climatic zone is have tended to think of their soils in terms of evident since it influences strongly the flow (from weathering, whereas workers in temperate regions from rock minerals in the soil skeleton) of new mineral think in terms of modifications stemming the greater elements available for the cycling processes of the organic regime. It shows clearly the sig- organic regime, the relative rate depending on the nificance of tropic subargillised soils which are kinds and physical condition of the rock minerals, weakly weathered but strongly weathering, and on the moisture and temperature of the soil, and on other factors of the soil environment. An ap- proximate idea of the relative potential rate of argillisation in the various zones can be obtained edh ocit’lo9f4al,cp3 from mean (Fig. 2 3 by The ruleievegnlr02nsbrinteamperatis empirical and is approximate only. the temperatures - -2)

25 2*3 indicates why the most significant single soil The skeliform classes are subdivided according boundary in these regions is that between the to the rejuvenating processes of the drift regime. subargillised and conformably argillised soils (Fig. In many soil classifications based on the more parts processes 2-3-3). It explains the persistent attempts to sub- stable of the earth’s surface, these divide tropic soils genetically into monocyclic and are not recognised as soil-forming; but, as indi- polycyclic soils at the highest level of classification cated above, where they modify the soil system (von Klinge, 1956; Fink, 1956). It also directs without actually destroying it they are necessarily attention to the differences in approach necessary an integral part of the soil-forming processes. in tropic and temperate regions when considering Thus the skelous soils are divided into the problems of degrading and regrading soils. luvic, volic, clinic, regic, and lithic soils as folloWS: ACCUMULATION, REMOVAL, AND hilXING

The organiform and skeliform classes of Cate- CATEGORY III gory II, which do not show developed horizons, CATEGORY require different treatment from the other soilS II Technical Common names and are subdivided according to the kinds of names and processes processes (such as accumulation and rejuvenating Luvic Recent soils rejuvenating by removal) that oppose the formation of developed soils water-borne accumulation horizons Volic Recent soils rejuvenating by

The . organiform classes are subdivided accord- soils air-borne accumulation ing to the broad processes that govern the accumu- (Pro-) Skelous Clini Skeleudmoiltsdrejune ting by lation of the organic matter and determine in part its composition and the extent to which it is admixed with mineral material. Thus the organous Regic Regosols not rejuvenating - soils soils form quickly soils are divided into lodic and platic soils as follows: Lithic Lithosols not rejuvenating

- soils soils form slowly

CATEGORY III Category II Technical Common Nature of Accu- Luvic soils are continually being rejuvenated by names names mulation additions of alluvial material on the surface; with intergrades Lodic Blanket peats Climatic their to associated non-skeliform soils (Pro-) soils (Ombrogenous) they are dominant on flood plains and fans. Organous Volic soils include soils around active volcanoes Platic Concave basin Local the period- soils peats (Soligenous and where thin layers of volcanic ash are added Topogenous) ically to the soil surface, the soils adjacent to flood plains where loess is actively accumulating, and the soils adjacent to sand drifts which con- Lodic accumulations are climatic or ombrogenous. tinually receive additions of wind-blown sand. They are consequent on suitable conditions or Clinic soils show little or no profile differentiation, particular rainfall and temperature, and. cover other than melanisation of the topsoil, because climatic regions of the earth’s surface. They are they are continually being rejuvenated by removal, modified by, but do not result from, local condi- accumulation, and mixing consequent on colluvial tions of topography. Platic accumulations on the movement downslope. For specially detailed stud- other hand are local in distribution and occur ies, they may be divided into phases according to where normal decomposition in the zone is slowed the dominant process (regressive or accumulative down owing to local conditions of topography, clinic soils); and where necessary this principle ground soil, and high water. For the most part, may be used to subdivide other classes. The regic they occur in humid regions in basins where the and lithic soils have little or no profile develop- ground water is close to the surface, but they are ment because insufficient time has elapsed since not confined to such regions. They include also the inception of soil formation rather than because the small patches that form near springs and of soil-rejuvenating processes. The regic soils are seepages. In general they are higher in mineral formed on drifts of fine texture. Where soil forma- matter than are the lodic accumulations. The soils tion is rapid, as in warm humid regions, they are of raised bogs which are in part ombrogenous short-lived. The lithic soils occur on hard, massive and in part soligenous or topogenous, are regarded rocks and coarse drifts (such as lava flows and as intergrades e.g. lodi-platic soils. moraines) which are so resistant to change that

26 2.3 they persist for a long time without the formation to a fulvic soil, a fulvi-clinic soil is one that shows of evident soil horizons. some fulvic characters but has not the structural B In classifying the eleskelous and the eskelous horizon associated with fulvic soils, and a clini- soils, additional classes are needed, for example, fulvic soil is one that shows the characters of a the gelic and the frigic* soils which are commonly fulvic soil although they are modified by slope stirred by frost action. Gelic soils are found in conditions. In a similar way a podi-fulvic soil is alpine regions where the surface is bare of insu- weakly podzolised and a fulvi-podic soil is moder- lating vegetation. Under these conditions the ately podzolised but retains some fulvic characters surface soil is lifted by frost and, following the especially in the subsoil. For conciseness it is thaw, its finer fractions tend to be blown away unnecessary to repeat zonal prefixes; thus a fulvi- leaving a stony surface layer or pavement. Frigic alluvic soil is an intergrade between the northern soils, which occur in antarctic regions where stir- rapidly accumulating recent soils from alluvium yellow-brown ring by frost is prevented in many places by and the northern earths. dryness, have subsurface permafrost. Where it is desired to indicate that the soil is In some small areas in the temperate regions of an abnormal intergrade resulting from the burial New Zealand the soils have little or no profile of the whole or part of a former soil the connecting place development owing to continuous mixing by vowel o is used in of i. Thus for a composite organisms. They are classed as bioturbic soils. soil, the upper part of which is formed from fresh They are best illustrated in the nesting areas of alluvium and the lower part from concave basin burrowing sea birds where, besides being thor- peat, the name luvo-platic is used to distinguish inter- oughly stirred, they are enriched by droppings. it from a luvi-platic soil which is a normal peat In the New Zealand sector (outside the antarctic grade formed from a mixture of and alluvium. and alpine regions) skeliform soils are for the Similarly a fulvo-surfulvic soil is a composite one, most part very much less extensive than their the upper part being derived from soliflual or intergrades to associated soils. In humid temperate glacial material (conformably weathered) and the regions, for example, soils on steep slopes are lower part from an older surweathered soil body. mostly intergrades to fulvic soils-and are not SEQUENCES OF PRINCIPAL CLASSES ACROSS THE solely clinic soils; and similarly the luvic and DIVISIONS OF CATEGORY 11 volic soils are generally much less extensive than To arising from use of their associated intergrades since accumulation avoid confusion the the precise definition, over wide areas is rarely so fast that it prevents technical names outside their refer the partial expression of basal forms other than suitable adjectives are on occasion needed to soils skeliform. collectively to the sequences of corresponding that cross the climatic zones, that is, to express SOIL PHASIC SUBDIVISIONS BASED ON hiOISTURE soil body form at the level of Category III. Such formed by As described under Category II, phasic sub- adjectives may be adding the sufHx stem of class name, for example categories based on soil-moisture classes are -oid to the the perluvic, (pro-)luvic deluvic soils applied at the level of Category III as needed, the alluvic, and be luvoid and are expressed directly or indirectly as outlined may regarded collectively as soils, and etc. in section 6 of this chapter. For agronomic purposes other sequences as alvoid, spadoid, this is also a convenient level of classification to introduce phases detailed other that express more CATEGORY IV climatic conditions so important when grouping Horizon Development soils for land use. In Category IV the classes of Category III are NAMING INTERGRADES OF BETWEEN THE divided according to the salient remaining morpho- PRINCIPAL CLASSES logical differences, which are interpreted in terms The names of intergrades at the level of Category of the kind and degree of the processes that have III are derived by compounding class names. The produced them. Such processes fall into two stem of the subordinate name, with the connect- groups-those that lead to, and those that tend ing vowel i is linked by a hyphen to the full name to retard, the development of ordinary soil hori- of the class that the intergrade most closely re- zons. sembles. Thus, in the progression from a clinic The effects of the first group of processes include the kind and degree of illuvial development in the soil (such as arise from illimerisation, podzolisa- *Since elegelic and soils are limited in the efrigic very their tion, and in a few soils desalinisation) and the geographic range the zonal prefixes may be onutted where degree gleying of soil horizons. the meaning is clear. of

27 2-3

The degree of clay illuviation is subdivided as the state of enleaching in a general way expresses follows: weakly clay illuvial-search reveals patchy the nearly steady state due to near equilibrium clay skins on peds and in some pores; moderately between the rate of weathering, the rate of leach- clay illuvial-distinct accumulation of clay in the ing, and the efficiency of the organic cyclic return. subsoil, clay skins tend to be continuous but It is not identical with, but is approximately textural differentiation not marked; strongly clay indicated by, the degree of salinity and the per- illuvial-marked textural differentiation with erod- centage base saturation of the soil, which are the ed peds in upper horizons and continuous clay criteria used for classification. It may be applied skins below. to the soil as a whole or to individual horizons, Other kinds of illuvial horizons (for example in but unless otherwise specified refers to the average podzolised soils) are referred to as humus illuvial for the solum. The classes of enleaching other or iron illuvial, etc., or, as in the case of related than saline and their approximate correlation formations, by referring directly to the formation with percentage base saturation are: weakly (over itself (e.g. ’with concretions’, ’with fragipan’). 50), moderately (30-50), and strongly (less than Fragipans may be incipient, or well developed, 30) enleached. Where needed, the subclasses very and may be subgammate, gammate, or net- weakly (70-100) and very strongly (0-15) are also gammate. separated. The degree of gleying may be referred to indi- vidual horizons or to the soil as a whole; unless CATEGORY VI it B otherwise stated, refers to the horizon where Parent Material it is common. Gleying may be diffuse or most in In Category VI the soil classes are divided. . spot: diffuse or complete gleying is the kind com- effect according to those combinations of soil monly occurring in the As horizon of gley podzols; properties due directly or indirectly to differences spot gleying (Kanno, 1957) found in the B horizons in parent materials and not already used in higher of many soils, is subdivided into weakly (less than categories. In addition to its more obvious effects, 2%), moderately (2 20%), and strongly gleyed - parent material Introduced at this level differenti- (more than 20%). ates many intrinsic soil properties inherited directly The effects of the second group of processes, or indirectly from the parent rock such as those which tend to retard the development of soil hori- of value in the study of trace element distribution. zons, such as erosion and accumulation and those The names of the soil classes reflect these causal giving rise to mixing, are treated in a similar way, relationships as in the examples ’from strongly particularly for the skeliform soils and their inter- argillised greywacke’ and ’from comminuted schist’. grades as in ’slowly accumulating luvic soils’. When making main divisions in Category IV CATEGORY VII the use of an unqualified morphological term Surface or Subsoil Horizons implies moderate to strong expression of the gleyed, characteristic. Thus clay illuvial, and other The final category of the classification is sub- qualification, terms, when used without are under- divided according to texture, the organic profile, stood to connote ’moderately to strongly clay and modifications (including those due to man) illuvial’ in illuvial’ contrast to ’weakly clay and that affect portions of the soil profile but do not so on. affect the whole soil strongly enough to be ex- pressed in higher categories. Commonly of is given CATEGORY V the texture the topsoil but it may be supplemented as necessary by the State of Enleaching texture of the subsoil, for example, ’sand on clay’. Category V is based on the state of enleaching, The organic profile of many topsoils is subject which is the balance of the incoming and outgoing to rapid modifications following changes in the mineral ions in the active fraction of the soil body. vegetative cover, whether natural or man-induced. Incoming elements arrive from the weathering Consequently, as a differentiating character of the soil skeleton, from the cyclic return of the organic current soil system, it is introduced into the regime, and from additions by way of the drift classification at this low level, its more stable regime. Outgoing elements are leached away by effects having already been covered in, the higher downward and laterally moving water, some are categories. It is classed as peaty, moroid, or lost by erosion, some are immobilised by recon- mulloid, and is characterised in greater detail stitution in the soil body, and some are withdrawn by adjectives expressing structure and consistence by organisms for varying periods. as is done for forest soils by Bornebusch and grassland Where the effects of the drift regime are small, Heiberg (1936). In soils, it is termed

28 2-4 the sod. For example, three organic profiles de- E-: see Zonal prefixes El-: contraction of elevated veloped under pasture at different levels of manage- Enleaching: en-(L. in- forming verbs from adjectives, etc. (Taylor, 1955, p. 963) be ment may classed aS bring into this condition)+1eaching = to moroid sod, strongly fibrous mulloid sod, and Fragipan: from ’Soil Survey Manual’ (U.S. Soil Survey Staff, 1951, p. 243); L. fragilis= brittle weakly fibrous mulloid sod.* In absence of the Frigic: L. frigus= cold detailed information differences in the organic Fulviform: L. frdrus= yellow, yellowish brown, reddish profiles have commonly been indicated in a broad yellow, etc. Gammate: Gk. gamma (y) way by reference to the vegetation that has pro- Gelic: L. gelum= frost duced them, as in the examples, ’scrub melanised , Hydrous: Gk. hudor= water ’tussock and melanised’. Hygrous: Gk. hygros= wet Where modifications due man or other agents L. (connecting to -i-: vowel) L. icus (forming adjectives) change both topsoil and subsoil sufficiently, they -ic: Fr. from L. formis=having higher -iform: -i-+-form; -forme the are classified systematically at appropriate form of (e.g. cruciform) levels intergrades. of the classification or as Where, Latiform: from latosols; L. Iater=brick however, modifications affect only the topsoil or Lithic: from lithosols; Gk. lithos= stone c dix aoblanket affect partially conditions in other horizons they are best expressed at low level of Category VII. the Madentiform: L. madens= wet, marshy Thus in fulvic soils of Southland have been Melanisation: Gk. black that melas -anos= heavily limed and support high-producing pastures Nigriform: L. niger=black, dark Gk. like. Used in sense of ’having form of’ it is the topsoils that are enriched and markedly -oid: -oeides= the Organiform: from organic soils modified, have whereas the subsoils remained L. abounding in (Chem.= with larger propor- -ous: -osus= little altered even in their level of enleaching. tion of the element indicated by the stem than those ending in -ic, e.g. chlorous acid) Oxadic: contraction of oxi+spadic DERIVATION OF TERMS Oxi-: Prefix indicating crystalline oxide clays Ad-: see Zonal prefixes Palliform: L. pallor=paleness Alvic: contraction of amo+fulvic Permafrost: from ’Soil Survey Manual’ (U.S. Soil Survey Amadic: contraction of amo+spadic Staff, 1951, pp. 181, 184);=permanently frozen ground; Amo-: prefix indicating amorphous clays ?contraction of permanent+frost Argillisation: from geology O.E. plat= flat (secondary alteration to clays) Platic: Podiform: from podzol Bioturbic: Gk. bios= life, L. turbare= to disturb es Clinic: Gk. klino= slope "" " De-: prefixes see Zonal Regic: fromZonatreregosols Drift: from geology (superficial deposit made by current of Sitiform: L. sitis= thirst, dryness water or air) Skeliform: from skeletal soils Soloniform: from solonetz Spadiform: L. spadus= reddish brown *The terms mulloid and moroid are used (in place of mull Sub-: L.= under, below form and mor) where they refer to the of the whole organic Supra-: L.= beyond profile as a unit. In mulloid profiles the bulk of the organic Sur-: L. super=above matter is incorporated with mineral soil, and in moroid the Volic: L. volare= to fly is it profiles it for the most part unmixed and enough of Xerous: Gk. xeros= dry accumulates to produce F and H horizons, which lie above the mineral soil. The terms mull earth, moder, and raw Zonal prefixes: humus are used for particular kinds of organic matter Per-: completely, thorough the = (with within the various horizons of the organic profile. The terms Ad-: L.= up, to connotation of ’changing to’) mull and mor are avoided since in the present confused Pro-: L.= in front of, in favour of state of terminology they are used both for the kinds of De-: L.= down (contrasted with ad-) organic profile and the kinds of organic matter. E-: L.=ex=out of

2-4- GENETIC NAMES

for pressed Genetic names soils emerge from the criteria and omitting terms that are subordinate or applied to them under the various categories. To redundant. Usually, for example, the state of give each criterion its appropriate connotation, enleaching need not be given for podic or latic it is terms derived from Categories III to V and also soils where almost always strong; ’fragipan’ it indicated those from VI to Vll are reversed in order; that need not be included where is to- is those from Category V are given first and gether with its form by the term gammate; and followed by those from IV and III and, where clay illuvial, gleyed, or other terms of Category IV applicable, VII and VI. The complete names are that imply well expressed characters need not be generally long, but simpler names are derived qualified. If Table 2-4-1 be taken as an approxi- by omitting characteristics that are weakly ex- mate analysis to Category VI of five common soil

29 2*5

TABLE 2-4-1- Genetic Analysis of Five Common Soils to Category VI

Category III Category IV Category V Category VI

Soil Name Principal Illuvial Notes on Pans, Gleying Enleaching Parent Material Class Horizons Concretions, etc.

Okaihau gravelly Latic Many concre- Very strongly From strongly argill-

. . . . friable clay tions (Fe, Al) enleached ised basalt

Taupo sandy silt Subalvic Moderately From rhyolite

.. . .. enleached pumice

Taita clay loam Surfulvic Moderately Strongly From strongly argill- clay illuvial .. .. enleached ised greywacke

Timaru silt loam Pallic Weakly clay With gammate Weakly Moderately From moderately illuvial fragipan gleyed enleached argillised loess

Conroy gravelly Sitic Moderately Very weakly From comminuted sandy loam clay illuvial .. .. enleached schist

types, the simple genetic names are: Different kinds of podzols are readily distin- Okaihau gravelly friable clay: concretionary guished at the level of Category IV. For example, latic soil from strongly argillised basalt among the various kauri podzols, the Wharekohe Taupo sandy silt: moderately enleached sub- silt loam is a ’B-gleyed clay illuvial appodic soil’, alvic soil from rhyolite pumice Te Kopuru sand is a ’humus iron illuvial appodic Taita clay loam: strongly enleached clay soil’, and the ground-water podzol bordering illuvial surfulvic soil from strongly argillised Lake Ohia is a ’humus illuvial madenti-appodic greywacke soil’. The rimu podzols of the Rangitoto Range Timaru silt loam: moderately enleached gam- developed from Taupo pumice are ’humus iron mate pallic soil from moderately argillised illuvial subpodic soils’. Common gley podzols loess are ’A-gleyed iron illuvial podic soils’. Conroy gravelly sandy loam: weakly en- On the other hand, should it be necessary, names leached, clay illuvial sitic soil from com- may be amplified and extended to Category VII. In minuted schist a paddock near Kihikihi, for example, the modified For many purposes the names are further simplified Otorohanga silt loam (a yellow-brown loam from by expressing them to Category V and phasing Mairoa ash) is in full a ’moderately enleached, after the parent rock type, for example, the Taita very weakly clay illuvial, alvic silt loam with enrich- soil is a ’strongly enleached moderately clay ed weakly fibrous mulloid sod-from moderately illuvial surfulvic soil after greywacke’. argillised mixed rhyolitic and andesitic ash’.

2*5* THE CLASSIFICATION ZONALLY ARRANGED

In the early years of the Soil Survey the multi- dominantly intrazonal or azonal, or as intergrades. plicity of units and the many confusing ideas This arrangement has proved most valuable about their classification led to attempts to arrange for demonstrating and helping to understand soil the soils zonally in an endeavour to get some main relationships and is still a useful method of presen- threads of order. In effect this represented an tation, but it is not a necessary part of the classi- attempt to classify the soils keeping certain factors fication. It is no more than a special arrangement constant. It was based on Marbut’s definition of a of the classes of Category III. The classification ’normal site’ (in Krusekopf, 1942), which, however, may be zonally arranged in two main ways-first, was modified to exclude not only steep land and by arranging the soil classes in zonal, intrazonal, hollows but also extremes of parent rock such as and azonal groups, and secondly, by arranging limestone and basalt, granitic composition being zonal soils and their associated intrazonal soils taken as the norm. The soils on such normal sites in groups according to the various zones. A zonal were called zonal since they occur in a clear zonal arrangement of the classification is illustrated in pattern. In this way, differences due to various Table 2-5-1 in which the main soils of the New miscellaneous factors were set aside, and Zealand soil map in ’A Descriptive Atlas of New differences due to climate and vegetation were Zealand’ (McLintock, 1959) are given with their allowed to emerge. Other soils were regarded as common and technical names.

30 2*5

TABLE 2-5-1- Modified Legend of the New Zealand Soil Map (McLintock, 1959) with Common and Technical Names in a Zonal Arrangement

Related Steepland Complexes Common Names No. on Technical Names Legend Common Names No. on Technical Names Legend

ZONAL SOILS Brown-grey earths 1 Sitic soils Steepland brown-grey 17 Co-sitic steepland soils earths (mainly siti-clinic, clini- sitic, co-sitic clinic soils) Yellow-grey earths 2 Pallic soils Steepland yellow-grey 18 Co-pallic steepland soils earths (palli-clinic soils, etc.) association 2r -in with -with nigric soils, calcareous soils etc. -related shallow and 2g -co-palliefulvicsoils stony soils with stony subsoils yellow- High country 3 Eldefulvic soils High country steepland 19 Co-eldefulvic steepland brown earths yellow-brown earths soils (fulvi-eldeclinic soils, etc.) Subalpine gley soils and A-gleyed eldefulvic and Subalpine steepland gley 20 A-gleyed co-eldefulvic and gley - podzols podzols eldepodic soils soils and gley co-eldepodic steepland soils (A-gleyed fulvi- eldeclinic soils, etc.) Southern and central yel- 4 Fulvic soils Southern and central 21 Co-fulvic steepland soils low-brown earths steepland yellow- (fulvi-clinic soils, etc.) brown earths Southern and central pod- 5 Fulvi-podic and podic Southern and central 22 Co-podic steepland soils zolised yellow-brown soils steepland podzolised (fulvi-podi-clinic, podi- earths and podzols yellow-brown earths clinic soils, etc.) and podzols Gley podzols 6 A-gleyed podic soils Northern yellow-brown 7 Affulvic soils Northern steepland 23 Co-affulvic steepland soils earths yellow-brown earths (fulvi-acclinic soils, etc.) 7r -in association with cal- -with annigric soils, careous sails etc. Northern podzolised yel- 8 Fulvi-appodic and ap- low-brown earths and podic soils podzols -mainly sandy with well 8s -mainly sandy hu- developed pans and mus iron illuvial associated with peaty appodic soils with soils applatic soils

INTRAZONAL and AZONAL SOILS Yellow-brown sands 9 Subfulvic, subaffulvic soils, etc. Yellow-brown pumice soils 10 Subalvic soils Steepland yellow-brown 24 Co-subalvic steepland soils pumice soils (subalvi-clinic soils, etc.) Yellow-brown loams 11 Alvic soils prospadous, Brown granular loams and 12 Spadous, Steepland brown granu- 25 Co-spadic and co-oxadic clays and red and brown and latous soils lar loams and clays steepland soils (spadi- loams and red and brown acclinic, co-oxadic ama- loams di-acclinic soils, etc.) Organic soils 13 Platic, lodi-platic, ap- platic soils, etc. Gley soils 14 Madentic and adma- dentic soils Recent soils from alluvium 15 Luvic, fulvi-luvic, allu- vic soils, etc. 15w -with swamps -with madenti-luvic soils Recent soils from volcanic 16 Volic soils from vol- Steepland recent soils 26 Co-volic steepland soils ash canic ash from volcanic ash from volcanic ash (voli- clinic soils from volcanic ash, etc.) Steepland brown-grey 17 See related steepland earths, etc. to complexes on right 26

Alpine soils 27 Gelic (geli-elecli soils and co-gelic steepland soils lic soils, -tc.)

31 2-6

2*6- USE OF SOIL-MOISTURE CLASSES IN PHASIC SUBDIVISIONS

on Where do adequately express dominates over white clover, and the moister the soil classes not s sui te clodver and rye atreo ta it is neces- the moisture regime of the soil system, d 1soilsn phasic be by low-producing annual sary to introduce subdivisions for this tend strongly to replaced clovers-suckling in South Island, and subterranean, purpose. A convenient method of applying these clustered, and striated m North Island. The charac- is in phasic yellow-grey subdivisions the form of subcategories teristically subhygrous soils are the earths Categories II pronounced dry season. of the classification at the levels of with a or III, but, being phasic, they are used only as 4. HYGROUS does not reach wilting point necessary. The soil on the average rt y month and i edfie capac ts mostbo all The between climate and soil moisture relation sfo5 is analysed by Thornthwaite (1948) in arriving at field capacity for one to five months and the moister hygrous soils are above field capacity for all months. water balance for drained soils. On the assump- the The moisture is adequate for good permanent pastures have tion that most soils a water-storage capacity based on ryegrass and white clover. Characteristically yellow-brown podrols, of 4 in., the water supply from monthly rainfalls hygrous soils are the earths, the and many soils affected by moderately high ground is balanced against potential evapotranspira- the water. They are commonly associated with a humid

be . in tion, which can calculated approximately if climate, the lower limit of annual rainfall the south 30 in, in north about latitude is known and temperature records are being commonly about and the in 40 in. available. If allowance be made for differences SUBHYDROUS run-off (particularly on sloping land) and for 5. from ground water, it is possible accessions the av r e sitm fihae t; r 3eh re periods de- (near mTn in this way to estimate the of water it is above field capacity and over-wet saturation). Characteristically such soils occur in places with heavy ficiency soil moisture is below wilting when the m point, periods and the of water surplus when the p un se so Su c io Tpd r ed in Fiji, moisture is above field capacity allowing water to on the western side of Viti Levu and on other Pacific Islands. drain through and leach the soil. Between these 6. HYDROUS extremes are periods when the moisture there stoil avera sd btove fie}d cap ity in soil is being drawn upon or is being % stored the allThe tthhe recharged. The moisture regimes for 113 stations above field capacity and over-wet for long periods. It is pugging by stock at most times of the in New Zealand sector are analysed by Cox susceptible to the year. Characteristically hydrous soils include the in section 7 of this chapter. yellow-brown earths and podzols of medium and heavy with ground In an attempt to arrive at suitable soil-moisture texture in superhumid regions and soils water at or near the surface. classes for New Zealand, a soil rating based on pasture performance was proposed by Messrs Under the same climatic conditions soils of S. H. Saxby and R. H. Scott (pers. comm.), and in general half class drier coarse texture are one calculated water balances were re-examined Thus Lismore the than those of medium texture. using actual storage capacities in drained and classified stony loam and the associated well soils for depth of 18 in, in place of the soil a theoretical of finer texture are subhygrous, the Lismore (McDonald, Chapter 9-3). In way ones this the belonging to the drier part of this class and the following classes emerged: part. soil-moisture others to the moister Similarly, the sandy have for DRY CLASSES Soils of the Manawatu coast the most XEROUS 1. part subbygrous moisture regimes, whereas the The soil is on the average below wilting point for all yellow-brown earths and gleyed yellow- months of the year. Desert conditions prevail. Except associated mp t of tlhe Antc%ctic, the class does not grey earths of finer texture have moisture regimes perha% drier part hygrous class. that belong to the of the 2. SUBXEROUs In superhumid West Coast district of South The soil is on the average below field capacity for the hydrous or each month and below wilting point for six months or Island most soils of fine texture are but not all year. In pastures, ephemeral plants more the nearly so, whereas the coarser textured soils, are favoured, for example, haresfoot trefoil, hairgrass, more rapid internal drainage, and brome. The class is characteristic of the soils of because of their semi-arid regions, such as the brown-grey earths, which are hygrous. average are at wiltmg pomt for six or seven on the In some arrangements of the soil classification, months of the year (between October and May) and legends maps, have annual rainfall commonly of 15 in. or less. notably on the of some soil the particular MoIsT CLASSES apprOximate moisture class for soils 3. RO has been indicated indirectly by noting below field for their Te O n the average capacity with a soil has a characteristic more than five months of the year and below wilting association that diffi- ’as- point for one to five months. There are resultant moisture regime. Thus rendzina-like soils mamtaining white clover; on the drier sub- culties m with yellow-brown earths’ and those hygrous soils subterranean clover commonly pre- sociated

32 2-7

’associated with yellow-grey earths’ are indicated portant to appreciate that they express soil mois- as falling into different moisture classes. The ture only and are not a substitute for the more association of one soil with another, for this or detailed characterisation of the soil body as for any other reason, can be conveniently ex- required in the lower categories of the classifica- pressed with an adjective formed by prefixing co- tion. For example, the Okarito soil of Westland podic to the technical name of the soil class selected as is correctly classed as a hydrous soil at the but, however appropriate for the purpose in hand, for example, level of Category III, strong the co-fulvic nigric soils and co-pallic nigric soils. implication, it is not definitely indicated as a gley podzol In applying the soil-moisture classes it is im- until it has been classed in Category IV.

2-7- EVALUATION OF CLIMATE AND ITS CORRELATION WITH SOR GROUPS

by J. E. Cox

periods differ In this section the climate at stations in the 1921-1950 and substantially at many New Zealand sector has been evaluated. The sta- stations from the long-term averages used by have been less tions have been arranged in climatic classes that Garnier and Hurst. Temperatures for are closely related to the main soil groups and ex- affected by this revision; many stations they press the relation between precipitation and the are averages revised to 1950, but about one-third water needed for evaporation and transpiration- of the stations have short records mainly taken a relation that determines to a large extent the since 1950, and, for these, normals have been kind of soil developed. worked out by the Meteorological Service. Because Thornthwaite’s classification (1948) has been the revised rainfall normals place stations on a applied to New Zealand by Garnier (1951) who fairer basis for comparison, Thornthwaite values produced maps showing the distribution of the for all stations have been recalculated using the present climatic types. Garnier gave tables of values for revised data. From Hurst’s work and the selected stations for the various Thornthwaite study it appeared desirable to modify the bound- indices. He was satisfied with the way the classifica- aries of the moisture types defined by Thornthwaite, tion differentiated the major moisture types of the and this fact, coupled with the revision ofmeteoro- country but proposed one modification to indicate logical data, has limited the use that could be seasonal contrasts in effective moisture in the made of Garnier’s work, though his remains a drier parts of New Zealand. Concerning tempera- most valuable reference. ture divisions he thought the system unsatisfactory in not differentiating sufficiently between north ELEMENTS OF and south, the only major contrasts being those THORNTHWAITE’S CLASSIFICATION (1948) between the mesothermal climates below an elevation of 2,500 ft and the microthermal and Potential evapotranspiration is the amount of colder climates above. moisture lost by evaporation and transpiration Hurst (1951) compared Thornthwaite’s classifica- from the soil when it is covered by vegetation From tion (1948) and several others to rate their success and amply supplied with water. study of projects from in distinguishing between the climates prevailing rates of water use in irrigation and (1948) in the yellow-grey earth (pallic) and yellow-brown catchment run-off records, Thornthwaite found ’When for earth (fulvic) zones in New Zealand. She con- that adjustments are made gave day is cluded that Thornthwaite’s classification the variation in length, there a close relation potential best differentiation between the soil groups on the between mean monthly temperature and data basis of moisture status, and on several counts evapotranspiration. Study of all available in formula permits judged it the most useful. On the other hand a has resulted a that the compu- potential place study of Hurst’s data shows that Thornthwaite’s tation of evapotranspiration of a moisture types do not correlate well with the if its latitude is known and if temperature records soil groups because the moisture indices chosen are available.’ formula, to separate the moisture types do not correspond Water need, calculated according to the well with the moisture indices that differentiate is balanced against the supply from rainfall. (1951), is the soil groups. According to Hurst when rainfall equal field Since the work of Garnier and Hurst was to water need, the soil is maintained at place. When published, the Meteorological Service has revised capacity and no leaching takes the rainfall and temperature normals for all climate supply is greater than the need there is a surplus stations. The rainfall normals are for the 30-year for leaching the soil. When it is less the soil mois-

33

C 2-7

ture in the root zone* is drawn upon until wilting Thus in an overall moisture index the [surplus] point is reached. After this there is a water defi- has more weight than the [deficiency]’. ciency. At the end of the dry season the reservoir The relation between water surplus (s), defi- of soil moisture must be filled to field capacity ciency (d), water need (n), and the moisture index before there can again be a surplus. According to (MI) is: Thornthwaite (quoting the original text except 100s 60d - ’Although . MI* where indicated), a water surplus in n ~ one season cannot prevent a deficiency in another The thermal eficiency at a station is indicated except as moisture may be stored in soil, potential the to by the evapotranspiration for the year for a certain extent one may compensate the other. (PE*). As Thornthwaite stated, ’Potential evapo- Water surplus means seasonal additions sub- to transpiration is an index of thermal efficiency. It soil moisture and ground water. Deeply rooted possesses the virtue of being an expression of day perennials may make partial of use subsoil mois- length as well as of temperature. It is not merely and minimize effect of drought. growth ture thus the a index but expresses growth in terms of Transpiration proceeds, but at reduced rates. For the water that is needed for growth. Given in the reason a surplus of only 6 inches in one season this same units as precipitation it relates thermal will counteract a deficiency of 10 inches in another. efficiency to precipitation effectiveness.’ In Table 2-7-1 values of potential evapo- transpiration and a balance sheet of moisture for Blenheim are given as an example. The moisture *Thornthwaite (1948) stated that except in areas of shallow index is 2-4 and index (PE) soil the water storage capacity available to mature plants the thermal-eficiency 4 varies around a mean that is the equivalent of about in, is 26-6 in. The station is typical of the climate in of rainfall. At that time he believed all this stored water to yellow-grey be equally available, and he calculated water-balance sheets which the earths are situated. preparation on this assumption. Later (Thornthwaite and Hare, 1955) It is assumed in the of balance he suggested a more in more complex relationship which sheets that the rainfall is able to infiltrate into the water stored, but it becomes less easily available as the is soils readily, at least until field capacity is reached; storage becomes depleted. His original assumption is the one used here; the value of 4 in. of available-moisture storage capacity agrees reasonably well with the values given by McDonald (Chapter 9-3) for New Zealand soils *In this section and in the tables and figures, the symbols excluding those that are excessively shallow, stony, or MI and PE are equivalent to Thornthwaite’s Im and annual coarse-textured. PE respectively.

TABLE 2-7* I Potential Evapotranspiration and Water Balance for a New Zealand Climate Station* - According to Thornthwaite’s Classification (1948)

Jan. Feb. Mar. Apr. May Jun. Jul. Aug. Sep. Oct. Nov. Dec. Year

Mean Temperature (or) 62-6 62-8 59-9 55-5 49-6 44-9 44-1 46*3 50-2 53*7 56*9 60*8 $3-9 (oc) 17-00 17*11 15-50 13-06 9-78 7-17 6-72 7-94 10-11 12-06 13-83 16-00 if 6-38 6-44 5-55 4-28 2-76 1*73 1-57 2-02 2*90 3-79 4-66 5-8247-90=If

Unadjusted potential evapotranspiration (in.) 3*04 3*08 2*72 2-19 1-52 1-03 0-95 1-18 1-60 1-99 2-35 2*82

Adjusted potential evapotranspiration(in.) 3-9 3-3 2-9 2-0 1-3 0*8 0-8 1-1 1-6 2-3 2-9 3-7 26-6

Rainfall (in.) 2-0 1-9 1-6 1*9 2-6 2-3 2-4 2-5 2*4 2*5 1-8 1-9 25-8

(in.) 0 0 0 0 0 0 Storage change -1-1 +1-3 +1-5 +1-2 -1-1 -1*8

Storage (in.) 0 0 0 0 1-3 2-8 4-0 4-0 4*0 4-0 2-9 1*1

Actual evaporation (in.) 3-1 1*9 1-6 1-9 1-3 0*8 0-8 1-1 1-6 2-3 2*9 3*7 23-0

Water deficiency (in.) 0-8 1*4 1-3 0-1 0 0 0 0 0 0 0 0 33-6

Surplus water (in.) 0 0 0 0 0 0 0*4 1-4 0-8 0-2 0 0 2-8

Thermal-efficiency index (PE)= annual potential evapotranspiration= 26 6 inches. - (100x2-8)-(60x3-6) 64*0 Moisture index (MI)- 2-4 26-6 26-6

*Blenheim (41o30’S, 173038’E), subhumid mesothermal "1", station typical of yellow-grey earth zone. tSee Thornthwaite (1948) for meaning of i and I.

34 2-7

this requires sites with little slope, soils of good elevation north of latitude 38oS, and a few as far permeability, and rainfalls of moderate intensity. south as 40oS; as defined by Thornthwaite it Where these conditions are not met, some of the covered only scattered pockets in the north of rainfall may be lost in run-off although the soil the North Island. The lower limit of mesothermal is below field capacity. ’1’ was raised so that more of the elevated inland regions of both islands fall into the microthermal instead of mesothermal subdivision. PROPOSED GROUPING OF CLIMATE The indices selected for boundaries of mois- STATIONS INTO CLIMATIC CLASSES the ture and temperature-efficiency classes do not Moisture indices (MI) and thermal-efficiency result in arithmetically uniform divisions. However, indices (PE) have been for 108* calculated stations the moisture index and thermal-efficiency index in New Zealand (Fig. 2-7*1) and 5 on various arebasedonaveragevaluesofrainfall,temperature, islands---Nandi Airport Suva in Fiji (tropics), and etc., but the soil development is probably also Raoul Island in (subtropics), Kermadec Group influenced by certain departures from the average, Waitangi in Chatham Islands (temperate), and and it may be that the boundaries now chosen are Tucker Cove in Campbell Island (subantarctic). sound despite the lack of elegance. Their exact In Fig. 2*7-2-2-7*7, curves comparing water positions as given to a tenth of a unit cannot be precipitation for need and are shown most of made too much of in view of the short term (In these stations. most cases where two stations meteorological observations of some stations, have are very close together and very similar curves, climatic variability at others, and the overall one has been omitted from the figure, but all are need fbr improved soil knowledge. given in Table 2*7-2. The stations omitted from these figures are listed in Table 2-7-3.) Values for moisture index (MI) and for thermal-efficiency SOILS ASSOCIATED WITH THE mdex (PE) are shown near the base of each graph. CLIMATIC CLASSES The in arrangement of stations climatic classes In Table 2-7-5 the climatic classes (including according is to moisture and thermal efficiency the moisture and thermal efficiency classes) are in Table 2*7*2. In shown arriving at this arrange- listed approximately in the order in which they ment, cards for each station, bearing rainfall and appear in Fig. 2*7*2-2-7-7. The soils near the placed in list in water-need curves, were a single climate stations belong to a wide range of soil index (MI) from lowest order of moisture to groups, but it is possible to recognise their zonal highest. The boundaries between Thornthwaite’s groups affinity to one or other of the zonal soil 2*7*4) moisture types (Table were shown. A listed in Table 2-7*5. The soils at each station in group pedologists list of examined this and on each climatic class were listed according to these knowledge in their of soils the neighbourhood of zonal soil groups as summarised in the table: indicated the climate stations they whether or where only one soil group is named for the climatic Thornthwaite’s not moisture types required class, all the stations have that kind of soil or They modification. considered that the order zonally related soils in their neighbourhood; index of stations according to moisture was where more than one name is given the first satisfactory, except for a very few stations. The refers to more than half of the stations, and however, modifY moisture types, they wished to in most cases to more than two-thirds of the considerably. stations. To subdivide the moisture classes according to As the table shows, the climatic classes are for efficiency, were arranged part thermal stations then the most closely related to the main zonal in within the moisture classes order of the thermal soil groups. For some classes, however, the efficiency index (PE) from highest to lowest. The relationship is rather broad, indicating that Thornthwaite divisions into thermal efficiency the classification is capable of further refine- The pedologists types were shown. examined this ment. arrangement and were satisfied with most of the divisions, but they wished to modify Thorn- thwaite’s mesothermal ’1’ type. The upper limit ACKNOWLEDGMENT of mesothermal ’1’ was lowered, extending meso- Island low thermal ’2’ to cover North stations at Acknowledgment is made to the Meteorological Service for providing rainfall and temperature data and in particular to Mr J. Finkelstein who tl t tatio but the estimates dealt with and enquiries. onyse an the many requests 35 in (modified Thornthwaite, 1948) TABLE 2-7-2* Climate Stations of the New Zealand Sector Arranged Climatic Classes* after

Moisture Class (Range Humid Superhumid of Moisture Index Semi-arid Subhumid Subhumid to Humid (MI) in Thermal- paren- efficiency thesis) Class (Range ’A’ ’B’ ’A’ ’B’

of Annual Poten- --a (-30-0 (-5-0 20-6) (20-7 to 37*4) (37-5 to 66*8) (66-9 to 97-7) (97-8 to 215-0) (> 215-0) tial Evapotranspirat- to -5-0) to ion (PE) in parenthesis)

Megathermal (>44-9 in.) tNandi Airport tLaucala Bay Tropical

Mesothermal ’3’ (39-3 33-7 in.) TRaoul Island

- Subtropical

43 Hastings 46 Wanganui 32 Manutuke 10 Auckland 1 Te Paki 42 Napier 50 Tangimoana 31 Gisborne (Albert Park) 7 Riverhead 49 Ohakea 6 Dargaville 3 Kerikeri 12 Paerata 11 Oratia 21 Ruakura 4 Waipoua 15 Maramarua 5 Glenbervie Mesothermal ’2’ 22 Rukuhia 14 Whangamata (33 6 27 0 in.) 13 Thames 18 Waihi

- - - 24 Whakatane

Subtropical and mild 17 Paeroa 8 Woodhill temperate 16 Maioro 20 Tauranga 2 Kaitaia 25 Opotiki o 9 Whenuapai 19 Te Aroha

67 Westport Airp. 98 Alexandra 87 Timaru 102 Musselburgh 61 Nelson Airf’d. 106 Otautau 41 Karioi Downs Puysegur Pt. 97 Earnscleugh 88 Adair 73 Ashley Forest 57 Waingawa 108 Invercargill 65 Golden 107 Airf. 69 Greymouth 93 Cromwell 77 Wigram 51 Flock House 60Nelson(Cawth.) 34 Taupo 26 Rotorua 95 Ophir 91 Waimate 92 Queenstown 53 Palmerston N. 70 Hanmer 28 Waiotapu 71 Hokitika 96 Waipiata 63 Blenheim 66 Waihopai (Grasslands) 59 Kelburn 37 Taumarunui 83 Haast 27 Whakarewa- 90 Milford Sound Mesothermal ’1’ 89 Tara Hills 76 Christchurch tWaitangi, 81 Onawe, Akaroa 45 Gwavas (26 9 23 2 in.) 79 Lincoln Chatham Is. 56 Kapiti Island 58 Wallaceville rewa

- - - 38 N. Plym. Airf. 72 Balmoral 74 Lake Coleridge 44 Taihape 33 Waerenga-o- Palmerston N. 103 Tapanui kuri 39 New Plymouth Mild and cool temperate 64 Woodbourne 52 86 Fairlie (Boys’ H. S.) 101 Dunedin (Beta 54 Pahiatua 29 Kaingaroa 84 Ashburton 105 Gore St.) 23 Rotoehu 100 Taieri 62 Appleby, Nel. 55 Levin 35 Pukahunui 82 Winchmore 104 East Gore 78 ’Rudstone’, 30 Pureora 47 Waipukurau Methven 36 Onepoto, Lake 75 Darfield 48 Marton Waikaremoana

f Tucker Cove, 40 Chateau Microthermal ’2’ 99 Manorburn 85 Lake Tekapo Campbell Is. Tongariro (23 1 16 8 in.) Dam 94 Naseby - - - 68 Molesworth 80 Hermitage, Mount Cook Cool to cold high country and sub- antarctic

for is ’2’. ? PacUic Southern Ocean Stations Latitude Longitude *The climate class of Hastings station, example, subhumid mesothermal and increasing latitude; Nandi Airport, Fiji 170 45’S 1770 27’E New Zealand stations are numbered from the north in order of Laucala Bay, Suva, Fiji 180 09’S 1780 27t’E their locations are shown in Fig. 2-7-1- Raoul lsland, Kermadecs 290 15’S 1770 55’E Waitangi, Chatham Islands 430 57’S 1760 31’E Tucker Cove, Campbell Island 520 33’S 1690 09’E 2-7

TABLE 2-7-3* Classification of Climate Stations Not Included in Fig. 2-7-2-2-7-7.

Moisture PE for Water Water Station Height Index Year Deficiency Surplus Climatic Class (ft) (MI) (in.) (in.) (in.)

Semi-arid mesothermal ’1’ 97 Earnscleugh 500 1 24 8 11 -2 - - -27 . . 95 Ophir 1000 24-1 7-8 -19-4 ,, ,, ,, ,, 45 14 2 27 5 2 5.. 1 Subhumid mesothermal ’2’ 43 Hastings - - - -0 1-8 Subhumid mesothermal ’I’ 88 Adair 280 -4*4 24-8 71 0-5 25-8 3-6 2-3.. 77 Wigram ,, ,, ,, 79 Lincoln 36 6-9 25-2 2-1 3-0 ,, ,, ,, 29 7 27 0 8 0 Subhumid to humid ’A’ mesothermal ’2’ 8 - 50 Tangimoana - - .. 104 EastGore 245 37-4 24-6 9-2 Subhumidtohumid’A’mesothermal’l’ .. 10 Subhumid humid ’B’ mesothermal ’2’ 61 Nelson Airfield 6 38 6 25 9 -0 to - - . . ’2’ 150 70 2 27 9 19 6 Humid ’A’ mesothermal 12 Paerata - - - .. 22 Rukuhia 215 74 9 27 5 20* 6 - - ,, ,, ,, ,, . . 8 Woodhill 100 81-4 27-9 22-7 ,, ,, ,, ,, 12 85-5 27-6 .. 23-6 20 Tauranga ,, ,, ,, ,, .. 58 Wallaceville 215 95-4 26-0 24-8 Humid’A’mesothermal’l’ .. 135 127 5 27 3 34 8 Humid ’B’ mesothermal ’2’ Oratia - 11 - - . . 14 Whangamata 50 154-7 27*8 43-0 ,, ,, ., ,, 970 104 2 26 3 .. 27 4 Humid ’B’ mesothermal ’1’ 26 Rotorua Airfield - * - . . 28 Waiotapu 1250 108-0 25-0 27-0 ,, ,, ,, ,, Airfield 142 125 2 26 6 .. 33 3 38 New Plymouth - - - ,, ,, ,, ,, 1785 137-6 24-5 . . 33*7 29 Kaingaroa ,, ,, ,, ,, .. 2190 165 7 23 6 39 1 35 Pukahunui - - - ,, ,, ,, ,, .. 107 Puysegur Point 143 257-0 24-9 34-0 Superhumid mesothermal ’1’

..

1948 TABLE 2-7-4- Climatic Subdivisions According to Thornthwaite’s Classification of (after Thornthwaite, 1948, and Thornthwaite and Hare, 1955)

Therm cn Index Moisture Index (MI) Moisture Province Thermal Province

A perhumid > 44 9 A’ Megathermal 100 and above - 39-4-44-9 B’s 80 to 99-9 B, humid 33*7-39-3 B’" 60 to 79-9 B, humid Mesothermal B, humid 28 1-33 6 B’s g 40 to 59 -9 - - 22-5-28-0 B’s I 20 to 39-9 B2 humid . 16-9-22*4 C’s ( 0 to 19-9 C, moist subhumid Microthermal 11-3-16-8 C’s to 0 Cx dry subhumid J -19-9 5-7-11*2 D’ Tundra -39-9 to -20 D semi-arid E arid 0- 5-6 E’ Frost -60 to -40

Classes TABLE 2-7-5- Zonal Soil Groups Related to Climatic

No. of Climatic Class Zonal Soil Groups Characteristic of the Figure nds Climatic Classes Moisture Class Thermal-efficiency Class S

2-7-2 Semi-arid Mesothermal ’1’ 6 Brown-grey earths Microthermal ’2’ I Intergrades from BGE to YGE (high country) ,, Subhumid,, Mesothermal ’2’ 2 Yellow-grey earths (YGE) ,, Mesothermal ’1’ 15 Yellow-grey earths ,, ,, Microthermal ’2’ 3 High country yellow-brown earths (YBE); one ,, ,, (station) high country intergrade from YBE to YGE YGE; 2-7-3 Subhumidtobumid’A’ Mesothermal’2’ 3 Intergrades from YGE to YBE; some Mesothermal ’1’ 11 some YBE 2*7-4,, Subhumid,, ,, humid,, ’B’,, Mesothermal ’2 2 to Intergrades from YBE to YGE Mesothermal ’1 12 ,, ,, 2-7*5,, Humid,, ’A’ ,, Mesothermal ’2’ 16 Northern YBE; some central YBE 8 YBE 2 6 Humid ’B’ Mesothermal ’2’ Northern -7 - 2-7-5 Humid ’A’ Mesothermal ’1’ i 9 Central and southern YBE 2-7-6 Humid’B’ Mesothermal’1 13 CentralYBE peat Humid ’A’ Microthermal ’2’ 1 Blanket (subantarctic) YBE 2-7-7,, Superhumid Mesothermal’l’ 6 Gley podzols; some central and southern Microthermal ’2’ 2 Subalpine gley podzols ,, ,, 1 Not known Subhumid to humid ’A’ Megathermal ,, Humid ’B’ Megathermal 1 Not known ,, Humid ’A’ Mesothermal ’3’ 1 Not known ,, 2*7

I16oE 1680 1700 172o 174o I 1760 1780 E I 1 1 I I at- S _,40 NORTH ISLAND

I Te Paki 31 Gisborne I 2 Kaitaia 32 Manutuke 3 Kerikeri 33 Waerenga-o-kuri 42 4 Waipoua 34 Taupo 3 5 Glenbervie 35 Pukabunul 6 Dargaville 36 Onepoto 5 7 Riverhead 37 Taumuranui 4 8 Woodhill 38 New Plymouth Airfield 46 o 9 Whenuapai 39 New Plymouth Auckland(Albert Park) o 10 40 Chateau Tongariro - 36 I J Oratia 41 Karioi Paerata 12 42 Napier 7 Thames 13 43 Hastings 8 Oc-7 14 Whangamata 44 Taihape I Maramarua 13 15 45 Gwavas 12 14 16 Maioro 46 Wanganui 16 17 17 Paerva 47 Waipukurau 4 8 18 Waihi 48 Marton 21 19 Te Aroha Ohakes 49 22 20 Taurange 23* 80 50 Tangimoang 24 21 Ruakura 2 380 SI Flock House 26 27 - Rukubia 28 22 52 Palmerston North (B.H.S.) 30 23 Rotoehu 53 Palmerston North (Grassiands) 34 31 24 Whakatane 54 Pahiatua 33 37 2 25 Opotiki 55 Levin 3 36 . 38 26 Rotorua Airfield 56 Kapiti island 39 440 27 Whakarewarewa 57 Waingawa 28 Waiotapu 58 Wallaceville 41 29 Kaingaroa 59 Kelburn Wellington 40 30 Pureora 43 d. (47 47 50 51 52 -4 53 *54

5 457 458 62 60 61 64 5 654 63

6 66 468 420 SOUTH ISLAND

~ 60 Nelson(Cawthron) 85 thke Tekapo - 420 69 470 61 Nelson Airfield 86 Fairlie 62 Appleby 87 Timaru 71 724 63 Blenheim 88 Adair 64 Woodbourne 89 Tara Hills 73 65 74 Golden Downs 90 Milford Sound 4 66 Waihopai 91 Waimate 7 6 784 67 Westport Airport 92 Queenstown 0 79 44* +82 ] 68 Molesworth 93 Cromweli 83 g44 69 Greymouth 94 Naseby gg 4 70 Hanmer 95 Ophir 44o 4 86 - 87 71 Hokitika 96 Waipiata 440 89 88 72 Balmoral 97 Earnsdeugh 73 Ashiey 98 Alexandra 74 Lake Coleridge 99 Manorburn Dam 92 93 95 494 75 Darfield 100 Taieri 974498 494 76 Christchurch 101 Dunedin (Beta Street) 77 Wigram 102 Musselburgh 78 Rudstone, Methven 103 Tapanui 79 100410 Lincoin 104 East Gore 103 80 The Hermitage 105 102 Gore 106 81 Onawe. Akarea 106 Orautau 460 107 04:105 - go 82 Winchmore 107 Puysegur Point - 108 83 Haast 108 Invercargill 84 Ashburton

50 0 50 100 150 200

Scale of Miles

486 I I I I I - I 1 I 480 S - 166oE 1680 1700 . 172o 1740 176o 1780 E 180% Fla. 2 7 Location of meteorological - *1 - stations.

38 2-7

FIG. 2-7-2 2-7*7* Water balance according Thornthwaite’s classification (1948). - to

POTENTIAL EVAPO- WATER SURPLUS

TRANSPIRATION

e--e PRECIPITATION WATER DEFICIENCY

MI MOISTURE INDEX SOIL MOISTURE THERMAL A PE EFFICIENCY UTILISATION (POTENTIAL EVAPO- TRANS.FOR YEAR) SOIL MOISTURE - RECHARGE

SEMI-ARID,MESOTHERMAL "1"

98 ALEXANDRA 320th 93 CROMWELL nott 96 WAlPIATA issoft 89 TARA HILLS isoott

4.0 in. 1*6 $. n. 3*31n. ll*91n. 9-5in. 4*5La. 0 1 1.8 In. 1*0 1* ist MI MI 28*4 PE25-trin. MI-22*9 PE 2 91n MI-16*4 23*8in. -? 9 PE D*Sin t I (PE JFMAMJJASONDJ JFMAMJJASONDJ JFMAMJJASONDJ JFMAMJJASONDJ

SEMI-ARID, MICRO. "2" SUBHUMID, MESO. "2"

42 NAPIER sft 99 MANORBURN DAM 24481 o

4-0 0.

5-21n. 1-5f 2*

4*0 in. 2*s in.

E 21p21n, re a JFMAM ASONDJ 49 ANJ ASONDA

SUBHUMID, MESOTHERMAL "P

87 TIMARU 561 91 AIMATE2oore 63 BLENHElit 14ti 76 CHRISTCHURCH22tt 4 4*01n 3 in 4*01n. 4*Din t ,3-61n. 3*D1n. 4.01n.

9 in.3*I 4*0 in in.

*3 In. £*8

Z MI-4*3 PE 25*4 in. MI 1-2 PE 25-5In- MI 2*4 PE 26*61n. MI 6*2 PE 25.91n.

JFMAMJJASONDJ AFMAMJJASONDJ JFMAMJJASONDJ JFMAMJJASONpl

O 64 WOODBOURNE 90ft 86 FAIRLIE IDO4It 84 ASHBURTON 323ft

M 8*3 PE24 9in. Mil 10*31 26-71n. M fl*6 4* In MI 12*0 I I I II I IPE 1 1 1 ill IPEl isIa rrP 1251*51n. FMAM JASONDJ J FMAMJ JASONDA F MAMJ JASONDJ J FMAMJJ ASONDJ

100TAIERisoft 81WINCHMORES26tt 47WA1PUKURAU4soft 75DARFIELD 640th

4*0in- 5-5In 5-3ln.

4*2 In. 49n. n.

3-2 in

fil 20-9 PE 25*31n. 13 PE 2 Mr PE 6 lip. .9 -Sin MI 9-7 eleast IPE,2 I ite JFMAMAJASONDJ JFMAMJJASONDJ JFMAMJAASONDJ JFMAMJJASONDJ

SUBHUMID, MICROTHERMAL "2"

85 LAKE TEKAPO 2240ft 94 NASEBY 2Dooth 68 MOLESWORTH 2930tt

2-3 in. 4-0 in. p 2.2 in. 4*0 in.,

in. iii= *0 in. 4-0 in.l*4 1-5 In. *0 in.

In. 3*0 In *5

MI 0*1 PE 23-1In. MI 6*5 PE 22*91n. MI 9-7 PE 22-51n

JFMAMJJASONDJ JFMAMJJASONDJ JFMAMJJASONDJ

FIG. 2*7-2

39 2*7

SUBHUMID TO HUMID "A". MESO."2"

46 WANGANUI 72ft 49 OHAKEAlssft 4

MI 25*6 PE 27*4in- MI 31*4 PE27*Iin. f itittlif lilif titlfilfilif J FMAMJ JASONDJ J FMAMJ JASONDJ

SUBHUMID TO HUMID "A’ MESOTHERMAL "1"

102 MUSSELBURGH 73ASHLEY FOREST ason 51 FLOCK HOUSE30ft 92QUEENSTOWNresort 5ft 4 4 2-7in 7-lin. 5*71n: 6-41n

3-3in.

3-3in.

PE 26-4in. Ml 29-0 PE 24-8in. MI 22*5 PE 25-3in. MI 254 PE 25*4in. MI 26-9 1 Ti I I I 1 I 1 I I I 4 ! I T I I ft I ( 1 f f IT f f I I F I I I I 1 1 1 1 1 1 I 1 I I 1 I 1 I 1 1 JFMAMJ JASONDA J FMAMJ JASONDJ J FMA-MJ JASONDJ J FMAMJ JASONDJ

66 WAIHOPAI ason CHATHAM 15LANDSloort O 4 7*61n k8*2jn.

in.

3*9 in

MI 29-1 PE 26-0in MI 32-7 PE 25*Iin.

J FMAMS JASONDJ J FMAMJ JASONDJ

51PALMERSTON NTH icoft 74 LAKE COLERIDGEII95ft 105 GORE 230 ft 62 APPLEBY, NELSON 57(t 5 ------(B.H.S.)

1

PE 24*8in MI 37-2 PE 26-8in. MI 33*I PE 24-8in MI 35*4 PE 26-8in MI 35-1 IIritil Still lifillI (Illltillllit littirillilli JFMAMJJASONDJ JFMAMJAASONDS JFMAMAJASONDJ JFMAMJJASONDJ FIG. 2-7*3

40 2*7

SUBHUMID TO HUMID "8". MESOTHERMAL "2"

32 MANUTUKE toop 31 GISBORNE 14 A

Mil 37 PE 27 6in MI 43 7 PE 277in.

I r I I I I J FMAMJ JASONDJ JFMAMJ JASONDJ

SUBHUMID TO HUMID "B". MESOTHERMAL "1"

57 WAINGAWA 60NELSON(CAWTHRON) 34oft 34f 53 PALMERSTON NTH troft 81 ONAWE. AKAROA isort (GRASSLANDS) p 5

I 8 in,

in.

n I MI 45 0 PE 26 2 in. MI 54 5 PE 26 Bin M 46 PE 26 En MI 47 7 PE 26 6 in Z- if ( ill II II Ill illlll 1 lilli II (1 I I[ il ( 1 fl 1 I II ( IllI 4 Z JFMAM13ASOND) JFMAMJJASONDJ JFMAMJJASONDJ JFMAMJiASONDJ

12g 12h 12e 12f

103 TAPANUI 74orr 101 DUNEDIN (BETA ST)7oop O 56 KAPITI ISLAND 4th 44 TAIHAPE 2/370 Z4

? 15 MI 47 8 PE 26 8 in. MI 8 PE PE 24 3in. MI 52-2 PE Sin. 49 24 Sin. MI 49 8 2 Ilillillliill IIIllillIlli) 1(ifillillll! JFMAMJJASONDJ JFMAMJJASONDJ JFMAMJJASONDJ JFMAMJJASONDJ

IZi 12) 12k

55 LEVIN loop 78 "RUDSTONE METH N 48 MARTON 462ft 217ft

0 2 in 0 2 0 7 an

16 7 in. 16 3 in. 7 -I in

MI 63 3 PE 26 4in MI 64 9 PE 25 lin MI 66 8 PE 25 6 in. Iflililifilli Illil IIllill lilifilrilill

JFMAMJ JASONDJ J FMAMI JASONDJ J FMAMJ JASONDJ FIG. 2-7*4

41 2*7

HUMID "A", MESOTHERMAL "2"

6 - 10 AUCKLAND 160ft- - 6 DARGAVILLE 64ft- --- 21 RUAKURA Dire - 15 MARAMARUA 124{<- 6 3 A RTitt r 5 19-9 19-9 in. 19-8 in. in. 20-3 In.

0*8 in. l*l in. 1-1 in.

MI 68*6 PE 29*0in Mr 70-2 PE 28 2in. MI 73*4 PE 27-1 in, MI 73.5 PE 27-6in Illiflifillli flill?llfilif lilli Illilli lirtliliffIII 5 FMAMS JASONg) J FMAMJ JASONDJ 3 FMAMS JAEONDA J FMAMJ JASONDJ

13 THAMES fort 24 WHAKATANE 6ft- 17-PAEROA 27ft 16 MAlORO 172ft - - - 6 6 22-7in- 22-7 in 5 2t*6in, 0-7in. 21-8in,

in; Plio. 1-lin. 0-Ain. ,0

I 28*4 MI 77 I PE 28*0 MI 77-6 PE 28-lin MI 79.9 PE in. Illiffilllill 111111111111) jjittillijill I 111111111 JFMAMJJASONDS JF.MAMJJA’SONDA JFM.AMJJASONDJ AfMAMJJASOND

2 KAITAIA 26tre 25 OPOTIKI 2ort 9 WHENUAPAt tout 19 TE AROHA 40ft 7 7

26 -4 in. 27*9 in. 26-1 ID* 0 0

MI 87*5 PE 28-ain MI PE 27*2in. MI 96*0 MI 96*3 PE 27*4in. 97 2 O 1111111111111 1111111)?1111 1111111971111 I JFMAMAJASONDJ JFMAMJAASONDS JFMAMJ3ASONDJ JFMAM11ASOND

HUMID "A", MESOTHEI\MAL "1"

70 HANMER 1270ft 106 OTAUTAU tooft 108 INVERCARGILL 33ft 34 TAUPO 122/ft 6

5 l-3in / 206in , .

PE 24 ?in Mt 70-0 PE 24*3in MI 73-7 24-7in. MI 82*3 PE25-8in. MI 83 4 I I 1 1 IP JFMAM JASOND) JFMAMJJASONDJ JFMAM)JASOND) JFMAM ASONDA

54 PAH ATUA ssoft- 7 59 KELBURN 41s ft- 45 GWAVAS t rooft- 33 WAERENGA-O-KURI Jo30ft - - -

25-7 in. 5

22.5

. 0-9in.

r PEll6 31n. MI Wj MI 87-5 PE 25-7 in. MI 96 2 PrE 26-lin MI 97*7 r II I st 126-3in: JFMAMJJASONDS JFMAMJJASONDJ JFMAMJJASONDJ }FMAMJJASONDJ

FIG. 2*7-5

42 2*7

HUMID "B", MESOTHERMAL"2"

10 3 KERIKERI 240 ft I TE PAKI $90[< 7 RIVERHEAD los-ft 9

0

35-3 in. 2’’"" 2a-2 in. 5 lil

III - - U

MI 124 3 PE 28-4 in. MI 98-6 PE 28*6 in. MI 107-0 PE 27-3 in.

JFMAM JASONDJ JFMAMJJASONDJ JFMAMJJASONDJ

10 4 WAIPOUA 2zsft 5 GLENBERVIE3sore 18 WAIHI 300[:

8

5B*S in. 7

37*5 in. 41-5 in. 6

O MI 136*9 PE 27-4in. MI 152*0 PE 27*3in. MI 213*5 PE27*4in, till!Filillit Illilllifilel III IFlillill a JEMAMJJASONDJ JFMAMJSASONDJ JFMAMJJASONDJ HUMID "B", MESOTHERMAL "1"

7 O 41 KARIOI 2I2ste 65 GOLDEN DOWNS9oort 37 TAUMARUNUI 362ft 27 WHAKAREWAREWA Z 6

Mi 4 U M IO2-3 Mi llO*I PE 26-7in. Mi ll8-71 l00 8 n. PE 4 in. 26-lin. 1 Il i l l IPE . )24 Il l i t IPE JFMAMJJASONDJ JFMAMJJASONDJ JFMAMJJASONDJ JFMAMJJASONDJ

39 NEW PLYMOUTH 16ort 23 ROTOEHU 23srt 30 PUREORA looort 36 ONEPOTO 2nort

, I

11

127 Sr PE 26*Tan M 207-6 25-01n. MI MI 43 8 MI MI 2 PE 24 O n. if if II 126*91n.

JFMAMJJASOND) JFMAMJJASONDS JFMAMJJASONDJ JFMAMIJASONDJ HUMID"B", MICROTHERMAL "2"

TUCKER COVE, CAMPBELL ISLAND 6

2

34-7 in.

H I 9 PE 22*4 in.

JFMAMJJASONDJ

Flo. 2-7*6

43 2*7

SUPERHUMID, MESOTHERMAL "1"

90 MILFORD 16ft 67 WESTPORT 6# 69 GREYMOUTH II 71 HOKITIKA 120 83 HAAST 12ft 2( 2E 24 - - - - Its*Cin. 23- 22- .22e*9in.

83.7 i 10 20 - , 71-2in L I 9 19 59-3 in. Z 8 8 -

E 2518 n I I IP J FMAMJ A ASONDJ J FMAMJ JASONDJ J FMAM) JASONDJ J FMAMJ J ASONDJ - 9 SUPERHUMID, MICROTHERMAL "2" 8 40 CHATEAU 3670 80 HERMITAGE,2sooft 7 - TONGARIRO MT.COOK 6-

19 5 / . - 18 4 - 17 3

16 2 149.8 n --- 1 5 l 31 E in) i I 1 J FMAMJJASONDJ

o 12 92 in.

6

2

Mt4220 P il8n I6M PE229n)

J FMAMJ J ASONDJ J FMAMJ JASONDJ SUBHUMID TO HUMID HUMID "B" HUMID "A",. "A,, ’ MEGATHERMAL MESOTHERMAL"3" KEY MEGATHERMAL

NANDI AIRPORT 49ft LAUCALA BAY, SUVAleft RAOUL ISLAND 126ft M POTENTIAL EVAPO- TRANSPIRATION 11

- PRECIPITATION 13

12 MI MOISTURE INDEX 64-a in

PE THERMAL EFFICIENCY 20-6in. (POTENTIAL EVAPO- 9 - - - TRANSPIRATION FOR 8 - YEAR) 4-o in. 7 WATER SURPLUS - - - 24-9 in. -6- - - -

ggy wATER DEFICIENCY .4 in.

0*21n

MOISTURE 4-oin SOIL 2 UTILISATION

MI38-8 PE52-5in. MI122-3 PE53*0in. MI 72*4 PE 34*4in,

istilititler ricti litists irrrIIIIIllir SOILMOISTURE 1FMAMJAASONDJ JFMAMJJASONDJ JFMAMJJASONDJ RECHARGE

FIG. 2*7-7

44 2-8

2-8- PROVISIONAL CLASSIFICATION OF SOL CLAYS

FOR USE IN PHASING SORS*

by M. FIELDES

The clays commonly found in parent materials soils, for example, may be illo-fulvic, vermo- and other horizons are classified provisionally fulvic, moro-fulvic, kao-fulvic, etc. Suitable adjec- below. tives can be added as required to show subordinate For special investigations the phases of fulvic clay constituents.

Prefix Prefix Classification of Clays (for Dominant Classification of Clays (for Dominant Constituents) Constituents)

1. Amorphous hydrous colloids 3. Crystalline oxides and hydrous oxides Allophane (Si-Al; ex rhyolitic or (a) Of silicon andesitic glass) Allo- Hydrous feldspars tazrtz Silico- (Si-Al; ex S feldspar) Hydrofelso- ArT Hydrous alumina (Al; ex basic (b) Of aluminium and ultrabasic minerals) Hydroalumo- Gibbsite Gibbso- Palagonite (Si-Al; ex basalt or (c) Of iron basaltic glass) Palago- Goethite Lepidocrocite 2. (Crystalline) Layer silicates Ferro- (a) Micaceous Magnetite Weakly Mico- hydrated mica (d) Of Illite Illo- titanium Anatase Titano- Clay-vermiculites Vermo- Montmorillonite Moro- (b) Kaolinic Metahalloysite 1 K ao- Kaolinite J *Modified after Fieldes (1958).

2-9- REFERENCES

AUBERT, G.; DUCHAUFOUR, PH. 1956: Projet de Classifica- HEALY, J.; VUCETICH, C. G.; PULLAR, W. A. 1964: Strati- tion des Sols. Trans. 6th int. Congr. Soil Sci. (Comm. V) graphy and Chronology of Late Quaternary Volcanic E: 597-604. Ash in Taupo, Rotorua, and Gisborne Districts. N.Z. geol. Sury. Bull. n.s. 73. 88 pp. BORNEBUSCH, C. H.; HEIBERG, S. O. 1936: Proposal to the Third International Congress of Soil Science, Oxford, HURST, F. B. 1951: Climates Prevailing in the Yellow-grey England, 1935, for the Nomenclature of Forest Humus Earth and Yellow-brown Earth Zones in New Zealand. Layers. Trans. 3rd int. Congr. Soil Sci. 3: 259-60. Soil Sci. 72: 1-19.

CLARKE, F. W. 1924: The Data of Geochemistry. U.S. geol. JENNY, H. 1941: ’Factors of Soil Formation’. 3rd ed. Sury. Bull. 770. 841 pp. McGraw Hill, New York. 281 pp.

CLARIDGE, G. G. C. 1965: The Clay Mineralogy and Chem- JOFFE, J. S. 1949: ’Pedology’. 2nd ed. Somerset Press, N.J. istry of Some Soils from the Ross Dependency, Antarctica. 662 pp. N.Z. J. Geol. Geophys. 8: 186-220. KANNO, I. 1957: A Scheme for Soil Classification of Paddy DRUCE, A. P. 1966: Tree-ring Dating of Recent Volcanic Fields in Japan with Special Reference to Mineral Paddy Ash and Lapilli, Mt. Egmont. N.Z. J. Bot. 4: 3-41. Soils. Soil and Pl. Food: 148-57. (Also in Bull. Kyushu Exp. Sta. 4(2): 261-73. 1956.) FIELDEs, M. 1958: Soil Science and Extension Work. The agric. Role of Clays in Soil Fertility. Proc. N.Z. Inst. agric. Sci. KRUSEKOPF, H. H. 1942: ’Life and Work of C. F. Marbut: [4]: 84-101. A Memorial Volume’. Soil Science Society of America. pp. FINK, J. 1956: Zur Systematik fossiler und rezenter Liss- 271 b6den in Osterreich. Trans. 6th int. Congr. Soil Sci. McLINTOCK, A. H. (Editor) 1959: ’A Descriptive Atlas of (Comm. V) E: 585-96. New Zealand’. Govt. Printer, Wellington. 109 pp.

FRIDLAND, V. M. 1958: [Podzolisation and Illimerisation.] McCRAw, J. D. 1959: Periglacial and Allied Phenomena Pocvovedenie 1958 (1): 27-38. (In Russian.) in Western Otago. N.Z. Geogr. 15: 61-8. GARNIER, B. J. 1951. Thornthwaite’s New System Climate of NIKIFOROFF, C. C. 1959: Reappraisal of the Soil. Science Classification in its Application to New Zealand. Trans. 129: 186-96 roy. Soc. N.Z. 79: 87-103. N. Soil Map of New Zealand. N.Z. GERASIMov, I. P. 1960: Gleying Pseudo-podzols of Central Map 01948: Europe and the Formation of Binary Surface Deposits. ilS7uLr.BUREA . Cycle Weathering’. Thomas Soils and Fert. 23: 1-7. PotYNov, B. B. 1937: ’The of Murby, London. 220 pp. GRADWELL, M. W. 1957: Patterned Ground at a High Country Station. N.Z. J. Sci. Tech. B38: 793-806. RAESIDE, J. D.; CAMERON, M.; MILLER, R. B. 1959: Soils 1960: Soil Frost Action in Snow-tussock Grassland. and Agriculture of Part Geraldine County, New Zealand.

-- N.Z. J. Sci. 3: 580-90. N.Z. Soil Bur. Bull. 13. 65 pp.

45 2*9

TAYLOR, N. H. 1949: Soil Survey and Qassification in New U.S. Son SURVEY STAFF 1951: Soil Survey Manual. Handb. Zealand. Proc. 7th Pacif. Sci. Congr. 6: 103-13. . U.S. Dep. Agric. 18. 503 pp. . 1955: The Role of Soil Science in New Zealand 1960: for Utilising Solar - VINCZE, S. A. New Scope Energy. Problems. Trans. roy. Soc. N.Z. 82: 961-72. Engineering: 824-5 1956: Soil Science in the U.S.S.R. Proc. N.Z. Soc. - der Soil Sci. 2: 12-16. VoN KuNGE, A. 1956: Zur Frage zeitlichen Einordnung rezenter und vorzeitlicher Kalksteinbaden der iberischen TAYLOR, N. H.; Pom.EN,.I. J. 1962: Soil Survey Method. Halbinsel (mit Farbdisposition). Trans. 6th int. Congr. N.Z. Soil Bur. Bull. 25. 242 pp. Soil Sci. (Comm. V) E: 31-5. THORNTEVArrE, C. W. 1948; An Approach . towards a Zorov, V. D. 1938: Survey of Tussock-grasslands of Rational Classification Clunate. Geogr. 55-94. the the of Rev. 38: South Island, New Zealand. N.Z. J. Sci. Tech. A20: THORNTHWATTE, C. W.; HARE, F. K. 1955: Climatic Classi- 212-44. (Also issued as N.Z Dep. sci. industr. Res. Bull. fication in Forestry. Unasylva 9: 51-9. 73. 1938.)

46 CHAPTER 3. REGIONAL DESCRIPTION OF NEW ZEALAND SOILS

3-1- GENERAL INTRODUCTION

by H. S. Glass

New Zealand has a wide array of soils owing classes the following convention has been adopted. principally to the many kinds of parent rocks and (a) The zonal grade of weathering of soils is the varied conditions for their transformation assumed unless otherwise stated. into soil (see Chapter 1). These soils have been (b) The classified by the methods described in Chapter 2 zonal names are omitted where soil classes occur only in one and the zonal arrangement using common names the zone, e.g. brown-grey yellow-brown pum- has been adopted for presentation of the detailed earths, and ice data in this and subsequent chapters of the bulletin. soils. Technical names giving precise definition of the A more detailed pattern of soil units is shown representative soils are set out with the alternative on the soil maps of North and South Islands on common names in descriptions of soil types the a scale of 1:1,000,000, contained in the pocket at in Chapter 11. the back of the bulletin. These maps have been The overall pattern of soil groups and sub- compiled from general soil maps of both islands groups is shown on Figs. 3 1 1 and 3 1 2. * * - - on a scale of 1:253,440 (4 miles to I inch) and are Regional names are applied zones as fol- to the the link between them and the soil-group maps lows: (Figs. 3-1*1 and 3-1-2). The units are for the High country for the elevated inland region of most part associations of series, but some are the South Island where the rate of mineral groupings of series that do not occur together weathering (argillisation) is slow and broadly geographically. Associations and groupings are classed as weak. made at the approximate level of the soil family, but family have been Southern for the coastal lowlands of the South soil names not allotted on present knowledge. Associations Island south of Rangiora on the east coast and the state of our are named according leading series, of Ross on the west coast. In this zone the rate to the the being joined hyphen. Normally of mineral weathering is moderate to slow and names with a the given broadly classed as submoderate. dominant soil is first, but for a few associa- tions the subdominant is given priority where it Central for the coastal lowlands of the South is an important soil and where, by emphasising Island north of Rangiora and of Ross and for it, the intergrades are better expressed. Groupings the North Island as far north as and including, of series that are not geographically associated the Waikato and Bay of Plenty districts. In are named, as are the associations according to this zone the rate of mineral weathering is dominant and subdominant series within moderate and is broadly classed as moderate them, names being joined by ’and , The various but increasing the towards the northern end. . headings and subheadings in the legend on the Northern for North Auckland, Auckland, the soil maps are based primarily on the classification and Coromandel districts where rates of the of the leading soils of the mapping units. The broadly mineral weathering are rapid and descriptions are necessarily brief and no mention classed as strong- is made of the less important members of the This zonal designation does not imply that all the associations. More complete descriptions are given soils in that zone are equally weathered. The factors in the representative set of soil survey reports of time or topography can reduce or increase the listed at the end of this chapter. grade of argillisation of particular soils (Chapter The soils are described according to the regions 2 3). To avoid unnecessary words in naming soil shown in Fig. 3 1 3. - the - -

47 3*2

3-2* SORS OF NORTH ISLAND

by H. S. Gmas, J. D. Cows, and W. A. PULLAR

TAUPO BAY OF PLENTY class; similar effects on soil are produced on - the (Region A, Fig. 3-1-3) outer edges of deposits from paroxysmal eruptions,

. important difference being rate and The Taupo Bay of Plenty region begins in the the thick- - ness of the accumulation. Age and composition the centre of the North Island as high undulating of deposits, local climate, vegetation, and plateaus surrounding isolated volcanic peaks and the are also important kind of soil separated by lava bluffs, river gorges, and numer- topography to the formed. ous lakes. The plateaus slope generally downward Four groups described: towards the north and without distinct barrier of soils are into the Bay of Plenty. On the east of the region 1. Central recent soils from volcanic ash erupted ft mountain ranges form a long strip 3,500 to 5,500 in historic times, high; to south and west the region is bounded by 2. Yellow-brown pumice soils from materials deeply dissected steeplands of other regions. The erupted approximately between 500 and 5,000 highest parts are in Tongariro National Park, years ago, which includes Mounts Ruapehu (9,175 ft), Ngau- 3. Central yellow-brown loams from materials ft), (6,517 ft). Upper ruhoe (7,515 and Tongariro erupted more than 5,000 years ago, but prob- regions drain into Lake Taupo, which supplies ably less than 50,000 years, the Waikato River with a large and steady stream 4. Steepland soils associated with each of the for generation hydro-electric power of water of above three groups. along its course South Auckland lowlands. to the The age ranges given for the different soil Annual average 60 in, 80 in., with rainfalls to groups are estimates for materials from paroxysmal 100 in, and more near mountains and only the eruptions (based on "C datings of buried vegeta- 50 in. near the coast. Most of the area has been tion) and give an indication of the length of time covered in forests, but large tracts were deforested that the materials have been exposed to weathering. during eruptions and had or shrub cover tussock Some soils included in the yellow-brown loams at of Maori settlement. Large plantations of time have shallow surface deposits of materials erupted exotic have been established and are being trees less than 5,000 years ago. used for timber and paper production. 1. Central recent soils from volcanic ash comprise The soil pattern of the region is dominated by Ngauruhoe (97a), Rotomahana (96a), and the distribution of materials from numerous the Tarawera (96b) soils. volcanic eruptions during the last 20,000 years (Fig.1-2-1).Lava,pumice,sand,andashhave Ngauruhoe soils are derived from andesitic been erupted many times from vents along the sand intermittently erupted from Mounts Ngauru- years. crustal fracture of the Taupo volcanic zone across hoe and Ruapehu over the last 400 Deposits 3 in, in the region from Tongariro National Park north- more than thick occur an oval area around (see in pocket, eastward to White Island. Road cuttings leading the two mountains soil map and profile description out of the region reveal a series of ash beds totalling Fig. 1-2-1). A of a representative given in 10 ft or more in thickness and increasing in depth site for Ngauruhoe sand is Chapter 11. and number towards the eruptive centres, par- This is a deep friable soil with high carbon in the gradual burial ticularly near Taupo and Rotorua. Most of the subsoil from the of successive indis- eruptions have been of the paroxysmal type in topsoils. For the same reason horizons are which a large volume of material was ejected over tinct. Under cool wet conditions mineral weather- a short period, completely burying the previous ing is slow, as is also the decomposition of organic soil and vegetation. Soil formation and plant matter and accumulation of nitrogen (Chapter 11). growth began again on raw mineral materials. Vegetation is red tussock. This land is not being Deposits of Tarawera and Taupo eruptions are farmed at present although extensive sheep grazing been in past. Deep deposits liable of this class. Less commonly eruptions have was tried the are to bare loose of the intermittent class in which small amounts wind erosion and a considerable area of of materials are ejected on numerous occasions sand has been eroded near the saddle on the over long periods. The original vegetation and Desert Road. Deposits less than 3 in, thick occur soils have thus been gradually buried and their in a wide zone outside the oval area marked on growth and development interrupted continually the soil map. For example, deposits from eruptions by fresh materials. The historic eruptions of in 1945 were recorded as far east as Napier and Mounts Ruapehu and Ngauruhoe are of this as far south as Wellington. These deposits con-

48 168 E [70 172 174

Brown-grey earths

yellow per Southern earths 4

grey CO Central sellow earth .___ __ 4

High yellow countra brown earth CO Southern 55 iellow-brown earths._ _ __ cenual secombrown canne _- co

positab gley pod;ob Southern and

central pod,ols gicy parol and

-42 5 Southern tellow-blown santh ____ CS

Southernlellow-brownloany,______CS C ______C ,

Southern brown granular days_ ) ____ re non / IIanmer ’ cm

souarern gicy , recent and organ c soils

central grey ss recent. and organic ois_

5, bare CO Alpine rock, scree and ice 5 54 Shallow group and stony oil related to

oup ,

so ss Christchurch

s2

52 3 / 56 52

14 ------ri ---44

amaru

1

SS ’ 54 SOUTH ISLAND

,, ,

$4

47 MILES < ore 20 0 20 40 60 80 100 p 1 it ,

in e ir all

55

56

O

50

J.K DIXON 55

Compiled by HSGibbs from . soil surveys 174 168 E )70 by officers of the Soil Bureau. D.51.R.

FIG. 3 1-2- Zonal Soil Map of the South Island, New Zealand. 174 E 176*

N9 N5 yellow-grey Central earths

Central yellow-brown earths bl5 ,

yellow-brown Northern earths. N6

Northern podzolised yellow-brown podzols earths and

/ Centralyelow-brownsands. Kerik ti

N yellow-brown Northern sands N4 a NSp N5 pumice Yellow-brown soils N6

yellow-brown loarns granu Central and brown ar oams--

N5 granu Northern red and brown loarns and brown ar c ays / N9

\ ’s gley Central recent, and organic soils N4 -- 36 5 3 6 5 NO N5 N9 gley Northern recent, and organic soils--

Recent soils from volcanic ash - N4 N4 Alpine bare rock. scree and ice C

Shallow groups and stony soils related to Ns

NA Steepland intergrades group / soils and included w th re aled zona Auc N CO N4

NB

N5 CO

N9 CS Cd C4 auranga CB

o

,* a CO, C4 v 000 a - - C6 oo 3 8 0 og 0 opOo go 7 c4 00 o 0 a oo o od’ oo@ oo,o OO C4 coonooso aocooao@0ononoo oo oo no oce " & o a D co 0 0 p, 0 a opo - C Q a on

CS

4

apier

40

C6 NORTH ISLAND C4 C4 asser on MILES CO 20 0 20 40 60 80 100 lK.DIXON - ,4

Compiled by H.S. Gibbs from soil surveys Wellington

by officers of the Soil Bureau, D.S.LR 174 E 16

FIG. 3-1-1- Zonal Soil Map of the North Island, New Zealand. 3-2

m I I In 900 1740 178’W "

F

REGIONS 4

A TAUPO-8AY OF PLENTY B TARANAKI -WANGANUI E / C MANAWATU-WELLINGTON

0 36 D WAIRARAPA-GISBORNE //

E SOUTH AUCKLAND / A / F NORTH AUCKLAND D G NORTH-EASTERN SOUTH ISLAND //

H WESTERN / B 1 CENTRAL .

J EASTERN

K SOUTHERN " " C /

/D

G

H

,G

Imo 940 1 8ow

FIG. 3 1 3 Regions for descriptions of soils, New Zealand. - - -

49

D 3*2 tribute mineral elements to soils and their import- from vents in or about Lake Taupo and covered ance is illustrated by the absence of cobalt deficien- all of the Central Volcanic Region as well as parts cy from soils derived principally from Taupo of adjoining districts. Some areas were subse- ashes outside the mapped area of Ngauruhoe soils. quently covered by Kaharoa, Tarawera, Ngauru- Rotomahana soils are developed from the hoe, and Rotomahana ashes. It has been estimated rhyolitic sand, silt, and gravels violently ejected that approximately 5 cubic miles of materials were pro- from Lake Rotomahana in June 1886. They occupy ejected in the 131 A.D. eruptions. As eruptions 50 square miles of rolling and hilly land between gressed the proportion of coarse material decreased, Lake Rotorua and Mt Tarawera and traces are and over most of the area the soil-forming deposits found in soils 10 to 15 miles beyond the mapped consist of silty ash over sandy ash over gravelly boundaries (as far as Te Puke). A detailed profile sand or gravel. Around Lake Taupo the deposits developed on a deposit 29 in, thick, given in are very thick and the surface layer is a sand; in Chapter 11, demonstrates the limited extent to Gisborne district the gravelly sand extends beyond which organic matter has been incorporated and the silty and sandy ashes and forms coarse sandy structure has developed in 75 years. Below 3 in, surface soils. Both Taupo and Kaharoa ashes there is no apparent change. However, it is much consist largely of pumiceous rhyolite, banded richer soil than Ngauruhoe sand, owing mainly to rhyolite, and obsidian with a little feldspar, hydrothermal weathering of minerals before erup- hypersthene, and magnetite. The rhyolite of the tion but in part to greater rate of decomposition Kaharoa ashes is harder, less vesicular, and of organic matter under the warmer climate. whiter than that of Taupo ashes. These materials Where deposits are 6 to 15 in, thick, sandy loams have been converted by the action of climate and grouped have developed and have been cultivated and organisms into soils that may be in parent sown to grassland for dairy farming. By using sequences or suites named after the ashes. phosphates excellent pastures have been estab- The Kaharoa suite is well shown along a traverse lished and maintained. inland from Te Puke. Near Te Puke under an Tarawera soils are gravelly sands and gravels annual rainfall of 50 in, are the Paengaroa- derived from materials erupted from Mt Tara- Ohinepanea soils (56a) with 6 to 7 in. of black wera in June 1886. Deposits are approximately granular sand on brown loose sand. About 5 24 in, thick on the lower slopes of Mt Tarawera miles inland from the coastal highway the soil is and decrease rapidly to north and south but Oropi sand (56b), having a very dark brown top- slowly eastward to cover about 350 square miles soil with a more nutty than granular structure, of hilly and rolling lands to depths greater than and the subsoils reddish brown loose sands; 3 in. Dust from the eruption was collected in annual rainfall is about 60 in. Ten miles further Gisborne 50 miles to the east. Profiles show 1 in, inland under an annual rainfall of 80 in, and a dark greyish brown gravelly sand over greyish lower average temperature the very dark brown brown and black gravel and sand. The coarse topsoil is only 3 in. deep and overlies 2 to 4 in. particles are scoriaceous and include glassy basalt of very pale brown loose sand. Below 6 in, there showing few external signs of weathering; soil is a distinct boundary to dark reddish brown nutrients are derived principally from the small slightly compact sand that grades down into amounts of rhyolitic dust and Rotomahana ash reddish brown and brownish yellow sand. This is pumice erupted at the same time. Drainage and decompo- a weakly podzolised yellow-brown soil sition of organic matter are rapid and the combined mapped as Kaharoa sand (56b) and is the end effects of low moisture and nutrients make pastures member of the suite. difficult to maintain. The Tarawera soils are suited Soils derived from Taupo ashes, like those from to growing exotic trees that can root deeply and Kaharoa ashes, can be arranged in sequences of obtain benefit from old soils buried below Tara- profile development that are correlated with wera lapilli. differences of climate and vegetation. The profile of Taupo sandy silt (57b) described in Chapter 11 2. Yellow-brown pumice soils represents the member formed under forest (but Yellow-brown pumice soils are derived from in fern and manuka for about 200 years) and a rhyolitic materials (Kaharoa and Taupo ashes) of moderate rainfall (50 in.). It shows A and B huge paroxysmal eruptions. Kaharoa ashes were colour horizons and moderately developed aggre- Tarawera in gates in A horizon, erupted about 1,300 A.D. from Mt the which contains much two series of showers in opposite directions-one humus with low C/N ratio. With increasing rainfall set towards the north-west reached Tauranga and up to 60 in, and change to a mixed broadleaved- podocarp grade the other set towards the south-east reached forest, Taupo soils into Ngaroma profile Wairoa. Taupo ashes were erupted about 131 A.D. soils (57d), a of which is:

50 3-2

O I in. litter of leaves and twigs, stages of pasture establishment on yellow-brown 4 brown friable sandy silt with a moderately Ax m. very pumice soils and the subsequent need for frequent developed fine granular structure, potash. Cobalt is low in yellow- Bx 5 in. reddish brown loose silty sand with a fine application of brown pumice soils and small quantities must be firm pumice B, 9 in. low sand, prevent bush (Chapter 8). firm gravelly pumice added to sickness C on yellow to paleruj yellow sand. Increase in growth rates and total weight of sheep have been obtained by giving This soil has a slightly more fertile topsoil than and cattle recently doses Deficiencies Taupo sandy silt but has a poorer subsoil owing small of selenium. of other are likely arise under intensive to greater leaching. trace elements to because basic Under higher rainfall (80 in.) and a mor-forming farming of these soils contents of bulk forest (rimu-kamahi), Mamaku sandy silt (57f) is minerals are low and because the of the soil particles limited developed on Taupo and older rhyolitic ashes. A material consists of coarse with plant profile is: area exposed to weathering and roots. Hence nutrient demands of rapidly growing plants Ox2-3 in. litter of leaves and twigs partly decomposed. O, 3 in. dark reddish brown fine granular mor, may quickly exceed amounts of available ele- pea e ments. On the credit side, shifting of nutrient Be2ce i h rl ond ast b cemented sand, balances is much easier in other soils of Bs 5 in. yellowish brown slightly cemented sand, than greater C on brownish yellow to yellow loose gravelly sand. weathering and clay content. Thus chemical disadvantages of yellow-brown pumice soils are This is a podzolised yellow-brown pumice soil readily corrected with fertilisers, permitting full and notable for strong acidity (pH 4-7) and low use of excellent physical properties. content of nutrients in the topsoil owing to severe their Addition of elements is usually not re- leaching. Horizons vary widely in development trace quired where farms include soils derived from ash according to age and the kind of native vegetation. beds older Taupo ashes or from sedimentary On high plateaus under tussock and low shrubs than marine rocks occur on hilly or steep lands (Dracophy//um spp.) soils such as Kaingaroa sand that part pumice has been (57g, Chapter 11) are formed on Taupo ashes. from which or all of the (Such of other soils with Their profiles are very shallow and generally eroded. associations yellow-brown pumice soils are shown by multiple have a thin humus-iron horizon with highly on soil maps.) Soils formed from compacted pumice subsoil. Exotic trees have been symbols the gravel phases of Taupo ashes are planted extensively on these plateaus and their sand and the included in Whakatane (moderately leached, roots penetrate and loosen the compact subsoil. the for 57c) and Matawai (strongly leached, 57e) soils. Such trees make the soil a better medium Gravelly bouldery pumice formed from plant growth physically: with some species en- and soils Taupo deposits are included in Wairakei leaching is decreased owing to the rapid breakdown thick the soils (57b). Tokoroa (57a) and Manunui (57d) of litter and cycling of nutrients; with others derived from pumice deposited by enleaching is increased and reduces the fertility soils are the after eruptions. They are of a soil already very low in plant nutrients. In streams on terraces the fertile Taupo and Ngaroma general it is desirable to grow trees that are effi. not as as the associated but with similar support cient in raising the fertility through rapid circula- soils topdressing they pastures are more readily managed and in tion of nutrients. that pastoral lands. Pongakawa Yellow-brown pumice soils are unusual in that time make excellent processes proceeding soils (83a) formed in swamps from mixtures of their soil-forming are simul- pumice in pumice and peat also respond when treated in a taneously with weathering of raw all similar manner. parts of the profile. Thus the development of horizons due to the conditioning effects of vegeta- 3. Central yellow-brown loams is out of step with low degree of weathering beyond bound- tion the In the Bay of Plenty district the of soil. The podzolisa- of the mineral material the aries of Kaharoa and Taupo ashes the soils are produced generation of can tion under one trees derived from older and more weathered pumice be by a change another vegetation. reversed to sands referred to as the Whakatane-Waihi series Responses applications of fertilisers are usually to of ash beds. Near the coast most of the soils are . but . as are affected by rapid are superficial they mapped as Katikati and Te Kaha soils (60a) and products weathering. An important feature of have the following general profile characteristics: is formation of allophane of the weathering the 8-12 in, black friable sandy loam with a very fine phos- and its adsorption of organic matter and granular structure, phorus and lack of retention of potassium (Chapter 8-10 in. dark brown friable sandy loam with a weakly dter downe n rl 7). These properties explain need for large the on a fine blocky quantities phosphatic fertiliser in of the early to massive structure.

51 3-2

Inland, with increasing rainfall and altitude the the ash mantle or where deposits are shallow and topsoils become browner, are usually 6 to 8 in. roots penetrate into the underlying weathered deep, and subsoils are yellowish brown friable materials. Generally this contribution is small sandy loams with a moderately developed nutty except on Coromandel Peninsula where the Waihi structure. These soils are more strongly leached ash deposits are more weathered and eroded and are mapped as the Waitekauri and Whaka- than the more recent ashes, and the strongly marama soils (60b). A similar degree of develop- weathered rhyolitic rocks are more exposed. ment is reached on the Whangamata soils (61a) Native forests were mainly podocarp-broadleaved derived from another series of ash beds containing on the lower slopes, grading into beech on higher much pumice lapilli. slopes, and provided a shallow mor humus layer Further increases in rainfall and decreases in to the soils. Small areas have been cleared for produce temperature Waihi and Matakaoa soils farming, but the general deterioration to low (60c), which are very strongly leached. A profile fertility after the initial flush from the forest burn under fern on a rolling slope on Waihi Plains is: and the aggressive invasion by ferns and shrubs pastoral 5 in. very dark brown sandy loam; friable; fine have resulted in general abandonment of granular structure, farming except where the steepland soils form a 4 in, le; fine granular small part of farm. Exotic forests have been s t tsw dae Ifri the 6 in, strong brown heavy sandy loam; friable; fine established on areas of lower altitude, but for the nutty structure, most part the steepland soils are best kept under 12 in. yellow heavy sandy loam; firm; fine blocky to protective forest for massive structure, water conservation. on yell wish brown silt loam grading pumice to The steepland soils are separated mainly on the basis of parent materials as follows- These soils, yellow-brown loams, are classed with Pihanga steepland soils (98a) from Ngauruhoe discussed in more detail with soils of South the the ash over older ashes and andesite Auckland district. Okareka steepland soils (98a) from Rotoma- South-west of Tongariro National Park, Tonga- hana ash over older ashes and rhyolite ashes beyond boundary riro cover the surface the Urewera steepland soils (58b) from Taupo Taupo They fine of ashes. are sands of mixed ashes over older ashes and greywacke and andesitic composition derived from rhyolitic Otanewainuku steepland soils (58a) from Taupo intermittent from Mounts Ruapehu eruptions ashes over older ashes and rhyolite Tongariro. Soils derived from deposits and these Tangatara steepland soils (58a) from Waihi such as Ohakune and Pokaka soils (63a) have ashes over rhyolite profiles generally similar to Egmont black loam (Chapter 11) but have a moderately developed TARANAKI WANGANUI medium granular structure in the upper 3 in, - brown yellow (Region B, Fig. 3 1 3) and (7 5YR and reddish - - - 4/2) (7-5YR 6/8) subsoil horizons. They are more The Taranaki-Wanganui region contains two leached then Egmont soils (64a), and with high strongly contrasting landscapes-steeplands and plateau rainfall (100 in.) and altitude (2,000 ft) near Mt. plains. West and south of the volcanic is Ruapehu the subsoils become less friable and show a wide belt of steeplands formed by deep dissec- distinct red and yellow mottles. These soils classed tion of soft marine sandstones and mudstones. yellow-brown gradually as loams are described more fully Ridges are narrow, their crests sloping with the soils of Taranaki. towards the coast from an height of about 3,000 ft to about 1,000 ft. In northern Taranaki the steep- 4. Steepland soils lands extend to the coast, but further south they Steeplands are common Taupo pass abruptly into plains. The largest is a ring throughout the - Bay of Plenty region as mountain ranges, as plain rising at a steadily increasing rate to 2,500 ft steep country along fault scarps, or as volcanic around the 8,260 ft cone of Mount Egmont (see ridges and cones. They have been smothered by ash shower map, Fig. 1*2*1). Below 500 ft the showers of volcanic ashes, which dominate their ring plain grades into narrow coastal terraces soil properties. The thick porous mantle of the that meet the sea in low cliffs and extend eastward little weathered Ngauruhoe, Tarawera, or Taupo beyond Wanganui into the Manawatu region. ashes has been protected by forests that either Annual rainfalls are mostly 60 to 100 in. or more survived the eruptions or were re-established but are 45 to 60 in, in a narrow strip along the quickly afterwards and allowed little run-off or south coast. At times high-intensity falls cause surface erosion. The underlying rocks contribute widespread erosion on steeplands and very rapid to the soils where recent landslides have removed rises in river levels. The rivers flow mainly in

52 3-2 steep-sided deep channels to the coast and, in decreases and between Toko and Lepperton contrast to the Wairarapa-Gisborne region, do moderately leached hill soils are associated with not have wide and highly fertile flood plains. The strongly leached New Plymouth soils. In a seg- native vegetation was dominantly broadleaved- ment of the ring plain west of Mount Egmont podocarp forest (tawa, rimu, matai, totara) now the deposits of a huge mudflow have a shallow cleared entirely from the plains and extensively coating of Egmont ash. These deposits are marked from the steep slopes. Scrub and fern grew in a by numerous small conical hills separated by narrow coastal belt. flattish land and the soils are classed as Warea Soils of the district belong largely to two groups: soils (64a) near the coast and Kahui soils (64b) central yellow-brown loams, and steepland soils inland. Soils from andesitic volcanic ash on sites related to central yellow-brown earths. Central influenced by high ground-water levels are in- recent soils from alluvium, gley, and organic cluded with the Rahotu soils (87b). soils occupy only small areas in lowland sites. These yellow-brown loams have some out- standing characteristics. Their friability and free 1. Central ye/Iow-brown loams drainage provide excellent physical conditions for grazing The yellow-brown loams are friable free- plant growing and in a wet climate; the draining soils covering the plains and the rolling soils are not sticky, and when moist they absorb and moderately steep slopes within the hill country. large amounts of water without swelling. On the They are derived from volcanic ash erupted from other hand they have a high requirement for Mount Egmont during numerous eruptions of the phosphorus due to high retention by allophane, years groups last 50,000 or more. Four of ash the dominant clay constituent, and a requirement showers are recognised as soil-forming and in for potassium that increases with agricultural use decreasing order of age are named Egmont, owing to low retention of potassium by the allo- Stratford, Newall, and Burrell ashes. They are of phane. andesitic materials, gravelly near the mountain 2. Central recent soils from volcanic ash but grading outwards into sand and silt textures. The recent soils derived from gravelly and Dark bands under Egmont ash beds in road cut- the sandy andesitic materials erupted from Mt. Eg- tings indicate soils formed on older ash beds between 200 and 400 years ago (p. 9) are during periods of quiescence and buried by later mont mapped as Burrell soils (960). They are showers. The ash beds rest either on bouldery collectively in Egmont National Park and are of mudflow deposits or on marine sediments. mainly the little importance farming. A profile of Burrell Egmont (64a), Patua (65b) and Stratford (65a) to loam under kamahi forest at 3,000 ft on eastern soils are described in Chapter 11. Egmont black the of Mount Egmont showed: loam is a moderately leached yellow-brown loam slopes dark grey granular developed from Egmont ash. It occurs extensively O 4 in. very mor, A 4 m. very dark grey granular loam with gravels, in plains from Okato coastal south where annual BC 12 in. dark reddish brown loam coating andesitic rainfall is generally less than 60 in. North from gravels with thin soft iron pan at base, gravels with strong brown and reddish Okato, where rainfall is between 60 in, and 80 in. on brown stains. and the native forest contained a higher propor- 3. Steepland soils tion of podocarp species than further south, the New Plymouth soils (65a) have developed from Steepland soils occur on Mount Egmont, on Kaitake Egmont ash. They are strongly leached (24% the adjoining Pouakai and ranges, and half Taranaki. These base saturation in A horizon) and have well extensively in the eastern of by but developed medium nutty aggregates with thin areas were once covered ash showers, the been by from brown coatings in the B horizon. Under the higher deposits have removed erosion rainfall and mor-forming vegetation on the lower many steep slopes, exposing underlying rocks to formation. On Mount Egmont slopes of Mount Egmont the New Plymouth soils soil and adjacent lavas, grade into Patua soils, which have thinner, more ranges these rocks are andesitic and the best acid topsoils induced by slower decomposition of soils are stony and rocky. They are retained organic matter, and distinct brown coatings on in forest. Taranaki nutty aggregates in the subsoils. Soils derived On the steeplands of eastern the soils from Stratford ash show a similar sequence, the are derived from a mixture of volcanic ash and least leached soil being Stratford coarse sandy weathered marine sandstones or siltstones. The past loam and the most strongly leached, Inglewood ash contribution varies with the amount of coarse sandy loam (65b). erosion and is generally between 0 and 50% of This pattern holds for soils on undulating land. the soil. Thus profiles differ considerably within profile from As slopes increase, the effectiveness of rainfall short distances. An example of a a

53 3*2 steep slope under bracken fern and broadleaved from 35 to 45 in. on the lowlands increasing to shrubs is: 60 in. on steeplands below 1,200 ft and to 100 in. 2 in. dark brown friable fine sandy loam with a fine and more on the mountain ranges. Temperatures granular structure, below an altitude of 1,200 ft are generally mild, 7 in, brown friable fine sandy loam with a mixed nutty favourable growing for pasture and granular structure, and to a season on yellowish brown sandy loam with many yellow of 10 to 11 months. Broadleaved-podocarp forests an t edraments p singr assive sandstone were originally extensive, grading into beech forest above 1,000 ft and into lowland shrubs and swamp- Except for a low level of available phosphorus, land vegetation near the coast. Most of the land the soils are moderately well supplied with plant below 1,200 ft is now in pasture and used for nutrients. Their main problem is not fertility but breeding and fattening of sheep and cattle or for stability; for the boundary between soil and rock is distinct and bonds between are weak. If them S 1sn f the region are discussed under five forest is for pastoral farming the native removed headings: the strong roots of the trees are replaced by the 1. Central yellow-grey earths (and intergrades);. finer and generally shallower roots of the grasses. 2. Central yellow-brown earths (and mtergrades); The surface loses its layer of tree litter and becomes 3. Steepland soils; 4. Central yellow-brown sands; more compact and less absorbent of rainfall. 5. Central recent, gley, recent, and organic soils. Much water enters cracks formed by shrinkage of soils in dry periods, and this water weakens co- 1. Central yellow-grey earths (and intergrades) hesion in the subsoil. Hence slip erosion increases Yellow-grey earths occur on flat to undulating under grassland, its significance varying with the terraces and on rolling and hilly lands of those exposed materials. Where siltstone is exposed parts of the Manawatu district with annual rain- (Mahoenui soils, 35b) it weathers fairly rapidly falls of 32 to 45 in, and a slight summer dry a new soil is formed within. one or years -and two season. Their general characteristics are illustrated and can be maintained in grass. In Taranaki and by Marton silt loam (14a, Chapter 11). Profiles upper Wanganui districts, slips commonly expose are similar in colour, structure, and consistence sandstone (Whangamomona-Mangamahu 36a, to Matapiro soils (Chapter 11) of the Wairarapa- Moumahaki-Mokau soils 36b) that weathers Gisborne region but differ notably in more abund- slowly, and formation of a new soil is corres- ant gleying with fine concretions in the lower A pondingly. slow. Fern and shrubs invade tend to horizon, and in higher clay content, less compac- bare areas before grass is established, and farmers tion, and greater fragmentation of the fragipan. have the double problem of erosion and weed These differences are consistent with the more control. Where grazing can be rotated in conjunc- frequent waterlogging in the Manawatu yellow- tion with adiacent. yellow-brown loams, problems grey earths. The concretions have a high content of using these steepland soils are much fewer and of manganese dioxide. Although these soils dry pastoral farming has been generally successful. out in summer, they need drainage to remove Otherwise there have been many failures. The excess water that accumulates in winter. Related steepland soils of this region are capable of grow- soils are present in Wairarapa and Canterbury. ing excellent crops of timber trees not only to The yellow-grey earths of the Manawatu region supply local timber but also to reduce erosion, are considered to have been formed from wind- especially of soils developed from sandstone. blown dust (loess) blown from river beds and coastal sand dunes. Differences between soils MANAWATU-WELLINGTON the are due mainly to the rate of accumulation and (Region C, Fig. 3 1 3) is - - texture of the loess. Near the rivers the loess The Manawatu-Wellington region has a central fairly thick on flat and undulating land and lowland of plains and recently dissected terraces ranges from fine sandy loam to silt loam in texture. bordered to the north, east, and south by hilly Accumulation was fairly rapid and there was little and steep land. On the western side there are soil development as the loess was deposited steeplands and coastal terraces (adjacent to the (Tokomaru silt loam, 14a). Marton silt loam Taranaki-Wanganui region) at the northern end, occurs on undulating land further away from the a long stretch of sand dunes bordering the Tasman rivers where the loess is thinner and the texture Sea in the central part, and steeplaxids extending is finer. On rolling and hilly slopes the loess right to the coast at the southern (Wellington) end. deposits have largely been removed by erosion The steeplands on the eastern side rise to the crest and the soils are formed on old alluvial or marine of the Ruahine and Tararua ranges bordering the sediments. The soils from sandstone (Raumai, 14b) Wairarapa-Gisborne region. Annual rainfalls range and those from siltstone (Halcombe, 14b) have

54 3-2

parent profile features similar to those of the Tokomaru greywacke. The differences in material are Kiwitea or Marton soils on adjoining terraces but are less reflected in the higher requirement of the mottled and have less uniform horizons. soils for phosphorus and potassium and the better All of these soils are moderately leached and response of the Korokoro soils (32b) to molyb- gradual low in available phosphorus. They show a denum. Under the cooler and wetter climate of increase in percentage base saturation in the lower uplands above 1,000 ft, Belmont and Ramiha greywacke-loess, horizons and a narrowing of the Ca/Mg ratio. (33c) soils are formed on mixed Under pastoral farming they respond well to solifluction, and ash deposits. Belmont soils are phosphate and lime, and responses have also been less weathered but more leached than Judgeford pasture production. observed to potassium and molybdenum treat- soils and have a lower ments. Farming is mainly based on lamb fattening, Associated Renata soils are very strongly en- with some dairying and wheat, barley, and pea leached and profiles show distinct clay coatings cropping. on subsoil aggregates with local tendencies to Soil intergrades between central yellow-grey bleaching of the upper subsoil and formation of podzolisation. and yellow-brown earths (palli-fulvic soils) are a thin iron pan indicative of weak extensive on the coast of the Wellington district The sequence of soils, Judgeford-Belmont-Renata, but elsewhere are only in small areas. Annual is correlated with a decrease in mull-forming increase in rainfalls vary between 40 and 50 in. Upper horizons trees (tawa) and an mor-forming trees profiles yellow-grey kamahi) in native of are similar to those of (rimu, miro, the vegetation. earths but lower horizons are more yellowish Where forests on Renata soils are replaced by podzolisa- brown, less mottled, and have a coarse nutty or pasture, there is no evidence of active blocky structure. The properties of these inter- tion nor of soil erosion. grades are well illustrated by Porirua-Paremata Taita soils (34b) are developed under mor- soils (21b, Chapter 11) which are more leached forming beech forest from deeply and strongly than modal yellow-grey earths but dry out to a weathered greywacke. The area has a mild humid lesser extent. With phosphate and lime these soils climate similar to that under which the Judgeford- provide excellent pastures for sheep or cattle Korokoro soils have developed, but owing to breeding with some fattening. downwarping of the land late-Pleistocene erosion has been considerably less. In many places materials 2. yellow-brown (and Central earths intergrades) underlying the C horizon exhibit red weathering, is be of a In the Manawatu-Wellington region, yellow- which considered to a consequence present. brown earths and intergrades are developed on past climate warmer than at Taita soils for undulating, rolling, and hilly land receiving annual (Chapter 11) are notable their strongly acid litter, in subsoil, rainfalls of more than 45 in, and having no well thin topsoil, coarse structure the phosphorus, defined summer dry season. They are in valleys strong leaching, very low available low molybdenum, and close to the mountain ranges along the eastern total calcium, response to high is kaolinitic. side of the district and on hills near Wellington. clay content, much of which The general properties of similar yellow-brown They require considerable topdressing and careful pastures but grow earths in the Wairarapa-Gisborne region are management to maintain forest. described on p. 58. excellent exotic They are subject to vigorous is protected by Most of the soils within the group are derived sheet erosion unless the surface from greywacke materials, in some places directly dense pastures or thick forest litter. from rock and in other places indirectly from 3. Steepland soils solifluction, water-laid, or windblown deposits from erosion of greywacke. Also, there are im- Steeplands are extensive in northern and eastern portant differences related to the age of the surface parts of the Manawatu district, and throughout generally and to additions of volcanic ash to the sediments. the Wellington district. The soils are Judgeford silt loam (32b, Chapter 11) and shallow, and many have a colour B horizon over They free- Levin soils (66a) are examples of yellow-brown weathering rock (clini-fulvic soils). are earths and intergrades developed from mixed draining friable soils with differences related greywacke and volcanic ash sediments under a chiefly to parent rock and to climate. blue Taihape mild humid climate. They are moderately leached, Turakina soils (23a) from siltstone, and when topdressed with phosphate, lime, and soils (23a) from grey siltstone, Whangaehu soils Pohangina molybdenum they will maintain highly productive (21a) from fine sandstone, and soils in pastures. Similar soils are Kiwitea silt loam (66a) (23d) from coarse sandstone are extensive the containing a higher proportion of volcanic ash northern Manawatu district. They developed under and Korokoro silt loam derived directly from forest and annual rainfalls of 45 to 60 in. Under

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growing plants pasture, run-off is rapid and the soil-moisture to moderately leached, but for conditions for pastoral growth are uneven and leaching losses are more than offset by improved in resemble those of the intergrade between yellow- physical condition due to increases organic particles dust grey and yellow-brown earths rather than the matter and accumulation of fine of adjacent yellow-brown earths. Nutrients other that increase the moisture-holding capacity and than phosphorus are moderate to high, and, resistance to erosion. The more weathered soils with topdressing, excellent pastures for sheep and and those with high water tables are capable of pastures for dairying cattle grazing can be obtained. The chief farming maintaining high-quality phos- problem is instability due in part to the effects and fat-lamb farming. Regular dressings of potash of replacing forest with grass. Slip erosion becomes phate and are required, and the wetter common, and its significance to the soils depends soils need drainage. Trace-element deficiencies of have been mainly on the nature of the surface exposed. On copper, cobalt, and selenium reported drained Turakina and Taihape soils the exposed surface on some farms. On the more excessively is prefer- is firm but weathers quickly to provide a foothold yellow-brown sand soils exotic forestry (54a) for plants, and where seed is sown on slipped faces able to pastoral farming. Foxton soils are dunes bordering the loss of grazing is small. On Whangaehu and formed on slightly consolidated grey black more particularly Pohangina soils the exposed the coast. They have a dark to very yellowish firm surface is soft and tends to be gullied by run-off friable topsoil over brown slightly grey loose before plants are established. Careful pastoral sand, which grades down into sand. becomes darker in management is required to lessen occurrence of Towards Taranaki the sand ironsand. slips and gullying in stream channels. In the upper colour with increasing amounts of pastures reaches of the Rangitikei and Wanganui valleys Fair-quality of cocksfoot, ryegrass, and but where annual rainfalls exceed 60 in., Taihape subterranean clover can be maintained, with if soils grade into Mahoenui soils and the pastoral little growth in summer. Wind erosion occurs grade problems are increased owing to the lower level the topsoil is breached. These soils coast- of soil nutrients and more aggressive growth of wards into loose sand drifts, large areas of which grass, fern and manuka on surfaces exposed by erosion. have been stabilised with marram tree years. The effects of climate and vegetation on steep- lupins, and pines over the last 60 Pukepuke land soils are also illustrated by differences in soils (54b) are associated with Foxton soils; they plains best soils derived from greywacke and are considerable have developed on sand and make the pastoral lands district. They consist of on the Ruahine and Tararua ranges as well as of the grey yellowish near Wellington. Makara soils (35a) developed deep black sand over sand with on steep slopes under mull-forming broadleaved- brown mottlings ranging from rare to abundant podocarp forest are moderately leached and with in the subsoil down to 24 in. With shallow drainage hold topdressing make excellent pastoral land. Ruahine and regular topdressing these soils excellent pastures. They grade soils (37b) developed under mor-forming beech and ryegrass and white clover profiles podocarp forests of higher-rainfall areas are inland into Carnarvon soils (54c) in which strongly leached and difficult to maintain in have a greyish brown sandy loam topsoil over pasture but grow excellent crops of timber. Rimu- grey sand with iron concretions. With drainage taka soils (37b) formed under mor-forming beech and topdressing Carnarvon soils also maintain in plains or kamahi forests, with higher rainfalls and cooler excellent pastures. Depressions the sand by peaty loam over grey temperatures than Ruahine soils, have very low are occupied mellow draining depressions be fertility. On these soils the growth of vegetation is sand. In these care must slow, and they are best retained for protection taken to avoid lowering the water table of adjacent limit- forest to conserve water supplies. sand plains sufficiently to make moisture a ing factor for pasture growth. 4. Central yellow-brown sands 5. Central recent, gley recent, and organic soils The yellow-brown sands are formed on coastal plains lands sand drifts covering about 250,000 acres. The Flood and swamp occupy consider- but areas consist of complexes of dunes, sand plains, able areas of the Manawatu Plains are restricted in bottoms in Wellington and peat swamps with a very wide range of drain- to small areas valley the derived from age conditions. Soils on the younger sand drifts district. The soils are alluvium profile lakes have bordering the coast show little or no deposited by rivers, streams, or and a development and except on sand plains where wide range of texture and organic-matter content. frequently over short the water table is high they are droughty and Soil characteristics change unstable. Further inland the soils formed on older distances, and a detailed map is required to show pattern Major differences sand drifts are more weathered and slightly the of soil types. soil

56 3-2 are related to the conditions of accumulation, and of 7,500 acres to be reclaimed. Volcanic ash from on this basis three sets of soils are separated- eruptions in the Taupo-Rotorua district has been Manawatu soils (95a) on free-draining flood plains, deposited over the lands north of Napier and is Kairanga soils (95a) in the slow-draining parts of soil forming on dissected plateaus and terrace lands. plains, peaty (83a) has the and the Makerua soils in Climatically this region a wider range of swampy depressions once permanently covered conditions than other parts of the North Island. with water. Mean annual rainfalls lie mostly between 35 and Manawatu soils are friable deep brown to 45 in. on lowland areas of Hawke’s Bay and yellowish brown sandy loams and silt loams Wairarapa and rise to more than 100 in. on the present on river levees. They are highly fertile western ranges and in northern Gisborne. On soils suited to a wide variety of cropping or pastoral lowland areas east of the mountain ranges rainfall uses. The closely associated Kairanga soils range in is unevenly distributed, and there is a strong texture from sandy loams to clays with a fairly tendency to dry periods in summer and autumn distinct change in colour downward from greyish with droughts in lower rainfall areas. Dry westerly brown topsoil to grey subsoil. The subsoil shows winds are common in southern Hawke’s Bay and a variable amount of rusty coloured mottles. Wairarapa and reduce the effectiveness of the Nutrient status is high, and with adequate drainage rainfall. Occasionally high-intensity rains cause the soils make highly productive land for pastures widespread slip erosion and flooding. Downpours or annual cropping. Surface drainage is slow, and of 3 in. per hour and of 39 in, in 3 days have the surface becomes puddled by heavy stocking. been recorded. Temperatures are generally warm growing. When wet the soils are excellent for flax to mild but are cool on lands above 1,000 ft. Makerua soils have developed in swampy places The native vegetation was mainly broadleaved- from dead vegetation mixed with some fine- podocarp forest grading into beech forest on textured mineral alluvium deposited during floods. poorer soils above 1,200 ft. Coastal forest and They are moderately fertile but require careful bracken fern covered most of the coastal hills, drainage before they become useful for crops or rolling land, and plains, where annual rainfall is pasture. With drainage and use the surface gradual- less than 45 in. ly sinks and soils formed from forest peats expose The soils are described in five divisions: layers logs successive of stumps and that are costly 1. Central yellow-grey earths (and intergrades); been to remove. Some areas, though, have over- 2. Central yellow-brown earths; 3. Steepland soils drained dry in and now out severely summer. related to central yellow-brown earths; 4. Yellow- However, Makerua soils that have been drained brown pumice soils; and 5. Central recent, gley have land for dairymg and stumped made excellent recent, and saline gley soils. The soils of these gardening. or market groups are not sharply separated and intergrades are included with the soils of the nearest group. WAIRARAPA-GISBORNE 1. Central yellow-grey earths (and intergrades) (Region D, Fig. 3-1-3) Yellow-grey earths and associated soils are The Wairarapa-Gisborne region, 300 miles long developed in those parts of Hawke’s Bay and and 50 miles wide, borders the Pacific Ocean from Wairarapa with a well defined dry season and an Cape Palliser to East Cape. It is dominantly annual rainfall of less than 45 in. distributed over steep and moderately steep land produced by fewer than 150 rain days. They are derived mainly recent and rapid dissection of soft Tertiary and from lightly consolidated alluvial, marine, or Pleistocene sediments, and by slower dissection wind-blown sediments, but a few soils are formed of older and harder greywacke rocks of the moun- on older sedimentary rocks. greyish tain ranges on the western side of the district. The soils have brown friable topsoils South from Napier the two types of country are and pale yellow firm subsoils with weakly de- separated by a narrow lowland of terraces con- veloped aggregates and marked line mottling. sisting of detritus of the Last Glaciation, and In soils formed from lightly consolidated sedi- Holocene erosion products. At the northern end ments the subsoil below 18 in, is compacted to a of the lowland these terraces widen out into the fragipan (illustrated in PI. 7) with widely spaced Heretaunga Plains of Hawke’s Bay, and at the vertical cracks. These cracks provide channels for penetration southern end into the Wairarapa Plains. The dis- water and root and are usually bor- trict has a long history of earth movements, seen in dered by thin pale grey and brown layers. In numerous fault scarps and flights of terraces. The intergrades towards the yellow-brown earths the most recent uplift of 1931 raised the land around blocks of fragipan are smaller and the fragipan Napier by about 5 ft and allowed a shallow lagoon grades into a finely reticulate mottled horizon.

57 Clay mineral analyses show that the soils are for fattening sheep and cattle. Gwavas soils (22a) moderately weathered and have a preponderance are similar stony soils but on rolling and moderately of clay vermiculite and illite. Nutrient content steep land unsuited for irrigation. At present they differs with parent material and extent of leaching. are mostly in poor-quality pastures or in exotic Available phosphorus is generally low and the forests. ratio of calcium to magnesium decreases down the Steepland soils associated with the yellow-grey profile. The soils are suited to cropping or to earths, and intergrades with yellow-brown earths, grazing. High stock numbers may be carried in are divided mainly on the kind of parent material. spring and autumn but can cause serious puddling Taihape steepland soils (23a) are developed on in winter. siltstones, Tangoio steepland soils (23d) on sand- Matapiro silt loam (13a, Chapter 11) is a well stones, Whareama steepland soils (23b) on mud- developed yellow-grey earth extensive in Hawke’s stones, and Mataikona steepland soils (23c) on Bay. Associated soils on more sandy materials argillites. They are shallow fertile soils that drain are here included in the Crownthorpe soils (13a), freely, and their pastures suffer from drought. and those on the argillite rocks in the Mangatarata- The slopes are apt to slip badly because of water Waipawa soils (13b). They are all weakly to entering shrinkage cracks opened up in dry weather. moderately leached and have no known serious On the Whareama and Mataikona soils gullies deficiencies of trace elements. Plant growth is may develop on surfaces exposed by slipping. limited by drought. Halcombe and Marton soils 2. Central yellow-brown mapped in the Wairarapa district and described earths with the Manawatu-Wellington region occur for Yellow-brown earths, occurring under forest the most part under somewhat higher rainfall than and an annual rainfall exceeding 45 in., are very Matapiro soils. extensive on hilly land north of Gisborne and Soil intergrades between yellow-grey and yellow- between Takapau and Masterton. They are formed brown earths occupy extensive areas of Hawke’s from sediments ranging from claystones to con- Bay and Wairarapa around the yellow-grey earths glomerates and from soft bentonitic mudstones to generally and along the coast. Profiles are similar hard greywacke sandstones.Weathering is not as in yellow-grey but hori- colour to those of earths, advanced as in Northland, so, excluding soils zons are less distinct and less mottled, and subsoils derived from claystones and mudstones, the silt have moderately developed medium-sized struc- and sand fractions exceed those of clay, and the tures. Compared with yellow-grey earths formed clays of these central yellow-brown earths have from similar materials the soils are more leached less kaolin and more vermiculite than northern and have a less developed fragipan, and plants yellow-brown earths. In profile, topsoils are suffer drought less frequently and for shorter greyish brown to brown friable to firm loams with periods. Illitic clay minerals dominate the clay a moderately developed medium to fine nutty fractions except in Wanstead soils, which have structure. The contrast with the yellow-grey earths montmorillonitic clays derived from bentonitic is more noticeable in the subsoils, which are mudstone. Wanstead soils (20a) are sticky clays yellowish brown firm clay loams with moderately and are highly fertile but are unstable. Atua soils developed medium nutty structures and rarely (20a) are silt loams over clay loams derived from any mottling. Drainage is slightly impeded to free siltstone. They are extensive on hilly land in and under the moderately high rainfall there is a Hawke’s Bay and Wairarapa, and with light continual loss of plant nutrients. Most of the soils phosphate topdressing maintain excellent pastures have low natural fertility, but having good physical for sheep and cattle breeding and fattening. conditions they respond well to fertilisers and can Maraetotara soils (21a) are sandy loams on be made into moderately to highly productive sandy clay loams and have moderate to low natural pastoral land. Under cultivation, soil aggregates fertility but are easily converted to good-quality break down rapidly, and the yellow-brown earths pastoral land with topdressing. However, they are thus not suited to regular cropping. are prone to serious slip erosion. Tinui soils (20c) Differences in properties between soils of the principally parent are silt loams on stony silt loams derived from group are due to climate, argillite. They cover extensive strips of hilly land materials, and native vegetation. Kourarau and used for grazing but are prone to serious gully, Waimarama soils (31a) are developed on cal- slump, and sheet erosion. Takapau soils (22a) careous siltstones and sandstones and are weakly occupy gravelly plains built up by rivers, but now to moderately leached. Makotuku and Whetukura above flood level. Topsoils are very friable and soils (31b), formed under a similar climate but liable to wind erosion under cultivation but with from non-calcareous sandstones are moderately to irrigation and topdressing hold excellent pastures strongly leached. On all of these soils the native

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generally and vegetation was mull-forming broadleaved-podocarp coastal hills. The soils are shallow yellowish forest. The Ngaumu (34a) and Tuhitarata soils have brown topsoil and a shallow .a (34b) developed on hard sandstones under a brown subsoil (colour B horizon) over weathering pieces common mor-forming beech forest and are strongly leached. rock. Small of weathering rock are friable A profile of Kourarau silt loam under pasture throughout the profile. The soils are and depends on a rolling slope in the Wairarapa is: free draining, and their nutrient content on the parent rock and the climate. Nutrients are A 7 in. brown silt loam; friable; moderately devel- high in from (Pahiatua-Mahoenui oped fine granular to nutty structure; soils siltstones abundant roots; indistinct boundary, soils, 35b), mudstones (Tuparoa soils, 36c), and B 8 in. dark yellowish brown silty clay loam; firm; basalts (Potikirua soils, 80a), moderate in some soils strongly developed fme nutty structure; from (Ruatoria, 36c), greywacke (Pa- many casts of topsoil; many roots; indis- argillites and bios haoa soils, 35a), low in soils from sandstones (Man- few C 12 in. e on silty clay loam with gamahu soils, 36a) and from mixed volcanic ash fine pale grey mottles; weakly developed fine blocky structure grading into massive; and greywacke (Ruahine, 37b and Raukumara soils, 37a). The effect of climate is illustrated in on ew g calcareous sandstone. greywacke, tTe the sequence of steepland soils from profile Ngaumu loam pasture A of silt under in which Pahaoa soils grade into Ruahine soils a rolling slope in Wairarapa is: in- on the and these in turn into Rimutaka soils with proportion A 7 in. greyish brown (10YR 5/2) silt loam; firm; creasing rainfall, altitude, and of devedopedi edgranulnatrostru ureemy All mor-forming trees (beech, miro, kamahi). of oepakl developed fme nutty structure with many these steepland soils are subject to soil erosion cast granules; many roots; irregular distinct of various kinds (Chapter 4 6). - boundary pastoral The more fertile soils are suitable for B 10 in. yellowish brown (10YR 5/6) silty clay loam; fine for purpose, but firm; moderately to strongly developed farming and are widely used that pu cs many roots; the less fertile are generally unsuitable and are plstr ct bu ds better for forestry for production or C, 10 in. pale yellowish brown (10YR 6/4) silty clay used timber loam; firm; moderately developed medium conservation of water supplies. blocky structure; few roots, C2 18 in. but with many distinct pale olive RS above 4. Yellow-brown pumice soils and strong brown mottles in cracks, on pale olive (5Y 6/3) muddy sandstone. Yellow-brown pumice soils are very friable or gravelly soils formed from volcanic ash deposits On terrace and rolling land bordering the western on dissected plateaus and lands of northern ranges from Kereru to Featherston are extensive terrace friable Hawke’s Bay and Gisborne. The deep soils are areas of yellow-brown earths that are more friable similar Taupo soils of the Taupo-Bay of than on the eastern hills. These more soils to the Glacia- Plenty and with similar and are developed from sediments of the Last region, topdressing pastures places include consolidation will maintain good tion and in some volcanic ash. they They grow good Dannevirke silt loam (Chapter 11) illustrates the for sheep or cattle. will also is needed in region. Where properties of these soils. Its clay fraction is less timber, which this is less 12 in. deep, plant roots weathered, containing less vermiculite, more chlor- the volcanic ash than nutrients from underlying weathered ite and more allophane than yellow-brown earths obtain some nutrients brought surface such as Judgeford silt loam. On dissected older rocks, and these to the lower so raise fertility soils require less terraces (Matamau soils, 33b) and terrace the that the for good pastoral land. land (Kopua soils, 33b) associated with Dannevirke treatment conversion to Soils from are common on hilly lands soils (33a), the silt mantle is shallow and the soils shallow ash combinations of Atua or include 5% to 50% of gravels and stones. Phos- and are mapped as Whetukura Taupo soils. They are also ex- phate retention is high in all these soils, and thus and on steeplands, where are mapped in heavier rates of topdressing are required than on tensive they with Taihape or Mahoenui soils. other yellow-brown earths, though not as much combination Deficiencies of elements in areas are as on the yellow-brown loams. The soils are trace these less distinct because it is rare for a farm or even widely used for dairying. from a field to have soils formed wholly the 3. Steepland soils related to central yellow-brown volcanic ash. earths gley 5. Central recent, gley recent, and saline soils Steepland soils related to yellow-brown earths This group includes soils of river flats, swamps, occupy about 45% of the total area of the dunes, dominant Wairarapa-Gisborne region. They occur exten- lagoons, and sand where the process is accumulation. Profiles show gradual sively along the western side of the region and on

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differences in such properties as colour, content of basins and central ranges were covered in manuka organic matter, base status, and available phos- scrub probably induced by early fires. Swampy phorus. Sand grains are clean and show little flood plains carried kahikatea forest, which also evidence of weathering. On free-draining sites the grew on the margins of peat swamps around the soils (Manawatu and Esk soils, 94a) are friable central area of sedges, rushes, and mosses. and have soft granular aggregates that allow The soils of the South Auckland region are free movement of air, water, and roots. They can conveniently described in four divisions: 1. Central be used without difficulty for many purposes- yellow-brown loams; 2. Central brown granular pastures, orchards, vegetables, and most crops. loams; 3. Central and northern yellow-brown With careful management slower-draining mem- earths; 4. Central recent, gley, and organic soils. bers (Kairanga soils) can be made equally produc- Central yellow-brown loams tive after drainage improves the internal air 1. to water balance. On lagoon lands reclaimed from Yellow-brown loams are friable free-draining tidal flooding the removal of salt by drainage soils derived from fine-textured volcanic ash of allows establishment of pastures for grazing. The rhyolitic or andesitic composition and of Holocene properties of a soil on a lagoon raised by the or late Pleistocene age. They extend from the Napier earthquake of 1931 are illustrated by Taranaki, Taupo, and Bay of Plenty districts Ahuriri silt loam (89a, Chapter 11). northward over rolling and hilly lands to near Raglan, Hamilton, and Morrinsville. Further north the rolling and hilly lands are covered with SOUTH AUCKLAND older subaerial deposits (Hamilton ashes), and yellow-brown loams occur on water-laid deposits (Region E, Fig. 3 1 3) - - of volcanic debris forming flattish terraces that South Auckland extends northward from the have been above flood level for thousands of boundaries of the Volcanic Plateau and Taranaki years. Topsoils are black to brown, are very to Auckland City. In contrast to more southern friable, and have a soft granular to crumb struc- regions the relief is subdued, few areas being ture. Subsoils are brown to yellow, very friable, above 1,000 ft. Wide valleys and low rolling hills and have a weakly developed nutty structure. occupy the central part, and more hilly and some These soils are older and more weathered than steeplands on the eastern and western flanks. yellow-brown pumice soils but are younger and All of the region has been covered in the past less weathered than brown granular loams. Like by showers of fine rhyolitic or andesitic volcanic the yellow-brown loams of Taranaki they are ashes from eruptions earlier than those that pro- not sticky, they absorb large amounts of water duced the yellow-brown pumice soils. In addition, without swelling, and have a high requirement for pumice has been carried down into the district phosphate and potash. Such properties are at- general by the Waikato River and its tributaries and tributed to the dominance of allophane and deposited, with other sediments, on terraces. The absence of micaceous clays. Chemical disadvan- volcanic ash beds decrease in thickness northward tages are more than offset by physical properties and there is a distinct change in age about a line favourable for grassland farming. The yellow- good across the district through Hamilton. South of brown loams bring the light texture and this line soils on rolling lands are derived chiefly aeration and drainage of southern soils into a growth, from Mairoa or Tirau ashes or a mixture of these; warmer climate. Hence the rapid spring produc- north of the line many soils are formed from the quick response to summer rains, and high older Hamilton ashes. On many hilly lands most tion per acre of pastures in the Waikato district. of the ash beds have been eroded away to expose Hand in hand with this increased production come soft Tertiary mudstone, limestone, sandstone sedi- stock problems related largely to the chemical ments, or deeply weathered Mesozoic greywacke processes of rapidly growing pastures and bio- rocks. Coromandel Peninsula on the eastern flank logical decomposition of grazing residues. consists of a complex of andesitic and rhyolitic The group embraces numerous soils produced lavas. The climate is warm and humid, with a chiefly by differences of climate and vegetation, well distributed rainfall of 45 to 80 in. per annum parent materials, and slope. Climatic differences and mean annual temperatures of 560F. Mixed produce two major subdivisions of enleachment. broadleaved (tawa) and podocarp (rimu) forests Moderately leached yellow-brown loams occur in were extensive on rolling and hilly lands, and some regions below 1,000 ft with annual rainfall under kauri occupied hilly land on both sides of the 65 in. They are illustrated by Tirau sandy loam These Firth of Thames. At the time of European settle- (62a) and Egmont silt loam (Chapter 11). phosphate, ment most of the Hamilton and lower Waikato soils have low bulk density, respond to

60 3-2 potash and lime, and have very high phosphorus kaolinitic clays. In this they differ from yellow- retention. Differences in individual element con- brown loams, which contain allophane. Moisture tents between the soils are due to variations in range tends to be wide, and summer dryness can thicknesses of older ash deposits that can no be a limitation to high production. Hence irriga- longer be recognised. Similar soils and their tion can be beneficial to dairying, fattening, market respective parent materials are Otorohanga silt gardening, or grape growing, which are the main loam (62a, Mairoa ash), Maihiihi silt loam (62b, uses for these soils. They exhibit high phosphate Maihiihi ash), Te Kuiti Mapiu hill soils (62c, retention and respond phosphate - to topdressing. Mairoa ash over rhyolite and sandstone), and Lime and molybdenum are also required on the Horotiu sandy loam (66c, alluvium from volcanic more developed soils. debris). The native vegetation was dominantly Brown granular loams, characterised by less broadleaved forest, fern, or manuka, now all developed horizons, are illustrated by Patumahoe- replaced by grassland for dairying, sheep fattening, Onewhero clay loams (73a) formed under broad- or breeding. With increasing altitude and rainfall leaved forest on undulating lands in the lower there is a gradual decrease in thickness of topsoil Waikato and Pukekohe districts. They are more to 3 in, and general increase in reddish hue and friable and have a more even moisture content size of aggregates in the subsoil. At higher altitudes than the firm compacted Hamilton and Naike Podocarpus spp., notably rimu, were more common clay loams (73b, Chapter 11). Soil horizons are in the native forest and resulted in a mosaic of more distinct in the Opita-Churchill soils (73c) mull- and mor-forming trees. Characteristics of where topsoils tend to be grey and have weakly strongly leached yellow-brown loams (Mairoa- formed aggregates, and subsoils tend to be yellow Te Rauamoa soils, 62d) are shown in the descrip- and have prismatic structure. These soils grade tions and analysis (Chapter 11) of Waiteti loamy into and contain podzolised yellow-brown earths sand (57f) for soils derived from mixed rhyolitic (Maramarua soils, 41c). Within the mapped area and andesitic ashes, and Patua loam (65b) for of brown granular loams and yellow-brown loams soils derived from andesitic ashes. of districts south of Auckland to northern Raglan Karaka, Weymouth (66b), and other similar there are numerous small areas of red loams soils occurring around Manakau and Waitemata derived from outcrops of basaltic lava and scoria. harbours are included in yellow-brown loams. The latter soils are generally similar to Papakauri They are developed on sediments derived largely silt loam (77a, Chapter 11) and make excellent from volcanic ashes but in places partly from land for vegetables and field crops. Rangitoto and marine rocks. These soils have less friability and Motutapu Islands in the Hauraki Gulf are covered phosphorus fixation and greater potassium reten- with basaltic lava and ash last erupted about 300 tion than typical yellow-brown loams but resemble years ago. Rangitoto soils (96d) formed from the them more than yellow-brown earths, towards ash deposits are black to dark brown deep sandy which they grade with an increasing proportion loams that are rich in nutrients. They could be of materials from marine rocks. used for intensive cropping.

2. Central brown granular loams 3. Central and northern yellow-brown earths

Brown granular loams are extensive on rolling Yellow-brown earths and related steepland soils and easy hill country south of Auckland to the cover most of the ranges and hill country of South yellow-brown loam boundary through Hamilton. Auckland district. On this land thin deposits of They are derived from old deposits of andesitic volcanic ash have been mostly eroded away and and rhyolitic ashes (Hamilton ashes) either not the soils are formed from weathered sedimentary covered by later ash or exposed by erosion of the or rhyolitic rocks. These soils are less brown, less thin cover. (Brown granular clays and related friable, more sticky, and have weaker development yellow-brown steepland soils derived from andesitic rocks in of aggregates than the associated the northern end of Coromandel Peninsula are loams or brown granular loams. They differ widely described with the North Auckland region, p. 65.) in colour, texture, fertility, and other characteristics. greyish Topsoils are brown to brown friable silt They may conveniently be described according loams to clay loams and pass downward into to their general location on western coastal or brown to yellowish brown clay loams to clays. central ranges. On the western coastal ranges yellow- Aggregates are moderately to strongly developed from Mokau valley to Waikato Heads the granular to nutty in topsoil, grading to blocky in brown earths are greyish brown clay loams on subsoil. In the subsoil, aggregates are usually yellowish brown to yellow clay loams and clays. packed 50 tightly but separate easily. These soils are They have formed under an annual rainfall of sticky when wet owing to their high content of to 70 in, and a mixed broadleaved-podocarp

61 3-2 forest and resemble the yellow-brown earths of between yellow-brown sands and yellow-brown northern Gisborne more than those of North earths. Auckland. In general the soils are moderately 4. Central recent, gley, and organic soils leached and with phosphate topdressing will plains support good pastures for sheep and cattle breed- Flood and swamps are extensive in the Hauraki Plains in lower Waikato Valley. ing. Differences within the district are related and the Innumerable present in bottoms chiefly to parent materials and are illustrated by small areas are the draining hilly lands. three soils. Wairama soils (31c) derived from mud- of valleys the rolling and The derived from peat stones with limestone bands are moderately fertile soils are alluvium or on and generally stable except for occasional deep- low-lying land with the water table close to or at seated slumping. Mangatea soils (31c) derived the surface. Free-draining river flats are rare, drainage is first for productive from mudstones with sandstone bands are moder- and the requirement prone Two groups ately to highly fertile but are to severe slip use. of soils are separated-gley domin- erosion. Surfaces exposed by slipping are readily soils and organic soils-according to the in covered by vegetation. Marokopa soils (32a) ance of mineral or organic materials their derived from indurated mudstones and argillite composition. Gley have dark grey black loamy have moderate to low natural fertility but are soils to pale grey subject to shallow slips that recover slowly and topsoils over to white massive subsoils be few are liable to gullying. Each association has re- in which there may to many rusty mottles. Loamy lated steepland soils with similar properties. Textures range from sandy loams to clays. pumiceous include On central and eastern ranges around the soils derived from alluvium the periodically flooded Puniu (87b) Hauraki Plains and Firth of Thames the yellow- soils with the for brown earths are very strongly leached and in water table close to the surface most of the year, (87a) places weakly podzolised and are similar to the and the Waitoa soils with a widely Whangaripo (39a) and Waikare soils (39b) of fluctuating water table and only occasional alluvial peaty loams (87a) formed North Auckland. Topsoils are brownish grey to accumulation. Te Rapa peat pumiceous grey silt loams with weakly developed very soft from mixtures of with alluvium in group. granular aggregates. Subsoils are very firm yellow are also included this Loamy soils peat flood clays with coarse blocky aggregates combined interlayered with are common on the plain lower Waikato Valley illus- into large prisms. They were formed from deeply of the and are Hauraki weathered rocks under mixed podocarp-kauri trated by the Akeake soils (86a). In the heavy derived from forests and annual rainfalls of 50 to 70 in. The Plains, soils estuarine muds illustrated by Hauraki rocks are older, more siliceous, more weathered, are extensive and are clay (86a), profile is: and less eroded than the materials forming soils a of which on the western coastal ranges. The Opaheke soils 3 in, brownish grey clay; slightly sticky and plastic, hard dry; moderately developed medium (41a) formed from greywacke are underlain by when granular structure with fine reddish brown mottles period prior red-weathered materials of the to on surface of aggregates and along root channels; deposition of volcanic ashes. Maramarua and many roots but concentrated in cracks; indistinct Mangatawhiti soils (41c) derived from a highly 12 in. 1 bbr wnn grey clay with many fine strong siliceous variety of greywacke also show evidence brown mottles along root channels; plastic and developed medium of fossil soils, occurrence of which sticky; moderately to coarse truncated the blocky browrnsh grey coatings yellow-brown structure with to explains their marked difference from aggregates; few roots; indistinct wavy boundary, earths of the western coastal and central ranges. on pale grey plastic massive clay. Fertility is low, and heavy topdressing with These gley soils are moderately to slightly acid plant phosphates and lime is required to maintain and have a moderate to high content of pastures. Yields of timber from Maramarua soils nutrients. When drained they will grow excellent phosphate are considerably increased by and pastures, but the softness of the surface during grazing. nitrogen topdressing. and after rain creates serious problems in poached Along the western coast between the bare Paddocks become severely and open to sands of the beaches and the yellow-brown earths invasion by rushes, buttercup, and other weeds. gley is a discontinuous narrow strip of soils developed Best use is obtained by farming the soils in on old wind-blown sands. These Horea soils conjunction with drier soils, either yellow-brown (55b) are dark brown friable sandy loams over loams or steepland soils. brown firm sandy clay formed from sands derived Organic soils are formed from accumulations plant mainly from volcanic debris. They are slightly of partly decomposed remains under condi- ground The more weathered than Red Hill soils (55a and tions of continuously high water. b) of North Auckland and include intergrades range of soils is illustrated by Kaipaki loamy peat

62 3-2

(84a) formed on the edge of large peat swamps that differ according to soil process, parent from peat mixed with a little alluvium washed off material, and age. The yellow-brown earths and adjacent lands, and Rukuhia peat (84b) formed podzols contain montmorillonite, kaolin, clay- in the central part of raised peat bogs. The soils vermiculite or secondary silica, and the red and are formed from forest, manuka, fern, sedge, and brown loams contain allophane, gibbsite, goethite moss peats in various stages of humification. and kaolin. The extent of enleaching of the soils Generally the greater the proportion of mineral depends partly on the native vegetation. Mull- additions and the greater the humification the forming trees tend to maintain the level of cations richer the organic soil for agricultural uses. They in the topsoil whereas mor-forming trees lead to require careful drainage and management mainly their depletion. In contrast to the remainder of to control water, as once peat dries out thoroughly New Zealand most of the soils in this region are it becomes puffy and very difficult to moisten. Dry clays with thin topsoils, low subsoil fertility, and peat is also susceptible to fires, which leave a rapid decomposition of organic matter on aera- series of craters and irregular ridges that suffer tion. Sand-fraction analyses indicate that the extremes of soil moisture. Successful farming of soils have received accessions of volcanic ash these organic soils depends on levelling of the from both distant and local sources. The soils are field, applications of lime, phosphate, potash, mostly unsuitable for cropping, but with proper copper, and nitrogen, control of ground-water topdressing and management maintain productive level, and consolidation of the surface by stocking. pastures for dairying and sheep fattening; most of the soils need lime and phosphates and many need potash and trace elements. The optimum amounts of topdressing vary with the kind of NORTH AUCKLAND soil and hence a knowledge of the soils is essential (Region F, Fig. 3-1-3) in determining topdressing practice. The soils are North Auckland Peninsula stretches north-west a link between the temperate and tropic soils, and of Auckland city for 200 miles between latitudes broadly their farming problems lie in adapting 370S and 34oS. It is mainly low rolling and hilly them to the methods of farming evolved for the land with some steep land and high plateaus in lighter textured, better aerated, and quicker draining The the northern part, numerous small river flats in soils of the cooler temperate regions. discussed headings: the valleys, and extensive sand dunes along the soils are under eight western coast. This landscape is formed from a 1. Northern rendzinas; 2. Northern yellow- wide variety of rocks-greywacke, sandstones, brown earths; 3. Podzolised northern yellow-brown mudstones, limestones, rhyolites, andesites, basalt earths and podzols; 4. Northern brown granular flows, and their erosion products on flats and sand loams and clays; 5. Red and brown loams; 6. dunes. The climate is warm and humid. Mean Northern yellow-brown sands; 7. Northern recent, I annual temperature at sea level is 57 to 600F and gley, and organic soils; 8. Steepland soils. annual rainfall 50 to 100 in, well distributed 1. Northern throughout the year. Frosts are rare. The original rendzinas forest was mixed subtropical rainforest for the Rendzinas are heavy soils derived from calcar- most part, with considerable areas of manuka reous parent materials and occupy small areas near scrub on coastal lowlands and dunes. Mangroves Kaitaia, Kaikohe, and Maungaturoto. Their char- grew in the numerous tidal inlets along the coast. acteristics are illustrated by Arapohue clay (52a, In some places kauri was the dominant tree, but Chapter 11) and include notably the very high commonly the forest was a mosaic of kauri and cation-exchange capacity and base saturation and podocarps on ridgetops and upper slopes, and high content of well decomposed humus and of profiles broadleaved trees such as taraire on the lower montmorillonitic clay. In shallow the slopes and gullies. Certain fertile areas supported dark grey or black clay lies directly on limestone; broadleaved forest of taraire, puriri, and kohekohe, in deeper profiles the rendzinas occur with other with kahikatea on the wetter flats. The broadleaved soils in all stages of soil-horizon development trees were mull-forming and the podocarp and including yellow-brown earths and occasionally conifer trees were mor-forming (Chapter 7-2). podzols. Apparently, when the montmorillonitic general There is a strong correlation between the clays began to alter under the warm humid climate, composition of the native forest and the degree rapid profile changes (degradation) and drainage of soil development, and this is repeated in the deterioration accompanied changes of vegetation different groups of soils. from broadleaved to podocarp and later to conifer Under the warm moist climate the rocks weather (kauri) forest. With phosphate topdressing the rapidly and most soils have high clay contents rendzina soils make excellent pastoral land.

63 3-2

2. Northern yellow-brown earths stages but tend to be thicker on subsoil aggregates moderately strongly leached soils. Yellow-brown earths are extensive on rolling of to and hilly lands and form mostly from strongly 3. Podzolised northern yellow-brown earths weathered sedimentary rocks under dominantly and podzols mull-forming forest. They are heavy soils, greyish Podzolised northern yellow-brown earths and brown to grey clay loams in the topsoil and podzols are commonly found on easy sloping low yellowish brown compact clays in the subsoil. ridges or lower slopes of rolling land and are Other properties vary with the state of enleaching, developed from deeply weathered sedimentary which ranges from weak to strong. Mor-forming such as kauri, rimu, Weakly leached yellow-brown earths such as materials. trees and kamahi dominated original vegetation Puhoi clay (38a, Chapter 11) occupy small areas the accelerated enleaching process. Well of hilly land associated with Waiotira (38b) or and the developed podzols have grey with Whangaripo soils (39a). Weathering rock is usually thin topsoils little or no structure, overlying successive horizons found within 3 ft of the surface and shows no of pale grey, black, reddish brown, yellowish evidence of red weathering. Waiotira clay is an brown, and yellow colours. Available plant nutri- example of a moderately leached yellow-brown ents are mainly cyclic and are largely retained in earth, and a profile under pasture is: the mor horizon. On removal of trees the mor A 4 in, dark greyish brown clay; friable; moderately granular horizon oxidises expose a surface developed, medium to coarse rapidly to horizon of very low natural fertility. The grey brown B 12 in, n clay with reddish mottl- horizon black and brown developed subsurface and the ing;aTedb70firm to very firm; moderately horizons are into humus, coarse nutty to blocky structure with a subsoil cemented silica, prisms tend cy to coarse and thin coatings and iron pans respectively in downward order and in some sites pans are repeated at lower C on pale yellowish brown clay; firm; moderately these podzolisation. developed medium blocky structure; frag- depths indicating previous periods of meec The well developed podzols in North Auckland a abonudt 4 na llsandston kauri and kauri gum more numerous below. contain numerous stumps known ’gumlands’. Lenticu- Other moderately leached soils (and their res- and are commonly as podzols (egg-cup podzols) developed directly pective parent materials) are Taumata (38c, lar kauri in areas of yellow- calcareous sandstone and mudstone), Omanaia underneath old stumps brown indicate close association with (38a, banded sandstone and mudstone) and Omu earths their kauri (in 38b, mudstone). With light to moderate appli- the tree. Soils of podzolisation are included cations of phosphate and lime all these weakly of all stages group because frequently form a and moderately leached soils support excellent within this they detailed map for pastures for dairy cattle or sheep. mosaic that requires a very their Strongly leached yellow-brown earths are illus- separation. Waikare clay (42a) represents a moder- developed 11) ately podzolised yellow-brown earth on trated by Whangaripo clay (Chapter which (Chapter 11). Chemical, physical, and commonly occurs on parent materials that show claystone biological properties are intermediate between red weathering. Related soils (and their respective (39a) Wharekohe soils (47a). parent materials) are Marua (39d, greywacke), Whangaripo and Other podzolised soils and Rockvale and Dairy Flat (in 38d, calcareous weakly or moderately parent Rangiora-Opaheke mudstone and sandstones), Aponga (38b) and their materials are: greywacke), Okaka (39a, b, mudstones), and Warkworth (41a, greywacke, and red-weathered Mata (41b, mud- (39c, sandstone) soils. These soils are extensive on Tangitiki (42c, sandstone) and All are strongly acid and lower hill slopes and rolling land and are commonly stone). of these soils in because presence of associated with weakly podzolised yellow-brown low nutrients and of the blocky aggregates aeration and mois- earths. In contrast with less leached soils, they coarse their pale fluctuate widely. Clay films in have slower drainage, increased amounts of ture contents the in and have grey and brown mottlings in the subsoil, and subsoils are very uneven thickness podocarp-broadleaved rough surfaces. Pastures or exotic forests are their native vegetation was difficult soils and require forest with kauri. These differences are accom- to establish on these lime fertilisers. panied by increases in kaolinitic clay and in large amounts of and other Wharekohe silt loam (47a, Chapter 11) is a acidity, and decreases in base saturation and podzolised soil formed from banded levels of macro and micro plant nutrients (Chapter strongly It is strongly acid and 8). In a leaching sequence topsoils tend to become sandstones and mudstones. strongly leached, and has a deep kauri mor thinner and aggregates coarser, more blocky, and very horizon. Its structure and drainage are poor and more prismatic; clay films are common at all

64 3-2 its biological activity very low. Humus extracts but of lower natural fertility and require light pastures. Their general from the mor penetrate to a depth of 36 in, as topdressing to maintain illustrated by following shown by the high organic carbon in the subsoil. characteristics are the pasture: Marked increases in aluminium, iron, chromium, profile of Awapuku soil (74a) under friable; and gallium contents occur in the subsoil. Hukere- 4 in. dark greyish brown clay loam; moderately hwithra r an (47a) derived from sandstones and grey- nui soils 8 in. Id ott tu@ble but wacke and Pokapu soils from claystones (47b) compact; moderately developed fine blocky struc- are podzolised soils without distinct illuvial humus ture with thin clay skins, on hfr or iron accumulations but with a prominent clay 1 me tol bl bu m t;6 eay e B horizon. With moderate applications of lime fine blocky structure. dTrea and plant nutrients they maintain good pastures These weakly and moderately leached soils are for dairying or sheep farming, but light stocking slightly acid and high in exchangeable calcium pugging. in potassium in winter is essential to prevent surface and magnesium but low available Podzols formed on slightly consolidated sands are and phosphorus. They are commonly associated have Kie (76a) are included in the Te Kopuru soils (48a). They with the Te steepland soils and indurated silica, humus, and iron pans that cause farmed with them. wide fluctuations in moisture and consequently Strongly leached brown granular clays are limit plant growth and farming use. Similar limita- illustrated by Waimatenui clay (74b, Chapter 11). (74b) is formed tions also apply to the Ohia and One Tree Point Waitakere clay a similar soil soils (48b) developed on strongly podzolised sands from less deeply weathered andesite. These soils hilly land, previously with high ground-water level. Their very low occupy extensive areas of nutrient content together with the problems of in mixed podocarp-kauri forest and now mostly controlling ground-water levels, severely limit cleared for pastoral use. Where kauri became leached their productive use for farming or forestry. dominant the soils are very strongly as illustrated by Tutamoe clay (75b, Chapter 11), per 4. Northern brown granular clays and loams which occurs under high rainfall (100 in. plateau 2,000 ft in Brown granular clays are derived from andesitic annum) on a approaching Gleying in Tutamoe is responsible rocks and volcanic ash and are formed under altitude. the soils greater 50 in. for high carbon levels and low biological forest and an annual rainfall than the They are extensive on hilly land and rolling activity. granular developed kauri- plateaus at elevations from sea level to 2,000 ft Brown clays under North dominant forest at low elevations are illustrated and more, mainly on the western side of Auckland Peninsula. They are clay soils with by the Rangiuru-Aranga soils (75a). They are leached scrub and rushes greyish brown to brown friable topsoils on brown very strongly and manuka have largely forest. The to yellowish brown firm to compact subsoils and replaced the original developed granular have moderately to strongly developed granular topsoils have very strongly grading consequently hold little and nutty structures in the topsoil into and nutty structures and liable and are a blocky to prismatic structure in the subsoil. The moisture, are to sheet erosion, difficult for grasses and soils resemble the brown loams in having a high medium establishing dense heavy prismatic content of free iron oxides but differ in their clovers. Subsoils are clays blocky higher content of kaolin, absence of gibbsite, and that break into coarse aggregates with greater compaction and stickiness. Their consist- humus-stained surfaces. Heavy topdressing with properties phosphate, potash, lime, and elements is ence and many other vary with the trace pastures. When degree of leaching in a similar manner to the needed to establish and maintain pastures gradually be- yellow-brown earths. Fixation of phosphorus is are established, the soil greater in mellow and fluctuations of moisture less than in the brown loams but than comes more pastures yellow-brown earths and increases the phosphate become less. Dense are needed to control requirements for pasture development. The soils sheet erosion. Associated leached brown are commonly used for pastoral production and with the very strongly granular land are little used for forestry. clays on easy rolling are small podzo- Weakly leached brown granular clays such as areas of soils showing distinct evidence of lisation. Their grey structureless, Takitu soils (74a) occupy small areas, mainly topsoils are and brown heavy hilly land. They developed under broadleaved and their subsoils are clays with pans. Tinopai forest and, when cleared, carry pastures for many humus and iron They are the soils (75c), demonstrate of successive years without requiring to be topdressed. Moder- which the ability generations kauri forest produce podzolisa- ately leached brown granular clays formed under of to parent mixed broadleaved-podocarp forest are extensive tion on andesitic materials.

65

B 3*2

5. Red brown loams but production and obtained, is limited by the high The red and brown loams are formed from retention of phosphorus. basaltic rocks under subtropical forest and annual Strongly leached brown loams are developed rainfalls of 50 to 80 in. The group includes both under mull-forming mixed broadleaved-podocarp podocarp-dominant the red loams from scoria and scoriaceous rocks or forest. They include the and the brown loams from the denser rocks of free-draining Waiotu soils (78a) on rolling and basalt flows. Red loams are generally present with hilly slopes, and the related Ruatangata soils brown loams but in areas too small to map separ- (Chapter 11), which occupy flattish land and have ately. In both soils the rocks have weathered to their internal drainage impeded by the underlying clays of low plasticity that consist either of amorph- basalt. Both soils have low natural fertility for ous or crystalline oxides of aluminium and iron. pastoral purposes and require lime as well as Even where the clay content is high (50 o/o and phosphate for high pasture production. Similar more) the soils are so friable that the farmer soils at Kerikeri are used for horticulture, notably regards them as loams. To name them simply citrus orchards. as ’clays’ would be confusing to the farmer, and, Brown loams of very low fertility occur on plateaus consequently, in naming the soil units the term undulating to flat in the Bay of Islands ’friable clay’ is used to indicate their unusual district. They were formed under mixed podocarp- textural properties. Topsoils range in colour from kauri forest, later replaced in places by manuka red to brown, are very friable, and have a very scrub. They have friable granular topsoils only granular fine structure. Subsoils are also red to 6 in, thick, overlying tightly packed fine nutty brown and range from very friable to very firm and blocky aggregates with numerous small brown in consistence and from fine nutty to blocky in limonite concretions down to a depth of 16 in, structure. Drainage is generally good except in and more from the surface. The parent material some soils on flat basalt sheets, which induce is strongly weathered basalt, which is a poor ground-water temporarily high levels during and source of nutrient elements to the soils. Okaihau after heavy rain. The high content of sesquioxides friable clay (79a, Chapter 11) represents the soils causes high phosphate retention, which is a serious now in scrub, while those in kauri-podocarp forest handicap to high agricultural production; conse- are included in the Taraire soils (79a). They are quently the kind, time of application, and place- friable and easy to work but all are very low in plant ment of fertilisers are particularly important on nutrients and require heavy topdressing for these soils. pastoral use. Small areas have been developed for For purposes of classification, the red and dairy farming and sheep fattening. brown loams are arranged in soil-development 6. Northern yellow-brown sequences, like the yellow-brown earths and brown sands granular clays, according to state of enleaching. Yellow-brown sands extend in an almost continu- Characteristics of a weakly leached red loam are ous strip along the western coast of North Auck- shown by Papakauri clay loam (77a, Chapter 11) land, extend across the peninsula between Kaitaia derived from basaltic scoria and ash under mull- and North Cape, and occupy small inlets on the forming broadleaved forest. It is a highly fertile eastern coast. They are formed on sand dune physical, soil with excellent chemical, and moisture complexes with intervening plains that are more properties for biological activity and plant growth. peaty than in the Manawatu-Wellington region. phosphorus Total and inorganic is high but Their pattern of distribution is similar to that in because of the high content of allophane the the latter region in that the development of soil is low. These leached part availability weakly soils are horizons increases inland-but for the most found on the sloping sides of volcanic cones. the sands are more weathered, the subsoils are They growing are used for vegetables or for browner and more loamy, and the clay fractions dairying. contain kaolin and gibbsite derived from adjacent Moderately leached brown loams are illustrated more weathered soils. The increased clay content by Kiripaka clay loam (77a, Chapter 11), which improves retention of moisture, but summer is derived from scoriaceous basalt under mull- drought limits pasture growth. Free drainage, forming broadleaved forest. They have lower grazing however, allows at times when the heavier levels of cations and nitrogen than the Papakauri soils are liable to pugging. soils and at depths below 9 in. from the surface The yellow-brown sands near the coast include granular. are less friable and The subsoil contains Pinaki soils (54a), which have a surface horizon of gibbsite. When considerable amounts of top- 2-4 in. of humus-stained sand held together by a dressed with phosphate moderate to high yields mat of roots overlying unconsolidated brown sand. pastures of either vegetable crops or dairying are They require a dense cover of vegetation to prevent

66 3-3 wind erosion. Houhora soils (55a and b) have slow, the soils are clays with coarse structure; pale grey slightly more developed horizons; the surface their subsoils are with rusty mottlings periods. horizon is 4-6 in. of dark brown sand and overlies and they are waterlogged for considerable Wairua (86b), yellowish brown loamy sand that grades down- With some soils, such as clay the ward into yellow sand. Soils on dunes stabilised problems of obtaining adequate drainage are but for a longer period during which broadleaved difficult to overcome, with others, such as forest became established are included in the Red Kaipara clay (86b), good pastures for dairying Hill soils (55b). Their topsoils range from sandy have been obtained after drainage and topdressing. heating in loams to sandy clay loams and overlie slightly Owing to slower of these soils spring grading in pasture growth is to moderately compact sandy clay loams and slower cooling autumn, downward into sand. With regular topdressings later but continues longer through summer and places of phosphate and potash the Houhora and Red autumn than on adjacent drier land. In is permanently high, peat Hill soils hold excellent pastures, which are used where the water table for fattening and dairying. They need little or no has formed. Soils such as Ruakaka peaty sandy peat in de- lime. With topdressing, moderate pastures can be loam and loamy (84a) are common maintained on Pinaki soils, which are also used pressions among sand dunes, and when carefully in part for forestry. drained and topdressed carry valuable summer pastures for dairying. These pastures require 7. Northern recent, gley, and organic soils topdressing with phosphate, potash, and lime, plains of copper offset a high In North Auckland the soils on flood and small amounts to and swamp lands are small in area and isolated, molybdenum content. but owing to their above-average fertility and 8. Steepland soils their suitability for mechanical improvement they provide very valuable agricultural land. They are Steeplands in North Auckland consist of isolated derived from either alluvium or peat, and their ranges where hard rocks have resisted erosion. The derived from major differences are related to the conditions of soils are either andesitic rocks greywacke accumulation. (Te Kie, 76a) or (Te Ranga, 40a) and On the narrow strips of free-draining flats have thin topsoils subject to rapid sheet and slip pastoral Their general bordering rivers and streams the soils are deep and erosion under use. other properties illustrated by Te Kie loamy and need little or no fertiliser to become are the steepland for highly productive. They are too small in area to soils (Chapter 11). They are excellent soils show separately on other than detailed maps. forestry and under this use water resources are On the wider flood plains, where drainage is more adequately controlled.

3-3- SORS OF SOUTH ISLAND

by J. D. RAESIDE, C. G. VUCETICH, J. E. Cox, J. D. McCRAW, M. L. LEAMY, E. J. B. CUTLER, and H. S. Glass

NORTH-EASTERN REGION, graphic units and of rock formations across the SOUTH ISLAND region is as follows: (RegionG,Fig.3-1*3) 1.The Nelson lowland between ranges of granite, gabbro, and limestone on western The north-eastern region of the South Island the and of greywacke, sandstone, argillite, and comprises the Sounds district, the central and side on eastern side. The eastern ranges eastern parts of Nelson, and lowland parts of schist the interbedded strips of basaltic and ultra- Marlborough and north Canterbury. It is a contain basic rocks and northern end of ranges region of strong contrasts, with small areas of the the has been depressed form Marlborough rolling lowlands and alluvial plains alternating to the Sounds. The lowlands consist of dissected con- with high steep ridges extending across the country. glomerate beds known Moutere Gravels, This pattern is due primarily to the geological as the alluvial and plains along Motueka structure which consists of long earth blocks with terraces the Waimea separated by a series of north-east-trending fault and rivers. lines along which considerable vertical and hori- 2. The Wairau valley of alluvial terraces and plains hilly land zontal movements took place during the late with a fringe of rolling and Tertiary and Pleistocene. The succession of topo- formed on weakly consolidated sandstones and

67 conglomerate over which a shallow coating of between 30 and 45 in., and the native vegetation loess has been deposited. It is bounded on the was mixed scrub and tussock grasses. The basins east by greywacke ranges. themselves have annual rainfalls between 25 and 3. The Awatere Cape Campbell Clarence low- 35 in, and originally had native tussock grassland

- - and scrub. The grasslands and scrubland were land consisting of rolling to hilly land formed on burned during Maori but weakly consolidated beds of siltstones, sandstone, many times occupation, in grazing conglomerate, and limestone with a discontinuous the absence of animals they were by little and shallow coating of loess. This lowland passes covered again similar vegetation with apparent soil loss by erosion. Grazing and cultiva- abruptly inland into the steep, greywacke slopes practices introduced after European settle- of the Kaikoura Ranges. Narrow strips of terraces tron ment have now converted most of native grass and flood plains are present along the Awatere, the pastoral grasses fodder Blind, Flaxbourne, Kekerengu and Clarence rivers. and shrubland to and some Soil formerly serious, is gener- The lowlands are separated from those further crops. erosion, now by Since south by the Puhipuhi Ranges formed from grey- ally controlled suitable management. European large forest have wacke, sandstone, and limestone. settlement areas of been cleared and sown to grassland. Some re- 4. The Kaikoura lowland consisting of stony placement of forest by grassland has been suc- fans built by streams flowing from coastal the cessful, but in many places, especially those slopes of the Seaward Kaikoura Mountains. previously in beech forest, the grassland has been 5. The Cheviot, Culverden, and Waipara basins slow to establish. In these areas the topsoil has Canterbury, of north which are surrounded by been reduced by sheet erosion, and manuka, hard greywacke by ranges and occupied extensive fern, and shrubs have invaded the pastures. Some downlands of weakly consolidated sediments cov- of these unsuccessful pastoral farms have been ered with deep loess and by narrow strips of planted with exotic trees, which are thriving and alluvial plains Waiau, terraces and along the providing additional industry for the region. Hurunui, Waipara and rivers. Fruit, tobacco and hop-growing industries have The contrast in topography and rock forma- also been established on the coastal lowlands near tions is also seen in the pattern of climate and Nelson and fruit and seed-growing industries on vegetation. Mild humid climates with annual similar land near Blenheim. groups rainfalls of more than 45 in. prevail over most of Six of soils are separated: 1. Central yellow-grey 2. the Nelson and Sounds districts, and the original earths and related steepland soils; vegetation was mainly beech forest with podocarp- Central yellow-brown earths and related steepland podzols broadleaved trees in some coastal valleys. A soils; 3. Central and southern and related 4. Central narrow strip around the coast from Motueka to steepland soils; rendzinas and related brown granular Nelson, with an annual rainfall of 35 to 45 in., steepland soils; 5. Central clays was covered in manuka scrub and fern at the time and related steepland soils; 6. Central recent and of European settlement. The native forest stopped associated gley, organic, and saline soils. abruptly on the north-western side of the Wairau 1. Central yellow-grey valley, and the lowlands of Wairau, Awatere, earths and related Cape Campbell, and Clarence districts were steepland soils clothed in native grasses. Annual rainfalls Yellow-grey earths are extensive in Awatere tussock the - of these lowlands are between 25 and 35 in, and Cape Campbell Clarence lowlands and in the - their effectiveness is reduced by their irregular basins of north Canterbury. They are represented distribution throughout the year and by frequent by the Ngapara, Glendhu, Waipara, Sedgemere, drying winds. Inland near the mountains the associated Lismore, and related Haldon soils patches rainfalls increase from 35 to 45 in., and developed under short tussock grassland and a of manuka scrub now grow amongst the tussock mild subhumid climate with an annual rainfall grassland. South of the Clarence River the native between 20 and 35 in. With increasing rainfall grade vegetation changed abruptly again to broadleaved- and decreasing temperatures they into podocarp forest on the Puhipuhi Ranges. In the yellow-brown earths. Intergrades between the same area annual rainfalls are up to 80 in, in two groups are described with the yellow-grey places. This forest continued across the alluvial earths. These intergrades, named Leader, Medina, fans of the Kaikoura lowland but changed to Kekerengu, Hundalee, and Mapua soils, are beech forests on the steep ranges further south mainly on foothills to the lowlands and on a in the Kahutara valley. Here the annual rainfall coastal strip around Tasman Bay. They are is between 45 and 50 in. Further south around the developed under a mixed tussock and scrub vegeta- north Canterbury basins annual rainfalls are tion and annual rainfalls between 35 and 45 in.

68 3-3

On all of the soils in this group the rainfall is rainfall of 25 to 35 in. Profiles consist of 5 to 8 in. unevenly distributed throughout the year causing dark greyish brown stony silt loam on brownish droughty periods that limit pastoral use and forest- yellow very stony silt loam and shattered grey- ry. wacke. They are used for extensive sheep grazing Ngapara soils (4b) are mapped in the Seddon - and show few signs of soil erosion. Cape Campbell district on hilly to rolling land Leader soils (15a) and Medina soils (15b) are covered with recent accumulations of loess. Their found in the Kaikoura, Conway, Waiau, and profiles consist of about 12 in. greyish brown Motunau districts under annual rainfalls of about granular silt loam over yellow coarsely blocky 40 in.-Leader soils on hilly land and derived and compact silt loam. They are weakly leached from sandstones, Medina soils on rolling to un- soils of moderate to high fertility used for mixed dulating land and derived from silty sediments. cropping and pastoral farming. The soils are liable Their profiles have dark grey nutty silt loams to be depleted by sheet erosion, chiefly during or olive brown and grey mottled clay loams with cropping. a coarse blocky structure. Natural fertility is low Glendhu soils (7a) developed on sandstones or to moderate, but the soils maintain excellent pastures conglomerate are extensive on the hilly to rolling after phosphate topdressing and over- land of the Clarence, Cheviot, and Waipara dis- sowing. Drainage of the Medina soils is slow and tricts. Topsoils are grey silt loams (or stony silt tile or mole drains are required for heavy stocking. loams) with a weak granular structure grading Kekerengu and Hundalee soils (16b) are mainly down into compact yellow silt loams (or stony on hilly land in the Awatere and Clarence low- loams) pale grey silt with mottling. The soils are lands under annual rainfalls of 35 to 45 in. Keke- weakly to moderately leached and are used for rengu soils are developed from argillites, and their sheep breeding. Good responses are obtained by profiles have dark grey granular silt loams on oversowing pastures with clovers and phosphate. yellow compact gravelly clay loams. Except on fair quality pastures Waipara and Sedgemere soils (8b) cover a dry ridges, these soils support phos- large area of loess-covered terrace, rolling, and that may be improved by oversowing and hilly lands in the Awatere, Cape Campbell, and phate topdressing. Slip and gully erosion are north Canterbury districts. These soils developed serious in some areas. Hundalee soils are developed profiles greyish under silver tussock and an annual rainfall of on conglomerates, and their have yellow 20 to 30 in, and have topsoils of greyish brown brown stony silt loams over compact stony granular silt loams on pale olive compact strongly silt loams. Owing to their low fertility, rapid mottled clay loams with a coarse blocky structure. drainage, and hilly slopes, they are of limited Moderately fertile Waipara soils cover rolling value for pastoral production. With oversowing, to hilly land and are susceptible to sheet and topdressing, and management with other soils, pastures quality. tunnel-gully erosion as well as severe droughts. they will maintain of moderate Methods of using these soils and of controlling Mapua soils (18a) are developed from weathered the erosion are demonstrated on the Wither Hills greywacke conglomerates on rolling and hilly Conservation Reserve, Blenheim. Sedgemere soils, land bordering Tasman Bay under annual rain- on flattish to undulating slopes, are used for mixed falls of 35 to 40 in. Their topsoils are thin dark crop and sheep farming with little risk of erosion. grey weakly structured sandy loams, and subsoils Lismore soils (9a) are shallow and stony soils are strongly mottled clay 10ams with coarse pris- occurring extensively on terraces in the Wairau matic structure. They are strongly leached soils valley and Culverden basin and in smaller areas of low natural fertility, and the topsoils are sheet along most rivers of central Marlborough and eroded in many places. Drainage is slow, and north Canterbury. They are greyish brown friable topsoils are overwet in winter but dry out exces- silt loams over gravels with a yellowish brown sively in summer. The wide variation in moisture silty matrix. A detailed description of Lismore silt in the topsoil is a handicap to pastoral farming loam is given in Chapter 11. The soils are droughty but pastures of moderate quality can be main- and of low natural fertility. They need irrigation tained by heavy topdressing and careful grazing and fertilisers to become good pastoral or cropping management. Moisture variations in the subsoil land. are smaller, and deep-rooting crops, fruit trees, Haldon soils (10a) are formed on steep grey- and forests grow well. For fruit trees and crops phosphorus, wacke country between the Wairau and Awatere regular treatment with nitrogen, and potash valleys and around the dry basins of north Canter- are needed, as are occasional light dressings bury. Mapped areas include Waihopai steepland of magnesium and boron. soils derived from greywacke conglomerate. These Ruapuna soils (19b) represent the shallow and soils developed under silver tussock and an annual stony soils on small areas of terrace land near

69 3-3

Richmond in Nelson and Hillersden in the Wairau and modern pasture management. Slip erosion valley. They are of medium to low natural fertility, could be controlled by spaced tree planting, and pastures require irrigation and top-dressing. Arahura soils (28a) and Ahaura soils (28b) are developed in the Tophouse-Rotoiti district on 2. Central yellow-brown earths and related thick gravel beds under beech forest and an steepland soils annual rainfall of 60 to 80 in. They are shallow Yellow-brown earths are widespread on the brown silt loams on yellowish brown stony sub- patches Nelson and Kaikoura lowlands and on the moist soils with of subsurface bleaching caused hills of the Wairau, Awatere, Clarence, Conway, by incipient podzolisation. Fertility is low and probably Waiau, and Hurunui valleys. Only a few areas the hilly Arahura soils are best used for of rolling land are shown on the soil map but forestry. With topdressing, Ahaura soils on ter- many more are included in the extensive areas of race and rolling lands make good pastoral land. hilly and steep lands. These soils developed under Whangamoa and Patutu soils (30a) are found beech, podocarp, or broadleaved forest under a on the steep eastern hills of Nelson and the Puhi- mild humid climate with annual rainfalls between puhi ranges north of Kaikoura under annual 45 and 60 in. The rainfall is fairly evenly dis- rainfalls of 45 to 60 in. They are formed on grey- tributed and subsoils are always moist. Topsoils wacke, argillite, and subschists under broadleaved- are greyish brown to brown, friable, nutty silt podocarp forest near the coast and beech forest loams over yellowish brown to yellow, firm, inland. Topsoils are greyish brown friable nutty blocky clay loams. The yellow-brown earths of silt loams, and subsoils are yellowish brown the north-eastern region comprise the Spooner, nutty stony silt loams. Most of the forest has been Rosedale, Tadmor, Arahura, and Ahaura soils cleared and coastal areas are being successfully and the associated Whangamoa, Patutu, Hurunui, maintained in pasture, but inland the country has Opouri, and Kenepuru steepland soils. The soils mainly reverted to manuka and fern. Exotic forests on the lower lands are more weathered than the have been established on Whangamoa soils near yellow-brown southern earths in the southern Nelson. region and are better grouped with the central Hurunui soils (30b) are very extensive on the yellow-brown earths of the North Island. steep greywacke country of the Wairau, Awatere, Spooner-Rosedale soils (29b) are extensive on and Kaikoura districts, which receive between the strongly rolling to hilly land of the Nelson 35 and 45 in. of rainfall annually. They lie be- lowland and in a small area of similar land in tween the Haldon and Patutu soils, and their the Waiau district of north Canterbury. The soils native vegetation was a mixture of hard and are derived chiefly from weathered conglomerate silver tussock on the drier sites and manuka, fern, of greywacke, granite, and basalt materials (Mou- and beech forest on the wetter ones. A common tere Gravels) under beech forest and an annual profile shows 6 to 8 in. dark grey stony silt loam rainfall between 45 and 60 in. Spooner soils have with nutty structure on brownish yellow stony a general profile of greyish brown nutty silt silt loam grading into weathering greywacke. The loam on yellowish brown heavy silt loam with soils have a moderate natural fertility, are slow stones. They are strongly leached soils of low to erode, and with aerial oversowing and top- natural fertility and are widely used for exotic dressing make excellent pastoral land for sheep forests. The mapped area includes sandy soils farming. derived from granite and having similar character- Opouri-Kenepuru soils (30c), on steep slopes istics and uses. Rosedale soils have a clay loam of the Marlborough Sounds and D’Urville Island, subsoil with slight mottling and grade into Mapua are formed from hard siliceous sandstones, argill- soils. They are nearer the coast than Spooner ites, and subschist, under annual rainfalls of 50 soils, have a slightly lower annual rainfall, and to 80 in, and beech-podocarp forest. The soils are widely used for pastoral farming after applica- are thin greyish brown nutty silt loams over tion of lime, phosphate, and molybdenum. yellowish brown silty clay loam. Owing to the general Tadmor soils (29c), in the upper Motueka low natural fertility, the absence of adjacent valley on hilly to steep land, are derived from flattish land, and to rapidity of sheet erosion, the mudstone and sandstone. They have greyish brown soils maintain pastures with difficulty and the friable and nutty topsoils on yellowish brown, large areas are better used for forestry. firm, nutty to blocky subsoils with textures vary- 3. Central podzols ing from sandy loams to clay loams according to and southern and related the parent rock. Most of the area of these soils steepland soils is in forest or in fern and scrub but could be used In the north-eastern region areas of podzols on for pastoral land with the aid of aerial topdressing rolling land are numerous but small and are

70 3-3

included in the Lewis steepland soils. They have the lower slopes has been largely replaced by a dark brown organic horizon over successive grassland for extensive grazing. thin dark grey, pale grey, and brown to yellowish 5. Central brown granular loams brown horizons, are strongly acid, and are low and in mineral nutrients. The pale grey horizon is related steepland soils very irregular in thickness but is most prominent Brown granular loams are formed on the basic under silver beech trees. The soils have very low and ultrabasic volcanic rocks that crop out ex- natural fertility and require large applications of tensively on the hills surrounding the Nelson fertilisers to maintain pasture. With the adjacent lowland and to a smaller extent in north Canter- Lewis steepland soils (45a) they are best retained bury. in native protection forest. The Lewis soils are Atawhai and Brooklyn soils (70b) are derived extensive on the steep greywacke and granite from massive intrusions of basaltic materials into ranges on each side of the Nelson lowland. Annual sedimentary rocks and consequently have complex rainfalls are 60 to 100 in., and the soils erode parent materials. Atawhai soils, developed under rapidly if the forest is cleared. Areas in tussock broadleaved forest and an annual rainfall of 40 and herbfield above the forest line included in to 50 in., have greyish brown granular to nutty the Lewis soils, also contain Spenser soils (see silt loam topsoils on reddish brown to brown, p. 78). firm, blocky clay loam subsoils. Brooklyn soils formed under podocarp-beech forest and an 4. Central rendzinas and related steepland soils annual rainfall of 50 to 60 in, and are more brown in yellow in Rendzinas and related rendzic soils are formed the topsoil, more the subsoil, and Atawhai on the limestone and calcareous rocks that crop more variable in texture than the soils. Both fertility out in many areas of the north-eastern region. soils are of moderate and with fertilisers hold pastures well, although pasture Only three areas are large enough to show on production Atawhai is by the accompanying map, but their differences on the soils restricted droughts. Considerable of illustrate the chief properties of the group. seasonal areas these gorse. Heslington soils (50a) occupy a long narrow soils are covered with manuka, fern, and Waiareka (67a) as mapped on hilly land strip of hilly and steep country along the eastern soils in profile side of the Nelson lowland. They are developed in the Waiau district are similar and general properties Atawhai under annual rainfalls of 35 to 40 in, and a mixed to soils except that grey broadleaved-beech forest. Their profiles have top- their topsoils are dark and nutrient levels higher. With soils 9 to 12 in, thick with dark greyish brown are light topdressing and oversowing hold good pastures. granular to nutty silt loams on olive brown silt they loams with many fragments of calcareous sand- Dun soils (71a) are developed on ultrabasic stone and shale. These fragments are fewer in dunite and serpentine rocks under annual rainfalls 45 60 in, a low vegetation. They the related soils of the moderately steep and of to and scrub parts rolling slopes. Heslington soils are highly fertile occur on steep to moderately steep slopes of D’Urville Island, hills Nelson and are used for growing vegetables or for sheep of the eastern of district, Hills Range breeding. The strip of soils numbered 50a on and the Red of the upper Wairau Topsoils are greyish brown friable the map in the Waikari district of north Canter- valley. yellow- bury is developed from limestone under annual sandy loams or silt loams and subsoils are ish brown greenish brown, friable, stony clay rainfalls of 25 to 35 in, and under silver-tussock to low fertility grassland. It is mainly steepland with profiles of loams. They are soils of very with a black deep granular clay loams over weathering very high content of magnesium, chromium, and but low phosphorus, limestone. Brown clay subsoils of 1 to 12 in. nickel very calcium, and potassium. present knowledge Dun depth are common. These soils are also highly On soils are forestry. fertile but dry out severely and crack deeply. unsuitable for agriculture or They are used for extensive grazing. Similar soils 6. Central gley, occur near Cape Campbell in Marlborough. recent soils and associated organic, and saline soils Kaitoa soils (51a) are formed from limestone gley, and calcareous sandstone on steep land in the Recent, organic, and saline soils, on the Clarence-Kaikoura districts under annual rainfalls low-lying flat lands of valley bottoms, are derived have of 40 to 60 in. Topsoils are dark brown blocky from alluvium and organic materials that gains clay loams, and subsoils are yellowish brown clay accumulated recently. The losses and of loam to clay with many rock fragments. The soil formation have had insufficient time to make principal differences native beech forest remains on most of the higher large changes, so the soil are These factors slopes, but the broadleaved-podocarp forest on due to parent materials or drainage.

71 3-3 change frequently and on the accompanying map Tasman Sea for about 500 miles. The eastern side only the most extensive of the soils can be shown; is bounded by the crest of the Southern Alps in the north-eastern region the small proportion of rising to between 5,000 and 12,000 ft and includ- low-lying flat land permits only three units to be ing many icefields and glaciers. These mountains separated, all belonging to the recent group. consist of Mesozoic schist and greywacke which Gley, organic, and saline soils occupy only small end abruptly along a major crustal fracture called areas but their distribution is shown on detailed the Alpine Fault. The fault is marked by a line maps. Similar soils are described in the eastern of steep bluffs extending diagonally across the region section and in more detail in Chapter 11. region from the coast at Milford Sound to the Selwyn-Waimakariri soils (90a) represent the junction of the Nelson and Marlborough districts soils formed on freely draining parts of low flood- near Lake Rotoiti. West of the fault and north of plains in the Motueka, Waimea, Wairau, Kowhai, Greymouth are other mountain ranges formed on and Waiau valleys. They are greyish brown friable Tertiary sandstones and limestones, Palaeozoic soils, ranging in texture from silt loam to sand, granites and gneiss, and Precambrian greywackes. and overlying gravels. Selwyn sandy loam is Lowlands are very limited especially in coastal described in Chapter II. Where the gravels are regions north of Greymouth where high ranges places. close to or at the surface the soils are very droughty extend to the coast in many Narrow fringes and of low fertility, but, with an increasing depth of sand and alluvial terraces occur in a few bays of fine textured material, there is an increase in as well as inland along the rivers in the Takaka, moisture retention and in fertility. The deep fine Aorere, and Buller valleys. Terraces are more sandy loams and silt loams are the most fertile extensive along inland parts of the Grey, Inanga- soils of the region and are extensively used for hua, Maruia, and Murchison valleys which coincide vegetables, orchards, cereal, and fodder crops and with faulted depressions. South from Greymouth, for pastures for fattening sheep and cattle. In where the Alpine Fault is close to the coast, the humid region near Kaikoura the soils are lowlands are more extensive. They consist of used mainly for dairying. river flats, swamps, and terraces in structural Templeton-Eyre soils (91a) occupy well drained basins near the fault and in river valleys between plains parts of alluvial that are now rarely if hilly ridges of Tertiary sediments and Pleistocene ever flooded but receive small additions of moraines that extend out to the coast. loess. They are extensive in the north Canterbury The climate of the western region is humid to basins and developed under a subhumid climate superhumid, with mild temperatures at elevations with an annual rainfall of 25 to 35 in, and a below 1,000 ft. Annual rainfalls range from 60 in. native tussock vegetation. Texture ranges from at Golden Bay in the north to 100 in, at Grey- greyish general, sandy loams to silt loams, and topsoils are mouth and 200 in, at Jackson Bay. In brown and friable and grade into brownish yellow rainfall increases from the coast towards the compact subsoils resting on gravels. A detailed axial range; Denniston on the coastal range near description of Templeton silt loam is given in Westport receives 200 in., and farther south more Chapter 11. Where the soils are shallow they are than 300 in, is estimated to fall on the mountains very droughty, but elsewhere dry out slowly and above the bush line. On the other hand parts of are widely used for mixed cropping and pastoral the Grey and Buller valleys have lower rainfalls farming. (60 to 80 in.) and greater temperature extremes. Taitapu soils (92a) include the slow-draining The natural vegetation below about 3,000 ft is parts flood plains in of either basins behind the forest; in central Westland, from the Taramakau river levees or along the base of the hills. Small to a little north of the Paringa river, forests are present areas are in all valleys of the north-eastern podocarp-broadleaved; elsewhere they are mostly region and are recognised by the blocky subsoils mixed beech and beech-podocarp, with a coastal coloured pale grey or bluish grey with distinct strip of broadleaved and podocarp-broadleaved rusty brown mottles. A detailed description of forests. Swampy soils of low terraces carry ka- Taitapu silt loam is given in Chapter 11. The hikatea forest, raupo, rushes, and sedges, whereas soils are of high natural fertility, and with drainage high terraces support sedges, rushes, ferns, and are capable of intensive use for mixed cropping some silver pine forest. Forest on much of the pastoral farming for dairying. and or very wet terrace land has been destroyed by milling or fire, and these areas have deteriorated to WESTERN REGION, SOUTH ISLAND ’pakihi’ wastelands of umbrella fern, manuka, (Region H, Fig. 3 1 3) Other deforested hilly land - - rushes, and sedges. The western region is a narrow strip of mainly carries bracken fern and manuka. Above 3,000 ft mountainous land bordering Golden Bay and the the vegetation changes from forest through sub-

72 3-3

pan, horizontally is alpine scrub to alpme tussock grasslands and tree roots branch and there herbfields, thinning out until the alpine barrens a horizon of humus accumulation just above the gravels are reached at 6,000 ft. pan. The silty horizons overlying the in, 6 ft The soils of the western region are described range from less than 12 to more than under six headings: thick, and the gley horizon in some profiles is 2 ft Under forest cover, water 1. Central and southern podzols and associated more than thick. drains laterally litter and At horizon, soils; 2. Central and southern yellow-brown earths; through the but destruction forest litter 3. Central and southern yellow-brown sands; 4. of the after milling lateral drainage and surface aeration. The Central and southern organic soils; 5. Central and reduces is ’pakihi’ moss, southern recent soils; 6. Southern and central result a vegetation of sphagnum fern. On near steepland soils. rushes, and umbrella some terraces Westport, gravels are within 6 to 12 in. of the 1. Central and southern podzols and surface and contain numerous iron pans. associated soils On moraines and outwash gravel terraces there pattern Under podocarp forest and high rainfall most is an intricate of Okarito soils (A-gleyed podic flattish surfaces and Waiuta of the soils are strongly leached and have the soils, etc.) on (podic undulating sur- thick surface horizons of mor humus, subsurface soils soils) on to rolling greyish bleaching, and subsoil accumulations of iron and faces. Waiuta soils have thin topsoils of loam As horizons pale humus that are characteristic of podzolisation. brown sandy with of gleying brown loam, on iron pan Features due to are also widespread, and sandy resting a thin yellowish brown loam. Most it is difficult to separate the two processes except over sandy clay in soils developed on coastal sands. On soils attempts to farm areas of deforested Okarito failed, derived from sandy sediments the gleying probably soils have and such areas are now virtually being began after the formation of the iron pans by wastelands. Forests are now strip-felled, as With Waiuta podzolisation, but in the deep fine-textured ma- this assists regeneration. topdressing, grassland. Otherwise be terials, notably from schist, gleying probably soils maintain they may forests. accompanied podzolisation from the beginning used for exotic (44b) between 1,500 and accelerated the eluviation of iron. Differences Denniston soils occur to 3,000 ft within the group are illustrated by the Onahau- on siliceous sandstones and mudstones, Kotinga, Tautuku-Hinahina, Okarito-Waiuta, and quartzites, and granites of the windswept easy Denniston soils. crests of hills near Westport and of the Gouland Onahau-Kotinga soils (43c) are formed on Downs in north-west Nelson. They develop under 200 in, terraces of greywacke and granite alluvium in rainfalls of 80 to and a natural vegetation herbs, podocarp north-west Nelson under rainfalls of 60 to 130in. of stunted scrub, and sedges, with land. Onahau soils are moderately podzolised and forest on some of the moderately steep gleyed, whereas Kotinga soils are only weakly so. Topsoils are thin greyish brown sandy loams with pale Both soils have a raw humus organic horizon very weak crumb structures, and subsoils are fragments over dark grey and pale brown to white sand. An brown sandy loams with rock and iron pan 1 to 2 in, thick underlies the As horizon rest on iron-stained rock. Under forest and scrub have iron pan, and is usually located in the fine sediments above the soils a thin cemented with in These the gravels. With heavy applications of fertilisers humus-filled fissures the underlying rock. poorly drained, intensely leached, small areas of these soils have been used for soils are very have low fertility. farming, but the slow drainage of the flatter areas and very natural is a serious limiting factor. 2. Central and southern yellow-brown earths Podzolised and weakly gleyed soils are developed on moderately steep land derived from sand- Yellow-brown earths are developed on some hilly parts stones west of Golden Bay, and near the coast close terrace and of the western region podzolisation because to the Buller and Grey rivers. They are included where there has been no with the Tautuku and Hinahina soils (43a), which of the formation of mull instead of mor humus. are described with the southern region (p. 85). The soils are Ahaura or Arahura soils derived gravels The soils on most terraces from Westport from with sufficient drainage to allow southwards are intensely leached gley podzols aerobic decomposition of the surface organic developed under kamahi, rimu, and silver pine matter, or Tadmor soils derived from mudstones forests. They are represented by the Okarito soils containing sufficient calcium and magnesium to (Chapter 11) in which strongly gleyed, massive, resist leaching and increase in soil acidity. very slowly permeable silty horizons rest on gravels Ahaura soils (28b) occupy beech-forested inter- granite cemented with iron oxide. On reaching the iron mediate terraces of greywacke, schist, and

73 3*3 alluvium in the Grey and Buller valleys, under free-draining alluvium of greywacke, granite, and gravels. 60 to 80 in. of rainfall. They are strongly leached schist, overlying Hokitika soils occur greyish brown nutty silt loams, on yellowish under podocarp forest (matai-totara) on flood brown stony or bouldery silt loams, with no plains that are occasionally flooded. Their topsoils cementing of the underlying gravels. The soils are are grey nutty fine sandy loams, and their subsoils highly regarded because of their free drainage, of grey fine sand rest on porous gravels. Ikamatua and when fertilised and well managed they carry soils, on terraces and fans under podocarp-rimu excellent pastures. forest, are dark greyish brown nutty fine sandy Arahura soils (28a) are also found on moderately loams on pale yellowish brown blocky fine sandy steep slopes of mixed greywacke, schist, and loams over gravels. Both soils are of moderate to granite gravels with some sandstones and limestone low fertility but are highly valued as farming land outcrops. They developed under podocarp-broad- because of their free drainage. leaved forest and have profiles of brown granular Harihari-Karangarua soils (92b) are imperfectly stony silt loams. Mapped areas include Blackball to poorly drained gley-recent soils. They are soils formed under beech forest and occupy developed from alluvium of schist, greywacke, pockets on ridges. These have thin pale brown and granite origin at some distance from river A2 horizons and thin patchy accumulations of channels under a swamp vegetation of flax, iron and humus in the B horizons. Arahura soils rushes, sedges and some forest. They are shallow in the Grey valley have been cleared of forest and brown fine sandy loams (with pockets of peaty are covered in manuka scrub and bracken fern. loam) on pale grey, blue, and reddish brown They are of low fertility and in many places are mottled fine sands. Harihari and Karangarua sheet eroded, but they are suitable for exotic soils are moderately fertile and where adequately forest. South of Hokitika most areas remain in drained are used for dairying. forest. 6. Near Greymouth moderately leached yellow- Southern and central steepland soils brown earths developed on calcareous mudstone Steepland soils occupy more than 80% of the are mapped with Tadmor soils (29c), which are western region. They receive high rainfall, and described with the north-eastern region where except for small areas derived from calcareous podzolisa- they are more extensive. materials most of them show signs of tion. 3. Central yellow-brown and southern sands Steepland podzols and podzolised yellow-brown Mahinapua soils (53b) occupy a discontinuous earths mapped as Otira-Wakamarama soils (45b) coastal strip of weakly weathered sands derived are extensive on steep to very steep slopes from greywacke, granite, from and schist. They de- the coast inland to the axial ranges, from sea veloped under broadleaved coastal forest, with level to 3,000 to 4,000 ft under rainfalls of 80 to grey- swamp forest in the hollows. They are dark brown 200 in. Otira soils derived from schist and loamy sands on friable yellowish brown loamy wacke support mainly rata-kamahi-rimu forest sands, have moderate fertility, and are intensively grading upwards into subalpine scrub. Under a farmed in places. Included are small areas of thin fibrous litter, soils are characterised by shallow Ikamatua soils on fans between the coastal hills dark brown sandy loam topsoils, very shallow and the sands. grey sandy loam A2 horizon with rock fragments, and yellowish brown blocky stony loam B horizons 4. Central and southern organic soils resting on schist. These soils are subject to sheet Kini soils (81b), in swampy depressions on and slip erosion on very steep slopes where the terraces above the level of river flooding, are very forest cover has been weakened by heavy browsing deer. acid peats developed from sedges, rushes, and of rata trees by introduced opossums and ferns and in places podocarp-swamp forest. Pro- Wakamarama soils are developed on greywackes, files consist of dark brown loamy peats on dark granites, sandstones, and conglomerates under brown semi-fibrous peats containing logs and beech-podocarp (rimu) on lower slopes, and under stumps. These soils are at present wasteland. montane beech on higher slopes. Topsoils under forest litter are shallow greyish brown sandy loams 5. Central and recent soils southern and silt loams, resting on yellowish brown blocky Recent soils and gley-recent intergrades are stony loams and silt loams. Severe earthquakes in widely distributed on flood plains and low terraces 1929 caused much slip and slump erosion on very of the major rivers, under rainfalls of 60 to steep granite and sandstone slopes in the neighbour- 150 in. hood of Murchison and Karamea. Otira-Waka- Hokitika-Ikamatua soils (90b) are formed from marama soils cover 15 million acres of heavily

74 forested land, the main value of which is watershed CENTRAL REGION, SOUTH ISLAND protection. hills Small areas of sandstone cleared (Region I, Fig. 3 1 3) - * of forest in valleys have reverted to bracken fern The and manuka scrub and attempts are now being central region embraces the mountainous land intervening valleys and basins eastwards made to establish pastures by means of aerial and of main divide for 30 60 miles. In Marl- topdressing and oversowing. the to borough and Canterbury ranges are mainly Higher on the mountains, gley podzols mapped the greywacke, in Otago, Wide as McKerrow soils (46b) are extensive on steep and schist. structural depressions lie between block-faulted moun- to very steep slopes from 3,000 or 3,500 to 5,000 ft tilted, ranges of Central Otago and south-west above the forest line under subalpine scrub, alpine tain grasslands, ft, Canterbury, largest being the Mackenzie tussock and herbfields up to 5,000 the Basin (800 miles), Maniototo Plains and discontinuously up to the limit of vegetation square the (350 Hakataramea and at about 6,000 ft. These soils are developed on square miles), and the Manuherikia The intermontane depressions schist, greywacke, granite, sandstones, and in valleys. are floored with Tertiary clays and sands lying on general the soils on schist are more stable than greywacke. a deeply weathered basement surface and overlain those on the more fractured Small by gravels late Tertiary or early areas developed on argillites, quartzites, marble, thick weathered of Pleistocene age. During late Pleistocene, and ultrabasic rocks on the steep sides of Mt. the the partly filled gravels. A of Arthur Range in north-west Nelson are included valleys were with series defined in places loess-covered, has with these soils. A profile of a McKerrow soil well terraces, been in in some places, in consists of: cut this alluvium and, underlying sediments. Valley sides are bordered 2 in. peaty loam, the 3 in. dark greyish brown silt loam; with crumb structure, with fans, some deposited on top of the terrace 4 in. grey firm nutty silt loam; mottled orange, (Ag), gravels, others cut by lateral planation in the yellow few 7 in. b ownish stony silt loam with mottles’ Tertiary sediments and covered with alluvium and loess. on rock. The main divide (maximum elevation 12,349 ft) McKerrow soils are on steeplands with rainfalls protects it from in the region east of the rain-bearing of 100 to 250 in, and are important watershed westerly winds. The inland basins are further control. protected by subsidiary ranges from the easterly Steepland soils related to rendzinas and yellow- and also south-westerly rains. Hence in some brown earths (Punakaiki and Pikikiruna soils basins annual rainfall is between 13 and 18 (51b)) are present on coastal hills north of Grey- the in., yet summits of neighbouring ranges may mouth and on hills in the Buller and Takaka the receive at least 60 in. At Alexandra the annual valleys. Punakaiki soils occupy steep and moder- rainfall is 13 in., and varies ately steep limestone slopes under rainfalls of 80 the temperature between an average extreme maximum of 90or in to 200 in, and originally supported broadleaved- January and an average extreme minimum of podocarp forest. They are brown granular clay 200F in July, which is a near continental semi-arid loams on yellowish brown silty or sandy clay climate. loams and lie in pockets between limestone out- At of European settlement the vegeta- crops. Pikikiruna soils are developed from marble the time tion on the floors of the valleys and of many of on steep to very steep eastern slopes of the Takaka the lower slopes of the ranges up to 3,000 ft Hill under rainfalls of 50 to 100 in, and previously (3,500 ft in north of Island) was hard supported a podocarp-beech forest. On steep slopes the the and silver Above was domin- profiles are brown granular silt loams on yellowish tussock tussock. this antly Mountain beech and some brown blocky silt loams with marble chips. Puna- tall tussock. beech-podocarp forest grew in the wetter moun- kaiki soils are moderately fertile but limestone podocarp forest in Canterbury and for tains, south outcrops and bluffs limit their use farming. Otago, and podocarp-broadleaved forest on the Pikikiruna soils, stable even on very steep slopes, Seaward Kaikoura Range. The upper forest limit are used for semi-intensive grazing. ranged from approximately 3,500 ft in the south Steepland soils related to brown granular loams 4,500 ft in north. Previously forest was (Eglinton soils, 72a) are formed on the com- to the more extensive and probably clothed all slopes plexes of basic igneous rocks intruded into sed- the about heights, except in semi-arid imentary rocks and are extensive in the upper to these the parts Otago. Above line, and, Buller and Cascade valleys. They are very of central the timber in Otago low-tussock grassland shallow soils developed under beech forest, and central above the prevent 3,000 ft, grassland this cover should be kept intact to rapid at approximately tall-tussock erosion. extended to 4,500 to 5,000 ft where it was suc-

75 3-3 ceeded by alpine herb- and fellfield, which in in most of the deep soils, and where they are turn gave place above 6,000 ft to bare rock, scree, more concentrated solonetric features are well and snow. Extensive erosion that has taken place developed (see Manorburn soil, Chapter 11). in central region is discussed in Chapter 4 6. Cromwell soils are formed on small sand dunes the - Five groups of soils are described: 1. Brown-grey associated with Linnburn-Molyneux soils. earths and related steepland soils; 2. Southern Linnburn-Molyneux include some of the most yellow-grey earths and related steepland soils; fertile soils in Central Otago as well as some of 3. High country yellow-brown earths and related the least productive. With irrigation, the deep steepland soils; 4. Southern podzols and associated soils support intensive sheep farming, fruitgrowing, steepland soils; 5. Southern recent soils from and some market gardening. Careful and efficient alluvium. irrigation is needed to increase productivity with- out the deleterious effects such as waterlogging 1.Brown-greyearthsandrelatedsteeplandsoils or contamination of nearby fertile soils by the Brown-grey earths and related steepland soils flushing of soluble salts. comprise the Conroy-Clare, Linnburn-Molyneux, Grampians-Mackenzie soils (lc) occupy fans Grampians-Mackenzie, Lowburn-Drybread, and (Grampian soils) and terraces (Mackenzie soils) Alexandra-Waitaki soils. They occur in the driest in the eastern Mackenzie Basin and the middle parts of the Central Otago and southern Mackenzie Waitaki valley. Grampians soils are formed on basins. Profiles are characterised by platy struc- silty and sandy fan deposits and in profile re- tured thin brownish grey topsoils and pale yellowish semble the Linnburn-Molyneux soils; calcium brown subsoils with a distinct claypan. Accumula- carbonate is present under the claypan. Mackenzie in tions of calcium carbonate are common in the soils have incipient claypans the stony subsoil. deep subsoil, and in places soluble salts give rise All these soils have annual rainfalls of 16 to 22 in, to solonetzic morphology. and support mostly sparse hard tussock and Conroy-Clare soils (la) occupy undulating, scabweed. Large areas of Mackenzie soils have plant rolling, and hilly terrain on schist and weathered been wind eroded and the cover reduced to Pleistocene gravels with a thin surface layer of scabweed and ephemeral annuals. Grampians- schist loess, under annual rainfalls of 13 to 17 in. Mackenzie soils are used for extensive sheep They support scattered hard tussock and scab- farming and would benefit greatly from irrigation. weed. The soils are predominantly shallow, but Lowburn-Drybread soils (2a), located on the in some places, largely on loess and colluvium, extensive high terraces in Central Otago on which is hard deep soils are developed with clay and calcium the vegetation scattered tussock and loess carbonate accumulations in the subsoil. Conroy scabweed, are formed from a thin cover of greywacke-schist soils are formed on schist terrain, and Clare soils over mixed alluvium (Lowburn are associated with deposits of Pleistocene gravel. soils) or schist alluvium (Drybread soils) under Associated Becks soils formed on Tertiary clays, rainfalls of 13 to 22 in. Topsoils are mostly thin sands, and deeply weathered schist have heavy with platy structures; yellowish brown subsoils gravels textures and blocky structures and contain soluble are massive, and in the underlying a thick salts. Conroy-Clare soils are moisture-deficient pan of brown, clay-cemented gravels overlies and at present are mainly used for extensive and patchy lime accumulations. (See Lowburn profile, very extensive sheep farming. Where practicable Chapter 11.) The soils are used for very extensive irrigation would permit semi-intensive sheep farm- sheep farming, but with improved dryland farming ing. (See Chapter 11 for Conroy profile.) or irrigation their carrying capacity could be greatly Linnburn-Molyneux soils (lb) occupy flat to improved. gently undulating surfaces of the intermediate Alexandra-Waitaki soils (3a), on the steep group of terraces and associated fans throughout slopes of the dry inland ranges under rainfalls of in., formed (Alexandra the dry inland basins of Central Otago. They are less than 18 are on schist formed on schist-greywacke alluvium (Molyneux) soils) and greywacke (Waitaki soils) and support and schist alluvium (Linnburn) with a thin cover depleted hard tussock and ephemeral introduced of loess in some places. Deep Linnburn soils have grasses. Widespread rock outcrops are a charac- particularly Alexandra dark grey sandy loam topsoils overlying compact teristic feature, of the soils. olive silt loam subsoils with coarse prismatic Topsoils are sandy with weakly developed platy yellow structure and calcium carbonate accumulations structures and overlie pale or olive brown at depths below 3 ft. The shallow soils (pre- stony subsoils with a pan of rock fragments in dominantly Molyneux) are mainly loamy sands a matrix of clay. These soils are used for very over gravels with irregular calcium carbonate extensive sheep grazing, but overgrazing by sheep accumulations. Traces of soluble salts are found and rabbits has led to widespread erosion.

76 3*3

2. Southern yellow-grey earths and bearing spectacular screes. Omarama-Arrow soils related steepland soils are used for extensive sheep grazing, but top- dressing greatly increases yields This group comprises the Blackstone-Cluden, and oversowing grasses. Struan-Oturehua, and Omarama-Arrow soils, de- of clover and pasture veloped under annual rainfalls of 18 to 30 in. 3. High country yellow-brown earths and mainly in the intermontane basins surrounding related steepland soils the brown-grey earths. On deep loess, colluvium, group, from Marlborough and alluvium, of high terraces and rolling slopes, In this extending to Acheron topsoils are thicker than in brown-grey earths Otago, are the Tekapo-Molesworth, and and have nutty structure instead of platy. There Dublin, Cass-Katrine, Teviot-Puketeraki, Kai- is a prominent fragipan in olive grey to pale koura-Dunstan, and Tekoa-Bealey soils. They olive brown subsoils, and lime or salt accumula- have developed on greywacke or schist materials, 90 in, tion is rare. Associated shallow and stony soils on under annual rainfalls ranging from 25 to terraces have greyish brown topsoils and yellowish The native vegetation was mainly tall tussock, brown subsoils resembling those of yellow-brown with some mountain beech forest in places. Profiles greyish granular earths. In the eastern part of Central Otago and have brown or brown or crumb yellowish in the Hakataramea valley, profiles are deeper topsoils and brown very friable crumb and have mottled subsoils like the Tima and to nutty or blocky subsoils. Subsoil textures tend Timaru soils described within the eastern region to be slightly heavier than topsoil textures, but periodically (p. 80). no pans are evident. The soils are Blackstone-Cluden soils (4a) occupy rolling and covered with snow and are subject to numerous protected hilly land in the inland basins of Central Otago, frosts. The friable crumbly topsoils are in the upper Waitaki valley, and near Lake Waka- against frost heave and accelerated erosion by the from but tipu. They are developed from schist alluvium litter from decayed tussocks or trees, by fires (Cluden), schist, and loess (Blackstone), and some the destruction of tussocks and their litter greywacke under annual rainfalls of 17 to 30 in, and browsing animals has led to widespread ero- They support hard tussock and scrub. Topsoils sion accompanied by extensive screes. In many are greyish brown nutty fine sandy loams and places on easy rolling to flattish terraces much silt loams; subsoils are olive to olive brown silt topsoil has been removed by wind erosion, and loams with yellowish brown mottles, and are subsoil or stony pavement is exposed. characterised by a massive fragipan especially in In the Mackenzie Basin, western Otago, mid- deep soils (see Cluden profile, Chapter 11). These Canterbury, and inland Marlborough Tekapo- soils are used for extensive sheep grazing but with Molesworth soils (24a) are developed on undulat- topdressing and oversowing they should support ing to hilly moraines, outwash terraces, and fans semi-intensive sheep farming. under annual rainfalls of 25 to 35 in. Parent Struan-Oturehua soils (5a), present on high materials are loess of local origin overlying grey- terraces and fans in Central Otago and south-west wacke and schist morainic till and alluvium. They Canterbury, are formed on greywacke and schist support hard tussock and scrub, but evidence of previous forest alluvium thinly veneered with loess, under rainfalls charcoal in some sites indicates a of 18 to 25 in. They support hard tussock and cover. Tekapo soils are mostly friable, crumb- some scrub. The soils are mainly shallow, with structured silt loams or fine sandy loams, with greyish pale yellowish brown dark greyish brown topsoils and crumb or nutty brown topsoils and profile, structures. In the Maniototo Basin, subsoils are subsoils (Tekapo Chapter 11). Moles- compact and have a pan of clay-coated gravel worth soils are similar except that subsoils are (Struan soils). Oturehua soils have compact sub- slightly compact, indicating a trend towards soils but no pan. Struan-Oturehua soils are used yellow-grey earths. for extensive sheep grazing and some semi- Seasonal moisture deficiency limits the use of extensive farming under irrigation, these soils, but can be corrected by irrigation, as has Omarama-Arrow soils (6a) are derived from been shown on small areas where this has been growth limited by greywacke (Omarama soils) and schist (Arrow tried. Pasture and crop are soils) on steep slopes under rainfalls of 17-35 in. low temperature at elevations of 2,000 ft and per annum. They support mainly hard tussock above. Most Tekapo-Molesworth soils are used grazing with some silver tussock in damp sites, and scrub for extensive sheep but with topdressing in gullies. They are shallow and stony, with a and oversowing are suited to more intensive grass- weak compact subsoil developed where there is land farming. deep loess or fine alluvium. Sheet and gully ero- Acheron and Dublin soils (24b) are mainly flat sion is moderate to severe, some Omarama soils shallow and are to be found on the almost

77 3-3 surfaces of the intermediate group of terraces in greyish brown friable loams with stones, and yellowish the moister parts of inland basins in Central Otago subsoils are brown friable loams over- and the drier basins of Canterbury and Marl- lying fragmented greywacke or schist. Kaikoura- borough. They are formed from a thin veneer of Dunstan soils are prone to erosion, and screes loess overlying greywacke-schist alluvium (Dublin are extensive. Unless the tussock cover can be soils) and greywacke alluvium (Acheron soils) grazed without burning, it may be desirable to under annual rainfalls of 25 to 40 in. They support withdraw large areas from pastoral use in the hard and silver tussock. The soils are mostly less interests of soil and water conservation. than 18 in. deep and have thin greyish brown Tekoa-Bealey soils (26b) occupy large areas on silt loam or fine sandy loam topsoils with weakly greywacke mountain ranges in Canterbury and developed nutty structures. Subsoils of the shallow Marlborough and smaller areas on schist ranges soils are yellowish brown, but those of some in western Otago. They developed under forest associated deep soils are olive grey and slightly on steep and very steep slopes mainly between compact. These soils are used chiefly for extensive 2,000 and 4,000 ft where the rainfall is 40 to 65 in, sheep farming under dryland conditions. Hard and tall tussock have partly replaced the podocarp Cass-Katrine soils (25a) are widely distributed mountain-beech and forests, which now in drier (Tekoa between 1,500 and 3,000 ft on the eastern side of occur as remnants the areas soils) (Bealey the Southern Alps in Otago, Canterbury and and extensively in the wetter areas soils). Marlborough. They are formed from greywacke Tekoa profiles under forest consist of a thin horizon yellowish brown loam, deposits on flat to easy rolling outwash terraces litter on nutty silt and fans and on hilly moraines, Cass soils under merging downwards to angular greywacke detritus. profiles in having rainfalls of 35 to 70 in, and a cover of hard tussock, Bealey under beech forest differ discontinuous pale brown A2 tall tussock, or patches of beech forest, Katrine a weakly structured soils under rainfalls of 70 to 90 in, annually and horizon. Erosion is widespread on these soils and a cover of beech forest and scrub. They have screes are extensive. In the interests of river control desirable greyish brown, friable silt loam topsoils with and water conservation it is considered yellowish Bealey crumb or nutty structure and brown to withdraw most Tekoa and soils, to- gether from (Cass soils) to brownish yellow (Katrine soils) with the adjacent Kaikoura soils, friable, weakly nutty-structured, silt loam sub- pastoral use. soils. On the map some weakly podzolised profiles 4. Southern podzols soils are included with Katrine soils. Cass-Katrine soils and associated steepland are used for extensive grazing. After topdressing Southern podzols and associated steepland soils with phosphate and sulphur, clovers have been include the Lewis-Haast and the Spenser soils. successfully established, showing that by using These soils are extensive under high rainfall on these soils more intensively, grazing pressure on the mountains near the main divide, where there adjacent eroded Tekoa-Bealey and Kaikoura- are profiles with bright yellowish brown subsoils Dunstan soils can be reduced. However, the and thin discontinuous bleached As horizons growing season is short. characteristic of podzols. grey- Teviot soils (25b) are developed under tall Lewis-Haast soils (45a) are formed on (Haast be- tussock on schist uplands of Otago ranging from wacke (Lewis soils) and schist soils) 1,800 to 3,500 ft, with a rainfall of 25 to 40 in.; tween 1,000 and 4,500 ft under annual rainfalls of Puketeraki soils (25b) in Canterbury under tall 60 to 100 in. They are podzolised soils with thin loams tussock on high terraces and easy greywacke pale brown silt loams or sandy overlying yellowish mountain tops ranging from 3,500 to 5,000 ft, thin pale grey As horizons of fine sand on with a rainfall of 40 to 65 in. Topsoils are powdery, brown and strong brown subsoils. Where the granular sandy loams and silt loams with few beech or scrub vegetation is disturbed, particularly gully, rock fragments, and subsoils are silt loams or at higher elevations, sheet, and scree erosion for sandy loams and occasionally clay loams (see occurs. The soils are therefore suitable only Puketeraki soil, Chapter 11). These soils are used protection forests. for very extensive sheep grazing but show con- Spenser soils (46a) occur under tall tussock, siderable erosion. subalpine scrub, and herbfield, with high rainfall ft. Kaikoura-Dunstan soils (26a) occupy steep and on greywacke and schist ranges above 3,500 greywacke greyish brown loams generally very steep slopes (270 to over 400) on Topsoils are thin peaty (Kaikoura) and schist (Dunstan) between 2,000 but thick and in alpine basins. Subsoils are pale loams, flattish and 6,000 ft under annual rainfalls of 35 to 60 in. olive stony with mottling on by hares, The dominant vegetation is tall tussock with sites. Grazing deer, thar, and chamois gully in minor scrub and beech forest. Topsoils are thin has caused much sheet and erosion, and

78 3-3 the interests of watershed protection grazing broadleaved forest in swamps. Correlations be- animals should be strictly controlled. tween this pattern of vegetation and the soils are not clearcut because numerous fires in pre- 5. Southern recent soils from alluvium European times modified the vegetation principally Selwyn-Waimakariri soils (90a) of eastern the by reducing the area of forest and scrub. have been include region extended to soils on The soils are discussed under eight headings: flood plains low recent alluvium of and terraces 1. Southern yellow-grey earths and related steep- fans and on recent throughout the central region. land soils; 2. Southern yellow-brown earths, The lower flood plains have chiefly sandy and podzols and related steepland soils; 3. Southern stony soils and an incomplete cover of herbs, rendzinas and associated soils; 4. Southern brown grasses, plants. and occasional silver tussock granular loams and clays and related steepland Deeper loams loams sandy and silt occur on the soils; 5. Southern yellow-brown sands; 6. Southern higher parts of flood plains and on fans (Wai- the recent soils; 7. Southern gley and saline gley soils; includes makariri soils), where the vegetation and 8. Southern organic soils. hard grasses, herbs, silver and tussock, and and The distribution of these classes on the various of matagouri and some indigenous broom. thickets land forms of the region is as follows: The stony and bouldery soils are commonly Landforms Soil classes droughty low fertility, but and of natural the I. Plains Shallow and stony associates deeper, more moisture-retentive sandy loams and of yellow-grey earths silt loams are moderately fertile and some are n sdo line gley soils used for cropping and forage crops. Organic soils Yellow-brown sands 2. Downlands hills Yelliod nas, EASTERN REGION, SOUTH ISLAND and bgroey 7tahsilren (Region J, Fig. 3 1 3) 3. Steep lands Steepland soils related to - - yellow-grey earths The eastern region extends for 260 miles along Steepland soils related to yellow-brown the east coast of the South Island from the Ashley earths 4. Schist uplands oo brown earths River valley north of Christchurch to the Clutha River valley south of Dunedin. It includes five 5. Hilly volcanic peninsulas Brown granular loams and distinct land forms: 1. Plains consisting of al- associated soils. luvial fans, flats, and swamps; 2. Downlands and 1. Southern yellow-grey earths and related hills composed of a variety of rocks including soils Tertiary sandstones and Pleistocene and Recent steepland alluvium, gravels, and loess; 3. Steeplands of the Yellow-grey earths are the dominant soils of greywacke Where and schist ranges; 4. Schist uplands of the subhumid downlands of the east coast. gentle but eastern Otago; and 5. Hilly volcanic peninsulas relief is the loess mantle is continuous, near Christchurch and Dunedin. The relief of the with increasing relief it becomes thinner and the region was strongly modified by Quaternary soils are formed in part from the underlying Hence Glaciation when the mountains were rapidly Tertiary sandstones and mudstones. the pattern pre-Maori eroded, the Canterbury Plains were built, and detailed soil is complex. In probably loess was deposited over the downlands and times the downlands supported mixed peninsulas. podocarp and broadleaved forest. At the time of The climate is cool, with warm moderately dry European settlement nothing of this remained and summers and cool moist winters with night frosts. the yellow-grey earths supported mainly hard and Mean annual temperature at sea level at Christ- silver tussock grassland. Today the arable down- church is 52-90F, and at Dunedin 51-70F. Average lands are under cultivation and used for mixed in. farming. Productivity is limited by annual rainfall is from 25 to 35 Over much of the compact the region (lowest 18 in.), with a summer moisture subsoils, which encourage waterlogging in winter deficit most marked in Canterbury where Fahn and accelerate summer drought. Topsoils are winds are strongest. At high elevations, both uniformly silt loams with fragile aggregates and prone coastal and inland, annual rainfall increases to at the soils are accordingly to sheet erosion. least 50 in. (Banks Peninsula) and humidity in- Genetic relationships of yellow-grey earths are creases. Vegetation at the beginning of European expressed in the subsoil characteristics of soils settlement consisted of small areas of podocarp developed on loess. Under low rainfalls (20 to 23 and beech forest in wetter situations and mainly in.) subsoils are pale and have weak horizon tussock grassland (silver tussock and hard tussock) development and mottling; those under moderate plains, on hills, downs, and well drained parts of the rainfalls (20 to 30 in.) have distinct iron staining with flax, raupo and small patches of podocarp- and mottling and a weakly structured B horizon

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over a massive fragipan; and those under higher silt loams with distinct orange mottling. Drainage is impeded rainfall have more clay, a nutty structured B through the soil and the soils waterlog horizon, and an underlying fragipan with coarse readily, especially on the Mairaki Downs where prismatic structure and distinct grey veins. Charac- the subsoil is a clay loam. Waitohi soils in the porous higher ters of subsoil and fragipan are also influenced in Oamaru district are more and of part by local variations in the thickness of the natural fertility. Clydevale (11b) formed loess deposits and by the nearness of buried soils Te Houka and soils are downlands in lower Clutha to the surface. on the schist-loess the in. Ngapara soils (4b) are formed on greywacke valley under annual rainfalls of 23 to 30 Te have loam loess in the Waitaki valley under rainfalls of 20 Houka soils silt topsoils with crumb profiles in. dark grey yellow silt loam to 23 in. The consist of 9 structure, and compact mottled friable fine sandy loam with crumb structure, on subsoils with blocky structure. They are of low 8 in. olive brown firm silt loam with blocky to medium natural fertility and supported hard Clydevale structure resting on olive silt loam, very firm with tussock in their natural state. soils hard coarse prismatic structure and weak accumulation from coarser loess supported silver and fertility. Both of calcium carbonate occurs in the subsoil. Nga- tussock and are of medium soils are prone para soils on rolling slopes are subject to sheet to sheet erosion but are successfully used pastures and wind erosion. The related Tima soils on for mixed farming. Good are obtained schist loess in the Clutha valley are mainly on with molybdic superphosphate topdressing. moderately steep slopes and are susceptible to Opuha and Warepa soils (12a) are extensive on downlands (annual 30 40 in.) both tunnel-gully and sheet erosion. the wetter rainfall to Kauru soils (7a) are developed in north Otago of south Canterbury, and north and south Otago. generally higher under an annual rainfall of 20 to 30 in., from Opuha soils are at elevations and is sandstones partly covered with loess. They have further inland than Warepa soils. Rainfall well friable silt loam topsoils and clay loam subsoils distributed and droughts are infrequent. An Opuha greyish which are coarsely prismatic and have pale grey profile is 7 in. dark brown friable silt veins. The subsoils are considered to have been loam with weakly developed crumb and nutty 10 in. pale yellowish brown firm blocky weathered prior to the deposition of the loess. structure, yellowish Timaru-Claremont soils (8a) are extensive in silt loam with strong mottling on brown have south Canterbury and north Otago. They are massive silt loam. Warepa soils more strongly poorly formed on loess-covered downlands under annual clay-enriched subsoils. Both sets of soils are prone rainfalls of 23 to 30 in. Topsoils are silt loams drained on easy slopes, and they are to sheet infestation by with fragile crumb structure and subsoils are erosion under cultivation and to have gorse compact heavy silt loams with fragipans and and broom. from a coarse blocky structure (see Timaru silt loam, Karitane soils (15a) are developed the Chapter 11). The soils are widely used for intensive thin veneer of loess and overlying Tertiary sand- have mixed farming. On gentle slopes internal drainage stones in subhumid coastal Otago. They have profiles is slow and the soils are poorly drained in winter. moderate natural fertility and of The related hill soils on Banks Peninsula are dark grey nutty-structured heavy silt loams on blocky loams. susceptible to tunnel-gully erosion. strongly mottled clay Haldon and Tengawai steepland soils (10a) Waikoikoi and Crookston soils (16a), on the loess downlands Otago rainfalls occupy the steep slopes of the drier coastal country of south under 35 40 in., low natural and the drier lower slopes of the foothills under of to are of to medium profile is European silver-hard tussock grassland. A Haldon fertility. At the time of settlement they 6 in. dark greyish brown stony silt loam on shat- supported mixed hard tussock and red tussock. profiles A Waikoikoi profile is 9 in. dark grey friable tered greywacke. Deeper on colluvial of pale yellow deposits are less droughty and their pastures silt loam with nutty structure, 15 in. grade yellowish brown respond well to superphosphate. They into firm silt loam with mottles and grey- pale yellowish brown firm Hurunui steepland soils on the flanks of the nutty structure, on silty has grey wacke foothills, which form the western boundary clay loam which is mottled and veins between prisms. Drainage is of the Canterbury Plains and have higher annual extending coarse rainfall. naturally slow on easy slopes where mole and tile drains Both suited Waitohi-Mairaki soils (lla) are widely distribu- are necessary. soils are well production of lambs and cattle, with some ted on loess-covered high terraces within the to Excellent responses super- annual rainfall range of 23 to 30 in. Topsoils cereal cropping. to phosphate obtained. are soft crumb-structured silt loams, and subsoils and molybdate are (16c) formed are compact medium and coarse blocky heavy Kakahu and Kaitangata soils are

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greywacke Ashwick have on greywacke hills with a thin veneer of Ruapuna, and soils shallow or loess (Kakahu soils) or schist loess (Kaitangata stony profiles possessing few of the characteristics yellow-grey developed from soils). They have dark grey silt loam topsoils of southern earths and pale yellow compact silt loam subsoils. Both fine-textured materials. They are classified as yellow- are of low natural fertility and their pastures shallow and stony soils associated with gorse. is grey readily revert to manuka and Land use earths. mainly extensive grazing, but with fertilisers and 2. Southern yellow-brown earths, podzols, and good pastoral management the soils are suitable for more intensive farming. They are also suitable related steepland soils for commercial forestry. The Hurunui, Wehenga, Pukekoma, Maunga- group, Lismore and Steward soils (9a) are formed on tua, and Leith soils, which constitute this greywacke gravels loess, parts coarse mantled with are located in the humid of the eastern which is up to 15 in, thick. They are shallow soils region including the western margin of the Canter- with low natural fertility (see Chapter 11). Lis- bury Plains and uplands of eastern Otago. more soils are extensive on the older fans and Hurunui soils (30b) are extensive on the steep high-level terraces of the Canterbury Plains, and and hilly foothills along the western edge of the Steward soils on similar sites in the Waitaki valley. Canterbury Plains. They are developed from grey- Under the subhumid climate of the region they wacke under an annual rainfall of 35 to 45 in, hard are droughty soils subject to wind erosion when and under mixed vegetation. Silver and cultivated. Lismore soils can be raised to moderate tussock is extensive on drier areas and manuka productivity under dryland farming or to high fern and beech forest grow on higher-rainfall areas. pastoral production under border-dyke irrigation. Forest was probably widespread before the ex- profile Steward soils are more stony and a thick cemented tensive burning began. A common on talus subsoil makes them liable to waterlog under shows 6 in. dark grey stony silt loam with nutty irrigation. structure over brownish yellow stony silt loam. Inland, with increasing rainfall and elevation, The Hurunui soils have moderate natural fertility, Lismore soils merge into Ruapuna soils (19b). are slow to erode, and with aerial oversowing These soils originally carried beech forest, which and topdressing make excellent pastoral land for was replaced by hard tussock grassland before sheep breeding. European settlement. A profile developed under Wehenga and Pukekoma soils (27b), of low about 40 in, annual rainfall shows 6 in. brownish natural fertility, are extensive on schist uplands pale grey silt loam with soft crumb structure on west of Dunedin at altitudes ranging from 700 grading down yellowish brown bouldery silt loam to 2,000 ft. They were formed under annual rain- into boulders and stones. The natural fertility is falls of 25 to 35 in, and a red-fescue or silver- pastoral productivity be have profiles low but moderate can tussock vegetation. Wehenga soils of obtained with lime, superphosphate, and molyb- dark greyish brown friable silt loams on yellowish date. brown friable silt loams. Pukekoma soils are less Ashwick soils (19b), found in the Fairlie basin brown and have firmer aggregates. Unlike yellow- do under annual rainfalls of 27 to 40 in., are similar grey earths, both soils are free-draining and present in many properties to Ruapuna soils but are not dry out in summer. At they are used more droughty. for extensive grazing but with appropriate ferti- Hororata-Mayfield soils (19a) are associated lisers and pasture management should become grazing with Ruapuna soils, but are on lower terraces. moderately productive land for sheep and With decreasing annual rainfall below 35 in, they cattle. grade into Templeton-Eyre soils. When first Maungatua and Leith soils (43b) are located Otago. Maunga- settled they supported silver and hard tussock in the cold moist areas of eastern with small areas of forest that were previously tua soils are formed under tall tussock and sub- 2,500 ft. more extensive. Mayfield soils are commonly silt alpine herbs on schist uplands above loam), profile is loams (but range from sandy loam to clay A Maungatua on an easy rolling slope pale grey dark greyish brown and friable in the topsoil 5 in. dark grey firm silt loam, 3 in. mottled in loam, in. pan yellowish brown and yellowish brown and slightly compact the silt J red iron over subsoil. Hororata soils are greyish brown stony silty clay loam. This soil is very strongly leached, silt loams on yellowish brown stony silt loams. has very slow drainage, and is not suitable for production. Leith lie Both soils are moderately to strongly leached and pastoral or forestry soils are used for mixed farming. Good cereal crops between 600 and 1,200 ft on hills north of Dunedin may be obtained on Mayfield soils. under podocarp-broadleaved forest. The Leith The Lismore, Steward, Hororata, Mayfield, profile is somewhat similar to that of Maungatua

81 has but commonly a surface layer of brown mor Highcliff soils (in 67b) were formed on the humus. basalts of Otago Peninsula under broadleaved- podocarp forest and an annual of 25 3. Southern rendzinas and associated soils rainfall to 35 in. Profiles consist of 7 in. dark brown friable Rendzinas are confined to black clay soils silt loam on 6 in. of brown nutty clay loam con- developed Tertiary limestones on small outcrops of pieces principally taining of basalt. These soils are in south Canterbury and north Otago. They are on hilly land and when farmed with the associated too small in extent to show separately and are Warepa soils on rolling land are capable of intensive included Waikakahi formed from either with soils pastoral production. associated calcareous rocks or with Waiareka- Cargill soils (68a) also are formed from basaltic Oamaru soils formed from a complex of basaltic rocks, but on the moister hills of the Dunedin tuffs and calcareous sediments. podocarp district under forest up to about 3,000 ft Waikakahi soils (49a) are rendzic intergrades A yellow-grey and under snow tussock above this altitude. to earths and are developed on cal- profile has 6 in. dark brown firm silt loam with careous sandstones exposed by erosion of loess basalt stones on 18 in. reddish brown stony clay. on rolling to hilly land in the Waihao valley of With Cargill and associated south Canterbury. A detailed profile is described topdressing, the Warepa soils derived from loess and solifluction in Chapter 11. Compared with a yellow-grey deposits are successfully used for sheep and cattle earth such as Timaru silt loam the soils have a breeding and fattening. thick, more friable, more fertile topsoil and a Stewart-Summit soils (in 70a) are formed on less mottled and compacted subsoil, but inter- steep slopes of Banks Peninsula under podocarp- grades close to true rendzinas are rare. Waikakahi. broadleaved forest and an annual rainfall of 40 soils are extensively used for mixed pastoral and to 50 in. Stewart soils, derived from basalts, have crop farming and are susceptible to sheet erosion. profiles of dark brown granular silt loam on Oamaru soils (in 67a) are developed from brown rocky clay loams. They have high natural limestone under silver tussock and an annual fertility and have produced high yields of cocksfoot rainfall of 20 to 25 in. A representative profile is seed in the past. Without fertilisers they still 10 in. dark grey granular clay loam or dark brown support fair pastures after farming for more than blocky clay loam grading into limestone. The 100 years and with fertilisers become highly soils are highly fertile but subject to severe drought. productive. Summit soils are derived from loess With the associated Waiareka soils they are used and underlying basalt. Their profiles have yellowish for cereal crops, market gardening, and fat-lamb brown silty subsoils and are related to yellow-brown raismg. earths. They need fertilisers to maintain good 4. Southern brown granular loams and clays pastures. and related steepland soils 5. Southern yellow-brown sands The brown granular soils are developed from basaltic lavas of Banks and Otago Peninsulas and Kairaki soils (53a) are yellow-brown sands other small outcrops elsewhere in the eastern formed on coastal sand dunes associated with region. Practically all of the outcrops have been gravelly beaches. They are extensive north and covered with loess now largely eroded making it south of Banks Peninsula, and occur in coastal difficult to map areas formed entirely from volcanic bays as far south as Dunedin. Profiles vary widely materials. However, profiles from volcanic ma- and commonly show between 2 and 7 in. of dark grey grey terials are available and are used for the descrip- loamy sand over olive loose sand. The tions below. soils are very droughty and of doubtful value for Waiareka soils (in 67a) occur in north Otago farming but in places may be suited for commercial derived from basaltic tuffs under a subhumid forestry. On some dunes, burning of the original climate and an annual rainfall of 20 to 25 in. A tussock and shrubs has allowed severe wind profile is described in Chapter 11. They are black erosion and has required planting of marram nutty clays, very sticky when wet, and are known grass for stabilisation. as ’tarry soils’. In summer they dry out and fissure 6. Southern deeply. They must be cultivated at optimum recent soils moisture to obtain a fine tilth, but their fertility Recent soils from alluvium are widely distributed is high and with suitable management they are over the flood plains and low terraces of the productive highly for market gardening. Inter- numerous rivers of the region. The alluvium grades to Oamaru rendzina soils are common consists chiefly of greywacke detritus from the where the tuffs are interbedded with limestone axial ranges and foothills, but in a few places is deposits. derived from Tertiary sandstones such as the

82 3-3 potassium-rich glauconitic sandstone in the valley of soils are used for pastoral farming with occa- inland of Willowbridge. Many recent soils have sional cropping. been separated on detailed surveys but for pur- 7. Southern gley gley poses of this description they have been grouped and saline soils in the following units-Selwyn-Waimakariri, The gley soils occupy depressions of the coastal Templeton-Eyre, Taitapu, and Barrhill-Kowai lowlands where ground water is close to the soils. surface for most of the year. With increasing Selwyn-Waimakariri soils (90a) represent the wetness they grade into organic soils such as soils on freely draining parts of flood plains of Waimairi peaty loam. the Ashley, Waimakariri, Selwyn, Rakaia, Ash- Temuka soils (in 85a) are formed from poorly burton, Hinds, Rangitata, Opihi, Waihao, Wai- drained silty alluvium with some organic matter in taki, Taieri, and Clutha rivers. They range from the native raupo and 11ax vegetation. They texture from stony sands to deep silt loams, and have profiles of dark grey silt loam over bluish their fertility and usefulness vary accordingly. grey silt loam or clay loam, with orange mottles A profile of Selwyn sandy loam is described in common in both horizons. A detailed profile of Chapter 11. Waimakariri soils have accumulated Temuka silt loam is given in Chapter 11. The greyish more slowly and have a brown topsoil natural fertility is high and the soils are highly that grades into a yellowish brown friable subsoil. productive when suitably drained. However, the Where the soils are deep fine sandy loams and improved soils dry out in summer and spray silt loams they are highly fertile and are widely irrigation is used on some dairy farms on city used for cropping. milk supply. Templeton-Eyre soils (91a) represent the soils Motukarara soils (in 88a) occur on saline on free-draining intermediate terraces of the river marshes near the coast, particularly around Lake valleys of the region. The terraces are now above Ellesmere. The ground water is saline and as the the level of river flooding but receive small de- salinity decreases inland the soils grade into posits of dust from the river beds. Profiles are Taitapu soils. In their natural state Motukarara mostly silt loams to sandy loams in texture and soils support salt-tolerant plants but with drainage greyish grading are dark brown in the topsoils they can be converted to pastoral lands with some below 9 in, into pale yellowish brown in the sub- cropping on less saline areas. Topsoil textures detailed peaty soils, which are firm rather than friable. A range from silt loams to sandy loams to profile of Templeton silt loam is given in Chapter loams and from silt loams to sands in the subsoil. 11. The deep silt and sandy loams are widely used for mixed crop and pastoral farming and some 8. Southern organic soils have been successfully irrigated. The shallow silt Organic soils are restricted to very swampy loams (mainly Eyre have limited and sandy soils) sites on the coastal lowlands where water tables for dryland because droughtiness use cropping of were permanently at the surface and where de- irrigation for intensive Templeton- and require use. composing organic matter accumulated above the Eyre soils can be considered as intergrades be- mineral soil. tween recent soils and yellow-grey earths. Waimairi peats and peaty loam (in 81a and 85a) Taitapu soils (92a) occupy swampy parts of are derived from decomposed remains of sedges, plains flood and low terraces (see Taitapu silt rushes, and flax mixed with some silt and clay loam, Chapter 11). They are mainly silt loams of alluvium. The soils are very dark greyish brown fertility drainage high natural and with are capable to dark brown peaty loams with granular structure pastoral of intensive use for mixed cropping and on very dark brown loamy peat. When the swamps farming for dairying- or are carefully drained and managed they become (93a) in Barrhill-Kowai soils are narrow strips moderately to highly productive market-garden or bordering river banks where wind-blown dusts dairying land. Additions of copper are required have (2 per year accumulated rapidly mm approxi- for onions and to offset the high molybdenum mately). They are fine sandy or silty soils with content in pasture. weakly developed structure and when cultivated are susceptible wind erosion. Barrhill soils are to SOUTHERN REGION, SOUTH ISLAND formed under silver tussock and an annual ram- (Region K, Fig. 3 1 3) fall of 27 to 35 in. A detailed description of Barrhill - - fine sandy loam is given in Chapter 11. Kowai The southern region comprises Fiordland, South- district soils are formed under mixed tussock with beech land, Stewart Island, and the Catlins of is forest further up the valleys where annual rainfalls south Otago. The terrain in Fiordland moun- are between 35 and 45 in. per annum. Both sets tainous but eastward is predominantly rolling and

83 hilly with extensive plains along the Mataura, In their properties they are closely related to the Oreti, Aparima and Waiau rivers. Stewart Island, moister yellow-grey carths of the eastern and 30 miles south of Bluff is a forest-covered island north-eastern regions and they may be regarded yellow- of steep to hilly land about 670 square miles in as intergrades between yellow-grey and area. brown earths. Six soils are mapped; Pukemutu, Rocks of the mountain ranges include granites, Aparima, Ohai, Waikoikoi, Crookston, and Rua- gneisses, and diorites in Fiordland and Stewart puna. The three last-named are also mapped in Island, and greywackes, sandstones, mudstones, the adjoining eastern region and their descriptions and limestones elsewhere. The plains are underlain are given with that region. by gravels, and extensive dunes border the south Pukemutu soils (15b) occupy high loess-covered coast. Loess mantles the downlands and plains, terraces in the Oreti valley. Annual rainfall ranges ranging from 3 to 6 ft thick in the central and from 30 to 45 in. They were under red tussock at eastern parts but becoming progressively thinner the time of European settlement but may have to the west. carried forest earlier. Topsoils are firm nutty Mean annual temperature at sea level is 490F. dark greyish brown silt loams, a paler Az horizon per present Rainfall is about 50 in. annum along the coast containing rusty brown concretions being grey near Invercargill, falling to 30 in, in the inland in places. Subsoils are pale firm silty clay valleys between Mossburn and Gore. It rises loams with yellowish brown mottles and with a rapidly westward to 300 in, in Fiordland and in coarse prismatic structure, overlying a shattered south-eastern areas to about 60 in. In those parts fragipan. Under rainfalls of 30 to 35 in, textural paler, of Southland where the rainfall is below 35 in. differences are less marked and colours are (the inland valleys) hard-tussock and silver-tussock but the concretionary horizon is very well developed iron grassland was the dominant native vegetation. and frequently cemented to form a massive Where the rainfall reached 45 in. red tussock pan. The soils have very slow drainage. They have was dominant with patches of podocarp and low base saturation, show moderate clay illuvia- broadleaved forest. On Stewart Island and the tion and weak to moderate iron illuviation. coastal lowlands and hills, with annual rainfalls Aparima soils (17a) are developed on loess of more than 45 in., the native vegetation was derived from basic greywacke in the Otautau and podocarp-broadleaved forest, generally rimu domi- Nightcaps districts under annual rainfalls of less grassland. nant and kamahi subdominant. White pine, black than 40 in, and under red tussock The pine and totara were widely distributed on river topsoils are greyish brown firm nutty silt loams plains and swamps. At higher elevations and on with some mottling in the lower parts; the sub- ridges near the coast southern rata is still dominant. soils are very firm silt loams with reticulate mottl- Large areas of mountain beech forest occur on ing extending through the fragipan. The soils are the mountains of Fiordland, and silver beech on very strongly leached and show weak iron and the low hills of western Southland and the Long- moderate clay illuviation. Drainage is impeded wood Range. There is, in general, a close relation by the fragipan, but the soils drain faster than the between the composition of the vegetation and Pukemutu soils. They are mainly on flat to prod- the degree of soil development although some undulating land used for intensive fat stock species, such as silver beech, grow on a wide range uction. of soils. Ohai soils (18a), on rolling and hilly lands in The soils of the southern region are discussed the Aparima valley, have developed on a complex yellow- under the following headings: 1. Southern mixture of shallow loess over weathered Pleistocene grey earths and intergrades; 2. Southern yellow- conglomerates, sandstones, and siltstones. Profiles brown earths; 3. Southern podzols and related differ considerably in texture and structure accord- soils; 4. Steepland soils related to podzols; 5. ing to their parent materials, but most of them Southern yellow-brown sands; 6. Southern yellow- have greyish brown topsoils with soft granular brown loams; 7. Southern brown granular loams structure on yellow blocky clay loams with many and associated soils; 8. Steepland soils related to pale grey and rusty brown mottles. They are southern brown granular loams; 9. Southern strongly leached, of low natural fertility, and phosphates organic soils; 10. Southern recent soils from require heavy dressings of lime and to alluvium. maintain good pastures. Ohai soils are well suited to forestry. 1. Southern yellow-grey earths (and intergrades) 2. Southern yellow-brown earths Yellow-grey earths in the southern region are found in the inland valleys where the annual rain- Yellow-brown earths are widespread on the fall is below 35 in, and is unevenly distributed. humid downlands and hills of Southland and south

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Otago. They comprise the Waikiwi, Wairaki, are greyish brown friable coarse nutty-structured Hauroko, Owaka-Waimahaka, Spooner-Rosedale heavy silt loams, and subsoils brownish yellow and Lillburn soils. firm coarse-blocky-structured clay loams with Waikiwi soils (27a) are extensive on the loess- mottles. The easy slopes are in improved pasture covered undulating terrace land between the and are used for fattening stock. The hilly land Mataura and Waiau valleys. They supported red carries beech forest and when cleared is well tussock with some podocarp-broadleaved forest suited to exotic conifers, at the time of European occupation, but earlier the land was probably all in forest. A detailed 3. Southern podzols and related soils description of Waikiwi silt loam is given in Chap- Tautuku-Hinahina soils (43a) are widespread on 11. They are friable firm loams ter to silt with wet coastal hills under podocarp-broadleaved free drainage and after applications of lime, forest with annual rainfalls of 50 to 60 in. Parent phosphates, and potash, are widely used for fat materials range from greywackes in the east to stock production. The soils are strongly leached Tertiary sediments in the Waiau valley in the west. but little iron illuviation. Cobalt show clay or Hinahina soils are weakly and moderately pod- deficiency in Southland was first discovered on zolised yellow-brown earths. Tautuku soils are soils. Wairaki soils are somewhat similar these moderately podzolised yellow-brown earths, with except are derived from sediments con- that they thick 02 horizons, bleached As horizons, and more iron and have brown colours in taining moderate to strong clay, iron, and humus illuvia- both and subsoil. topsoil tion (see Chapter 11). Both soils are largely in Hauroko soils (28a) are derived from mudstones cut-over native forest which is slow to regenerate and hilly lands in sandstones on the rolling and and could be replaced by exotic conifers. western Southland. They are developed under Okarito soils (44a) are mapped on coastal mixed beech and podocarp forest and under an terraces, and their properties are similar to those annual rainfall of 50 to 80 in. The surface soil is described in the western region. a peaty loam, which rests on greyish brown thin Longwood soils (44b) are gley podzols derived and yellowish brown clay loam with nutty to from basic greywackes of the moderately steep blocky structures. They are strongly leached soils cold wet Longwood Range of Southland under with some podzolised profiles in easier and well silver beech and subalpine scrub and tussock. drained sites and are best used for forestry. They are best left in native vegetation. Owaka-Waimahaka soils (29a) are formed on rolling to hilly land, from greywacke and shallow 4. Steepland soils related podzols loess. Topsoils are greyish brown friable silt loams to Stewart with a nutty structure, and subsoils are yellowish The dominant soils of Fiordiand and of podzolised yellow-brown brown firm clay loams with blocky structures. Island are steepland podzols, gley podzols formed in The podocarp-broadleaved forest under which earths, and a high from gneiss, these soils were formed is now mainly replaced cold climate with rainfall, schist, granitic Titi- with pastures used for stock breeding and fattening. and rocks. They are mapped as Resolution Owaka soils are moderately to strongly leached; raurangi or soils. Waimahaka soils are strongly leached with some Titiraurangi soils (45c) cover extensive areas of from level 3,000 ft tendency to podzolisation shown by patches of a the Fiordiand mountains sea to in. pale brown and weakly structured subsurface and under annual rainfalls of 80 to 300 Their precipitous. horizon in some profiles. slopes range from steep to They loams loams, Spooner-Rosedale soils (29b) represent the soils consist of thin stony and sandy and developed on the greywackes of the Kaihiku, include steepland equivalents of the strongly yellow-brown podzols gley- Hokonui, and Taringatura Ranges under tussock leached earths, and podzols. both beech podocarp- grassland and an annual rainfall of 35 to 45 in. The soils carry and be Topsoils are greyish brown friable silt loams with broadleaved forest which should retained; is by a nutty structure resting on yellowish brown stony even under forest there considerable erosion silt loams. Slopes are mainly moderately steep, debris avalanches. with small areas of rolling land. With aerial top- Resolution soils (46b) are extensive on the dressing the soils maintain excellent pastures for moderately steep to steep uplands of Fiordland stock breeding and fattening. under subalpine to alpine scrub and grassland. Lillburn soils (29c) are formed under beech They are similar to the McKerrow soils of the granitic forest, beech-podocarp-broadleaved forest, and western region but are formed largely on red tussock, from Tertiary siltstones and sand- rocks. At present the soils are of no value for stones. Annual rainfalls are 35 to 55 in. Topsoils agriculture or forestry.

85 3*3

5. Southern yellow-brown sand? probably once grew on them. Topsoils are dark Riverton soils (53b) occupy a discontinuous brown very friable silt loams with fine nutty to strip of old beachlands along the southern coast. granular structure, and subsoils are dark brown The annual rainfall is 45 to 80 in., and their to yellowish brown friable silt loams with nutty to natural vegetation is tussock, scrub, and forest. In blocky structures. They are used largely for fat degrees of soil development profiles vary widely stock production but are cropped more frequently from loose yellow sands with a thin grey topsoil than other Southland soils and so are well suited to more weathered and leached loamy sands with for intensive mixed farming, a distinct brown B horizon. The natural fertility 8. Steepland soils brown is low to very low, but in places pastures have related to southern granular loams been established by topdressing. Wind is a serious problem since it causes erosion after cultivation Windley soils (71a) are derived from basaltic and malformation of exotic trees. rocks on high steep ranges in the Mossburn district. They are stony clay loams with shallow 6. Southern yellow-brown loams granular greyish brown topsoils on yellowish Te Anau-Monowai soils (59a) have developed brown subsoil. These soils erode rapidly and the on moraines of the Last Glaciation (from granite, present tussock, scrub, and beech forest should gneiss, and diorite) in the upper Waiau valley, be retained for water conservation. under rainfalls of 40 to 60 in. Vegetation is stunted Eglinton-Hollyford soils (72a) formed from fern and scrub with patches of beech forest that Paleozoic igneous and associated sedimentary was more widespread in pre-European times. Te rocks in the western and northern parts of South- Anau soils are mostly stony loams and sandy land, include intergrades between steepland brown loams with dark greyish brown very friable granular loams and yellow-brown earths. The granular topsoils, bright brownish yellow to soils are mostly covered in beech forest but some yellowish podocarp-broad- red very friable granular subsoils and of the Hollyford soils support hard cemented pans. They are very strongly leaved forest. Eglinton soils are in areas where profiles leached although of only medium pH; their clay the annual rainfall is 45 to 80 in., and their content is low but cation-exchange capacities are have a thin peaty litter overlying dark greyish fairly high (20 to 25 me.%) and allophane, hydrous brown stony loam on dark yellowish brown to micas and vermiculite have been identified. They brownish yellow stony loam. Hollyford soils, have affinities with both yellow-brown loams and under higher rainfall (80 to 250 in.) have thicker strongly leached yellow-brown earths. litters and thinner topsoils, and show signs of podzolisation. Monowai soils occupy stony outwash terraces weak and have gravelly subsoils. They support hard Takitimu-Bryneira soils (72b) are found in the tussock and manuka but with heavy dressings of same localities and on rocks like those that have fertiliser could maintain pastures for sheep and given rise to the Eglinton-Hollyford soils, but cattle. they have developed under tall tussock and sub- alpine scrub at high elevations between 2,700 and 7. Southern brown granular loams and grey 4,500 ft. Their profiles have topsoils of dark associated soils very friable peaty silt loams on dark greyish The Malakoff soils (in 67b), south of the Taki- brown very friable stony loams on brownish timu Mountains on hills of basic volcanic rocks, yellow friable gritty loams. The soils resemble are formed under tussock and broadleaved shrubs the Kaikoura soils further north and are likewise and rainfalls of 40 to 45 in. Topsoils are friable susceptible to severe sheet and scree erosion. dark brown granular stony loams to very dark 9. Southern organic soils reddish brown nutty silt loams and subsoils are dark brown nutty heavy silt loams. The soils Otanomomo soils (81b) (described in Chapter 11) have high cation-exchange capacities (50 me.%), occur on peat bogs near Bluff and on Stewart are weakly leached, but are very low in available Island. The surface layers are raw and at present phosphorus. They are used for range grazing. unsuitable for agricultural use, but the more Drummond soils (68b) are mainly on the low decomposed layers below might be made suitable terraces of the Southland plains between the for pasture if the surface layers were removed. Oreti and Aparima rivers, and in the Waiau valley. Kaherekoau soils are formed over granite, They are derived from thin (1-3 ft) loess-like drift schist, and a variety of other rocks, in places with on gravels and are developed under a moist very high rainfall under snow grass, sedges, and climate (35 to 45 in, annual rainfall) and under subalpine scrub. They are located on the steep predominantly tussock vegetation although forest slopes of the Kaherekoau Mountains of south

86 3*4

Fiordland (annual rainfalls over 100 in.), on ments, greywackes, and loess. They have dark Stewart Island, and on the easy rolling slopes of brown A horizons merging into brown or dark the Blue Mountains in south-west Otago (over grey A2 horizons, pale brown mottled B horizons grey 60 in. rainfall). Their profiles have 3 to 5 ft of and greenish G horizons with yellow mottles. dark brown to black well decomposed crumbly The native vegetation was sedges, rushes, and in peat containing fragments of wood from Draco- places red tussock, flax, and swamp forest. The phy//um spp. and other woody plants resting on older soils are moderately leached and have a bluish grey gleyed silt. higher base saturation in the G horizon than in the topsoil. Clay increases down the profile, and 10. Southern from recent soils alluvium commonly iron does so in the B horizon. The Makarewa soils (92a), on the Southland Plains, younger soils resemble the Taitapu soils of the are derived from alluvial silts from Tertiary sedi- eastern region.

3 4 BIBLIOGRAPHY - -

(Soil reports pertinent to Chapter 3 are listed geographically for convenience of readers.)

A. NEW ZEALAND Soils and Agriculture of Matakaoa County. GIBBS, H. S. 1954. N.Z. Soil Bur. Bull. 11. 52 pp. Soils and Land Use. TAYLOR, N. H.; POHLEN, I. J.; ScoTT, Soils and Agriculture of Gisborne Plains. PULLAR, W. A. R. H. 1959. Pp. 28-33 and Maps 12 and 13 in ’A Descrip- 1962. N.Z. Soil Bur. Bull. 20. 90 pp. tive Atlas of New Zealand’. Govt. Printer, Wellington. Soils of the Gisborne-East Coast District and their Problems for Pastoral Use. Gises, H. S. 1959. Proc. N.Z. Grasst. Ass. 21: 9-19. B. NORTH ISLAND AND OUTLYING ISLANDS Soils and Agriculture of Wairoa Valley, Hawke’s Bay. PULLAR, W. A.; AYsoN, E. C. N.Z. Soil Bur. Rep. 2/1965. General Survey of the Soils of North Island, New Zealand. 35 pp. A Reconnaissance by the Staffs of the Soil Bureau, N.Z. Department of Scientific and Industrial Research, Soil Survey of the Heretaunga Plains. HUGHEs, H. A.; and of Extension Division, Department of Agriculture. HoDGSON, L.; HARRIs, A. C. 1939. Pp. 18-43 in Land 1954. N.Z. Soil Bur. Bull. 5. 286 pp. Utilisation Report of the Heretaunga Plains. N.Z. Dep. sci. industr. Res. Bull. 70. Soils of North Auckland. TAYLOR, N. H.; SUTHERLAND, Mid- C. F. 1953. Proc. N.Z. Grassl. Ass. 15: 3-16. Soils and Some Related Agricultural Aspects of Pl H7a6wke’s Ba LENNIZ. Is S.; ’Na S BBSBuH{ of NI rc eHAR 9S Sobis tdl lPp12 iin IRes and Country Planning Branch, Ministry of Works. 1964. Western GRANGE, L. I.; Govt. Printer, Wellington. Field-Work on Soils of Taranaki. TAYLOR, N. H. 1932. Annu. Rep. N.Z. Dep. sci. industr. Soils of Raoul (Sunday) Island, Kermadec Group. WRIGHT, Res. 1932-33, pp. 3-5. A. C. S.; METSON, A. J. 1959. N.Z. Soil Bur. Bull. 10. Soils and Agriculture of Oroua Downs, Taikoroa and Glen 49 Oroua Districts, Manawatu County. CowIE, J. D.; Soils of Little Barrier Island (Hauturu). WRIGHT, A. C. S. SurrH, B. A. J. 1958. N.Z. Soil. Bur. Bull. 16. 56 pp. 1961. 57-76 Little Barrier Island (Hauturu). N.Z. Pp. in Soils and Agriculture of Flock House, Bulls, Manawatu, Dep. Sci. industr. Res. Bull. 137. N.Z. COWIE, J. D.; HALL, A. D. N.Z. Soil Bur. Rep. Soils of the Inner Islands of Hauraki Gulf. TAYLOR, N. H. 1/1965. 58 pp. 1960. Proc. N.Z. Soc. 7: 27-9. ecol. Soils of the Manawatu-Rangitikei Sand Country. Soils of White Island. BAUMGART, I. L. 1959: Pp. 51-7 in COWIE, J. D.; FITZGERALD, P.; OwERS, W. 1967. N.Z. White Island. N.Z. Dep. Sci. industr. Res. Bull. 127. Soil Bur. Bull. 29. 57 pp. Soils and Agriculture of Kairanga County, Manawatu. Soils of the Waikato Basin. TAYLOR, N. H.; POHLEN, 1. J. COWIE, J. D. N.Z. Soil Bur. Bull. 31. (in prep.) 1958. Proc. N.Z. Soc. Soil Sci. 3: 4-10. Soils Wellington District. GIsas, H. S. 1960. Proc. N.Z. Soils and Agriculture of Part of Waipa County. GRANGE, of Soc. Soil Sci. 4: 4-12. L. I.; TAYLOR, N. H.; SUTHERLAND, C. F.; DIxoN, J. K.; HODGSON, L.; SEELYE, F. T.; KIDSON, E.; CRANWELL, Soils and Horticulture of the Greytown District, Wairarapa, Lucy M.; SMALLFIELD, P. W. 1939. N.Z. Dep. sci. industr. N.Z. COWIE, J. D.; MONEv, S. P. N.Z. Soil Bur. Rep. Res. Bull. 76. 85 pp. 5/1965. 36 pp. Soil Map of Whareama Catchment, Wairarapa, New Zea- Soils of the Bay of Plenty. GIses, H. S.; PULLAR, W. A. 1961. Proc. N.Z. Grassl. Ass. 23: 12-23. land. N.Z. Soil Bur. Map 4/1965.

Soils of the Rotorua District. BAUMGART, I. L. 1949. Proc. N.Z. Grassl. Ass. 11: 44-50. C. SOUTH ISLAND AND OUTLYING ISLANDS

Soils, Forestry and Agriculture of the Northern Part General Survey of the Soils of South Island, New Zealand. Kaingaroa Forest and the Galatea Basin. VUCETICH, C. G.; A Reconnaissance by the Staffs of Soil Bureau, N.Z. LEAMY, M. L.; POPPLEWELL, M. A.; URE, J.; TAYLOR, Department of Scientific Industrial Research, Farm C. R.; WILL, G. M.; Strrrow, J. A.; BLAKEMORE, L. C. Advisory Division, Department of Agriculture, and New 1960. N.Z. Soil Bur. Bull. 18. 51 pp. Zealand Forest Service (in prep.) N.Z. Soil Bur. Bull. 27. Soils and Geology of Some Hydrothermal Eruptions in the A Survey of Soils, Vegetation and Agriculture of the Eastern Waiotapu District. CROSs, D. 1963. N.Z. J. Geol. Geo- Hills, Waimea County, Nelson. RIGG, T.; CHITTENDEN, phys. 6: 70-87. E.; HODGSON, L. 1957. Cawthr. Inst. Bull. 42 pp.

87 3-4

Soils and Agriculture of Waimea County, New Zealand. Soils and Agriculture of Westland. Gises, H. S.; MERCER, CHITTENDEN, E.; HODGSON, L.; DoosoN, K. E. N.Z. A. D.; COLLIE, T. W. 1950. N.Z. Soil Bur. Bull. 2. 24 pp. Soil Bur. Bull. 30. 66 pp. Soil Survey of Westport District. HARRIs, A. C.; HARRIS, Soils of Stephens Island. WARD, W. T. 1961. N.Z.J. Sci. C. S. 1939. Dep. sci. industr. Res. Bull. 71. 27 pp. 4: 493-505. Soils and Land Use in the Upper Clutha Valley, Otago. Soils and Agriculture of Awatere, Kaikoura and Part of LEAMY, M. L. 1967. N.Z. Soil Bur. Bull. 28. 110 pp. MarlbS s55GIBBS, H. S.; BEGGs, J. P. 1953. Soil Erosion in the High Country of the South Island. r. Int D’ GIsas, H. S.; RAESIDE, J. D.; DixoN, J. K.; METSON, A. J. Soils Marlborough. GIBBS, H. S.; VUCETICH, C. G. 1962. of 1945. N.Z. Dep. sci. industr. Res. Bull. 92. 72 pp. Proc. N.Z. Grassl. Ass. 24: 8-17. Soils and Agriculture of the Alexandra District. McCRAW, Soils and Agriculture of Kowai County, Canterbury, New J. D. 1964. N.Z. Soil Bur. Bull. 24. 91 pp. Zealand. Fox, J. P.; GIBBS, H. S.; MILNE, R. A. N.Z. Soils of Ida Valley, Central Otago, N.Z. McCRAw, J. D. Soil Bur. Rep. 4/1964. 53 pp. N.Z. Soil Bur. Rep. 1/1966 (in press). 50 pp. Soil Survey Duvauchelle Bay Wainui District, of Banks Soils and Related Irrigation Problems of Part Maniototo - of Peninsula. C. S.; HARRIS, A. C. HARRIS, 1939. N.Z. Dep. Plains. RAESIDE, J. D.; CUTLER, E. J. B.; MILLER, R. B. sci. industr. Res. Bull. 65. 13 pp. 1966. N.Z. Soil Bur. Bull. 23. 68 pp. Soils Heathcote County, Canterbury, New Zealand. of Soils and Their Utilisation. Green Island -Kaitangata FITZGERALD, P. N.Z. Soil Bur. Rep. 2/1966. 32 pp- District. WRIGHT, A. C. S.; RICHARDs, J.; Loan, W. R.; Soils and Agriculture of Ellesmere County. WARD, W. T.; MILLER, R. B. 1952. N.Z. Soil Bur. Bull. 6. 36 pp. HARRIs, C. S.; SCHAPPER, H. P. 1964. N.Z. Soil Bur. Soils of the Lower Clutha Plains. CUTLER, E. J. B.; RICH- Bull. 21. 81 pp. ARDs, J. 1957. N.Z. Soil Bur. Bull. 15. 37 pp. Soils and Agriculture of Part Geraldine County. RAESIDE, The Soils of Southland and Their Potential Uses. CUTLER, J. D.; CAMERON, M.; MILLER, R. B. 1959. N.Z. Soil Bur. E. J. B. 1960. Proc. N.Z. Grassl. Ass. 22: 15-26. Bull. 13. 65 pp. Soils of South-West Fiordland. WRIGHT, A. C. S.; MILLER, B. 1952. Soil 31 pp. Soils of the Downs and Plains, Canterbury and North Otago, R. N.Z. Bur. Bull. 7. New Zealand. KEAR, B. S.; Gises, H. S., MILLER, R. B. Soils of Chatham Island (Rekohu). WRIGHT, A. C. S. 1959. 1967. N.Z. Soil Bur. Bull. 14. 92 pp. N.Z. Soil Bur. Bull. 19. 60 pp.

88 CHAPTER 4. SORS AND LAND USE

4-1* GENERAL PATTERN OF SORS AND LAND USE

by N. H. TAYLOR, I. J. POHLEN, and R. H. Scorr*

The overall pattern of New Zealand soils and quate for optimum plant growth (Fig. 4-1-3). the resulting land use may be best understood by The brown-grey earths are mostly sandy loams in grey considering the soils in three major divisions: texture with up to 6 in. of brownish topsoil places the zonal groups, which embrace the soils formed and with friable subsoil; but in many they on normal sites from ordinary siliceous rocks are stony and in others the subsoil is firm or and whose main differentiating characteristics are compact. Generally they are rich in plant nutrients due to processes controlled by the climate and and weakly acid to alkaline. Salty patches occur groups flats Central Otago vegetation of the zone; the intrazonal with on the of and accumulations distinguishing characteristics reflecting the strong of lime occur in the subsoils in places. The chief impress of some local factor such as a particular need is for more water, but irrigation must be kind of rock or closeness of the water table to the conducted with care in order to avoid the spreading surface; and the azonal groups whose characteris- of soluble salts in harmful concentrations and the tics are strongly modified by such causes as insta- waterlogging of the subsoils. Sheep farming for production bility or shortness of time during which the soil the of fine wools and store sheep is a has been developing. feature, but with irrigation fat lambs can be raised. Much lucerne is grown and in favoured ZONAL SOILS spots orchards of stone fruits, and brassica and other crops for seed. If the soils formed from unusual parent materials, yellow-grey (Pl. such as volcanic ash, and those occupying special The earths 7 and 8) occupy 31 sites, such as steep slopes and hollows, are set million acres of easy, and I million acres of aside, a simple zonal pattern is revealed. It con- hilly, country; they are the seasonally dry soils sists of the brown-grey earths of the semi-arid which are found in southern Otago, Canterbury, and nearly semi-arid areas, where rainfall is less Wairarapa, Hawke’s Bay, and Manawatu, where year than about 20 in, a year; the yellow-grey earths for approximately a third to a half of the of subhumid areas, where the rainfall is approxi- rainfall is inadequate for optimum plant growth mately 20-40 in, a year; yellow-brown soils (Fig. 4 1 3). They are formed on drift the - - typically young of the humid regions, where the rainfall is well deposits such as wind-borne dust and on distributed and is greater than approximately unconsolidated sediments. They include the transi- grassland drier 40 in, a year; and the associated podzolised soils tion from tussock to forest, the and podzols resulting from excessive leaching soils of the group, such as those found in Marl- beneath an acid surface litter of decomposing borough and parts of Canterbury, being formed vegetation. Fig. 4 1 1 and 4 1 2 show rela- under grassland, and moister ones, - - - - the tussock the tion between these groups. such as those in the Manawatu, formed under forest. The soils are characterised by greyish The brown-grey earths (Pl. 5) and associated brown weak-structured loamy topsoils, and pale solonetzic soils occupy 400,000 acres of easy’ brown to pale yellow nutty subsoils that are and 100,000 acres of hilly, country. They are flecked brown and grey. About 18 in, below the found typically in dry intermontane basins of surface, there is, in the older soils, a thick hard Central Otago and Mackenzie Plains, where the fragipan separated abruptly from the overlying for the greater part of the year rainfall is inade- horizons. Generally the soils are moderately acid, but in parts of Hawke’s Bay and northern Canter- fertile THE material used for section 4-1 has appeared in ’A Des- bury they are less acid and more than (Ed.), criptive Atlas of New Zealand’, A. H. McLintock elsewhere. The drier of these soils are used for 1959, but the figures for areas of soil groups are those calculated for ’An Encyclopaedia of New Zealand’, Govt. Printer, Wellington, 1966. *R. H. Scott, Department of Agriculture, Wellington.

89 4-1

Mixed forest with Kauri

Nort -brown earths

12"

Tussock grassland M xed podocarp forest - ,

Brown-grey Yellow-grey earths Southern and Centra yellow-brown earths earths M H X) M H X M H

Dairying and fat lambs

I

I Extensive Mixed Tall tussock grassland sheep farming arable farming I fat lambs Dairying fat lambs with irrigation and I C High country mixed yellow-brown earths arable farming

0 modal soils of the groups . X H a drier and moister soils linking with the modal soils 1 warmer soils average mean annual temperature 57. F approx. 4 C colder soils average mean annual temperature 420 approx. P podzolised soils under mor-forming trees

Extensive sheep farming

FIG. 4-1-1- Relation of main zonal soils of New Zealandto climate and native vegetation and to present land use.

In. 250

to 300 in

oF

45

3 ... 00 30

70

Annual Rainfay do

0

Southern Alps

6500

Alpinebarrens Mr Misery

5768 $ & O ford Hii ra

Suba pine ass ad

Sana a Schist Greywackc gravel dunes Morame Granies man ns ss on s

High unt o Yellow- own Podrolised steepland soils, alpine barrensate a rA s is

FIG. 4-1-2- Diagrammatic section from Hokitika to Waimakariri River mouth, showing soils in relation to parent rock, topography, vegetation, temperature, and rainfall.

90 4-1

per mixed arable farming and production of fat from li 2 ewes per acre to over 4 ewes acre, the - pasture be grown. lambs, but in the moister areas dairying is also and cereal and seed crops can practised, subsoil drains being used to assist the podzolised removal of excess water from above the pan. In Yellow-brown earths and their coun- in humid rainfall, the drier areas of Hawke’s Bay, Wairarapa, and terparts occur regions where the is for plant growth for Canterbury, white clover lasts only three to five on the average, adequate greater part year (Fig. 4-1-3), is years, but in the moister soils of areas such as the of the and Manawatu and southern Otago white clover is high enough to cause the iron compounds of the precipitated permanent when adequately topdressed. Shallow soil to decompose freely and to be it yellow pre- and stony soils related to the yellow-grey earths in the soil, staining a colour; these occupy some li million acres and cover much of cipitated iron compounds change the soil structure part, improve and drainage. These the Canterbury Plains; they are, for the most and soil aeration shallow over gravel and, where subsoil pans have soils, covering as they do a wide range of environ- irrigation. These give groups-the high country not developed, are well suited to ment, rise to three humid light soils are used for sheep farming, and with yellow-brown earths of the cold uplands of yellow-brown supplementary crops lambs can be fattened. Under South Island, the southern and central humid Southland irrigation the carrying capacity can be raised earths of the mild areas, such as

ALEXANDRA CHRISTCHURCH

7- - -7

6 - - - - 6

5 5

4

1111 | II IIII I I

(0) Brown-grey carth station (b) Yellow-grey earth station

111111111111 1111111111111

PAHIATUA HOKITIKA

Rainfall -*- 9

Potential evapotranspiration

7- 7

6 -6

5

45

(c) Yellow-brown earth station (d) Gley podzol station

FIG. 4-1-3- Relation, through the year, between average monthly rainfall and potential evapotranspiration for four representative climate stations.

91 4-1

and Wellington, and the northern yellow-brown acid, and light in texture, and the subsoils have earths of warmer North Auckland.* thin hard iron pans in places. These soils are being brought pasture for farming The high country yellow-brown earths (PI. 6) under sheep and grazing of cattle. cover 1 million acres of rolling and 1 million the Waterlogged counterparts of soils, acres of hilly country. They have developed under these the gley podzols or ’pakihi soils’ (Pl. 13 and 14), tussock at altitudes between 2,500 ft and 5,000 ft, cover I million acres of easy country and 100,000 and have dark brown, loose, loamy topsoils with acres of hilly country in Westland, where yellow, friable subsoils; they are moderately acid the rainfall is 100 in. or so per annum, and moisture and have low exchangeable calcium. They are used almost always much in excess of plant needs for extensive sheep farming-for production is the (Fig.4-1.3).Onthesesoilsthechiefproblemis of wool and some store sheep. On hillsides, one of drainage; water does not move fast enough where the plant cover is allowed to become thin, through the structureless soils to drain effectively frost-heave leads to soil erosion. Good results rain falls on In natural state have been obtained by oversowing the tussock the that them. the soils support good forest, but where pastures with clovers and topdressing with molyb- these the forest has been cleared and burnt resulting denised superphosphate. There is a good response the cover is all too often low scrub, rushes, and to sulphur. umbrella fern. There are no ready means of utilis- The southern and central yellow-brown earths ing the land once it has reached this condition. (Pl. 9 and 10) occupy li million acres of easy and The first thing to do, therefore, is to cease creating 4} million acres of hilly country. They have more of these wilderness areas until it is known formed under a forest cover and have loamy, how to use them. Attempts are now being made brown greyish brown with slightly to topsoils, to manage the forests without creating these heavier, nutty-structured, brownish-yellow subsoils. problems. Where forest consisted of much and the tawa The northern yellow-brown earths (PI. 11 and 12) associated fertility-demanding broadleaved trees, were formed under mixed forest in the warm it was relatively efficient at returning plant nutri- moist climate of North Auckland. They occupy surface leaf fall, and ents to the soil through the 4 million acres of easy and I million acres of hilly resultant soils are moderately fertile and only country. Under the warm moist climate, rocks moderately acid, low in phosphate. Where, though weather rapidly to form clays, which in turn however, forest consisted of much rimu or the become leached by the heavy rainfall, a process beech, less efficient at returning nutrients to trees that has been retarded or intensified according soil surface, soils are more strongly leached the the to the particular type of vegetation. Thus, the and lower in fertility. About 29o/o of rolling soils majority of the soils are warm heavy clays with and 17% of hilly soils of group are strongly the thin topsoils and subsoils of low fertility. Where leached. When sown pasture with lime and to the soils were formed under forest containing superphosphate (in places molybdenised), these much taraire or puriri the topsoils are brown and are used for dairymg and fattening of soils the granular, and the subsoils yellowish brown and lambs on rolling country. On more hilly land good the nutty; they are moderately acid but support are used for grazing sheep-for wool produc- they pastures when topdressed with lime and phosphate; for fat lambs. Cattle tion, store stock, and some in places molybdenised superphosphate is used. also run help control pasture growth and are to The rolling land is used for dairying and fattening prevent reversion of pasture scrub and to the to of lambs, the hills for grazing of sheep and cattle. fern. Where the soils were developed under forest con- The southern podzolised yellow-brown earths taining trees such as kauri and rimu in large and podzols are best developed in Southland, where numbers, they are of lower fertility; they have greyish they cover some 140,000 acres of easy and 200,000 typically brown topsoils with weakly granular yellowish acres of hilly country. They were formed under developed structures, and brown rimu-kamahi forest where trees, inefHeient at or greyish brown, harsh nutty or blocky subsoils; returning nutrients to the soil surface and with they are moderately to strongly acid and well acid litters, had remained long enough for the leached of plant nutrients; they support fair soil to be leached not only of its plant nutrients pastures when adequately topdressed with lime but also of its topsoil clay. The topsoils are grey, and superphosphate, and on the easier country many dairy and fat-lamb farms are situated. greater *The average of the mean annual temperatures for the high Because of the difficulty of topdressing, hsn and c n w ea the outherrn pastures on hill country are less easy main- oTr , the to t About 42% and 20% of approximate). tain. of the rolling the

92 4-1

dark, granu- billy land, occupied by the northern yellow-brown fertile and are characterised by deep, lenses earths, are of this very leached kind. lar topsoils; in the subhumid regions, of calcium carbonate are deposited in the subsoil. The northern podzolised yellow-brown earths and in- In the drier areas the easier land is used for podzols occupy J million acres of easy land and tensive arable farming, and the hills for grazing 300,000 acres of hilly land, mainly in North Auck- of sheep; poultry farming has become a feature land. Like their southern counterparts, they were on these soils near Oamaru owing to the favourable developed where inefficient at returning trees, climate and proximity of supplies of cereals grown nutrients soil surface and with acid litters to the In humid areas ’ on neighbouring soils. the the notably kauri and rimu, had remained long enough soils are mostly used for fattening or dairying. for the soil to be leached not only of its plant derived nutrients, but also of much of the topsoil clay. The yellow-brown sands are the soils Where they have developed under kauri, they are from coastal sand drifts of various ages; they known as ’gumlands’. The soils are characterised cover approximately 1 million acres. Much of the by thin grey structureless topsoils overlying a sand country is a complex of sandhills, which grey siliceous horizon. In places, especially where dry out excessively in summer, and sand plains, the soils are sandy, subsoil pans of humus and where ground water approaches or reaches the young iron are formed and impede the drainage. These surface in winter. On the soils where the soils are strongly acid and very low in plant sands are fixed by vegetation, subsoils are loose ground nutrients. Despite their unattractive appearance in and droughty except where water approach- have the natural state, they can be brought to support es the surface. On the older sandhills, which good dairy pastures, for soluble phosphates give been fixed by weathering, subsoils are loamy and a quick response once the acidity has been corrected retain moisture better. The drier soils, when sown by liming. The leaching of aluminium from the to pasture, are used for grazing; those with moister phosphate topsoil has reduced the phosphate-fixing capacity subsoils after being fertilised with and for dairying. of the soils. Where, however, pans have developed potash are used for sheep farming and is so far as to interfere with the drainage, the farm- Where the subsoil is loose and the vegetation ing of these lands is more difficult. In North sparse, blowing is a problem. Planting of sand- grass, places, pines Auckland there are about 130,000 acres of easy lupins and, in on the seaward protect and 30,000 acres of hilly country on which the fringe is needed to farmland. soils are sand podzols with strongly developed The yellow-brown pumice soils (Pl. 19) of central pans over large areas. Farming of soils these North Island occupy some 2 nullion acres of easy should be approached with caution. and 2 million acres of hilly country. They cover most of North Island within a radius of 50 miles INTRAZONAL AND AZONAL SOILS of Lake Taupo and extend northward to Bay of Plenty and eastward to near Gisborne, a large The intrazonal soils consist of rendzinas and part of being formed on material. from two related intergrades derived from calcareous rocks; them series of volcanic showers of pumice estimated yellow-brown sands of coastal districts; the the have fallen 800 and 1,700 years ago. The top- pumice North Island; to the soils of central the places brown soils in most are black to sands to yellow-brown loams of Waikato and Taranaki sandy loams; subsoils are pumice sands and gravels. derived from fine volcanic dust; the red and brown Wherever the climate is satisfactory and the texture loams and brown granular clays derived from is not so coarse as to render them droughty they basalt and andesite; gley or meadow soils of the may, with good strains of grass seed, phosphate low-lying areas where soils have been modified the manuring, and consolidation, be converted into by high ground water; and the organic or peaty good farmland, for where the pumice is soft and - bogs. The soils of the swamps and azonal soils is vesicular the soils retain more moisture than comprise recent soils from alluvium, the recent the usual for gravelly soils. For many years attempts soils from volcanic ash, and a large part of the to farm the pumice soils met with indifferent steepland soils and alpine barrens. success owing to bush sickness in sheep and cattle, Rendzinas and related intergrades occupy only but this ailment is now overcome by topdressing potash a small area and are grouped, for mapping pur- with cobaltised superphosphate. The re- poses, with associated soils. These associations serve in these soils is small; hence, with continued potash is occupy 120,000 acres in the subhumid areas-near use, topdressing with salts necessary. Oamaru, in north Canterbury, and in Hawke’s Much of the area of finer-textured soils has been being Bay-and 150,000 acres in the more humid areas- developed. Development is now undertaken mostly in North Auckland. The soils are highly on the more difficult areas of soils with coarser

93 4-1

textures. Considerable areas of the pumice soils of their high content of iron and aluminium the have been planted to exotic forests. Some of the red and brown loams and brown granular loams land planted could alternatively be used for dairy- and clays have a marked power to fix soluble ing or fattening, but, as in many other places, the phosphates in a form relatively unavailable to plants. best trees grow on the best agricultural land. The The sequence of fertility due to leaching, possibility of deterioration of these soils under in soil development sequences following age and pine forests is being closely watched. vegetation, which runs to greater or lesser extent all soil groups, is most marked in The yellow-brown loams (Pl. 15 and 16) are throughout the brown loams. The soils of high and moderate derived mostly from fine-textured volcanic ashes fertility occupy some I million acres of easy and erupted from volcanoes in central North Island ( million acres of hilly country. They carry good and from Mt. Egmont. They cover 4 million acres. pastures when maintained with dressings of super- These fine-textured ashes have been spread over phosphate and lime and, in addition, soils North Island from near Feilding and Napier in the from basalt respond potash. On easy land where south Auckland in north and, at one to the to the deep have been deepened by have given the soils are or the time or another, must rise to the soils removal of boulders, dairying and sheep farming over the greater part of North Island. In the centre for fat-lamb production is practised, and in places of Island have been overlain by the later the they for gardens gave pumice the soils are used market and orchards; volcanic showers that rise to the much of rolling land is used for fattening and soils. The yellow-brown loams have grey or brown, the grazing yellowish in conjunction with the neighbouring very friable, loamy topsoils; subsoils are hilly land. The soils of low natural fertility cover brown to brown, very friable, and on handling approximately 1 million acres and belong to two break down readily almost to a powder. The soils main classes-the strongly acid granular clays, are easily worked and grow good fodder crops. and moderately acid ironstone soils; where When adequately fertilised and consolidated they the soil moisture is satisfactory both of classes grow first-class pastures, which, on the easier these can be made carry fair pastures if slopes, are used for dairying and fat-lamb produc- to topdressed with lime, phosphate, and potash. On the acid tion, and on the hills for less intensive grazing. granular soils there is a marked response to Pastures respond well to superphosphate top- molybdenised superphosphate. dressing although absorption of soluble phosphate part is strong; lime responses are for the most The organic soils are peaty and are formed in slight to good. In these soils the reserve of available hollows and on low flats where the water table potash potash is low and increasing use of ferti- is permanently high and conditions lead to the lisers is to be expected. In the Waikato, the yellow- accumulation of organic matter. The area occupied brown loams, in effect, bring the light texture, by the organic soils is approximately I million good good drainage Auck- aeration, and of the southern acres, and they are mainly confined to the yellow-brown earths into the warmer climate of land district. Where the peats are mellow and growth the north; hence, the rapid spring of the fertile they can be farmed by methods used for production per pastures and the high acre of the gley soils, but the peats of acid bogs require Waikato district. special treatment; they can easily be spoiled by for once peat is allowed dry The red and brown loams* (Pl. 17 and 18) and over-drainage, to it breaks down a light porous mass brown granular loams and clays are formed from thoroughly to does not readily re-wet; at stage, fires basalts and from andesitic ash and andesites which this difficulty of farming. The main essentials respectively-rocks rich in iron and aluminium. add to the of farming seem to be careful levelling of the fields, They are often referred to collectively as ’volcanic applications of lime, phosphate, potash, and soils’. They cover 1) million acres. These soils, and in places copper sulphate, careful most of which occur in North Auckland and nitrogen, water and by stock Coromandel districts, are mostly friable clays control of the table, tramping surface. The full fruits of experi- (some almost loamy) with well developed struc- to consolidate the into methods of developing peat bogs tures; the soils on basalts are distinguished from ments the will not be attained until comprehensive schemes those on andesites and andesitic ash by their bog can be carried out. greater friability and lack of stickiness. Because covering each The gley soils owe their distinctive characteristics *The ’brown loams’ a describe use of as collective term to ground water at or near the surface for pro- the yellow-brown loams, red and brown loams, and brown to periods during year. This granular loams and clays, has been abandoned to avoid longed the causes the confusion. Red and brown loams are separated by their formation of a grey subsoil commonly mottled dominant field colours. In earlier publications the soils colours. They occupy ( million acres, now named brown loams were called mid-brown loams. with rust

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the greater part lying in the Auckland district. juvenated by erosion. Consequently, when the They need draining before they can be satis- plant cover is interfered with by man, the erosion factorily farmed, but when drained can be made is accelerated, the results of this being obvious to support good pastures for dairying and fatten- not only on the hillsides themselves but also in ing; these soils, especially where they are heavy the rivers and on the river flats. poach In texture, easily, and are readily invaded Of the steepland soils, those of the semi-arid by rushes and buttercups. zone (steepland brown-grey earths) occupy some ( million acres. On slopes depletion of The recent soils from alluvium cover approxi- these the cover swiftly followed European occupa- mately 2 million acres of alluvial flats where, in tussock and problem of re-establishing a cover the not-long-distant past, river sediments have tion, the of vegetation is difficult indeed. been added soils from For to the time to time. yellow- part, yellow The subhumid steepland soils (steepland the most they are deep, brown to grey earths) occupy 21 million acres; for the most loams with scarcely any differentiated topsoil part lie east of more humid high where the accumulation is rapid, or with a deep, they to the the country steepland yellow-brown earths, which occupy dark granular topsoil where accumulation is slow. some 4} million acres of cold, high country on Where drainage is poor, as on the low-lying flats, the eastern side of Southern Alps. Both of many of the subsoils are grey and mottled. Sandy the the these soils are are used for and gravelly types with excessive drainage are tussock-covered, extensive grazing, and present similar problems. scattered throughout New Zealand, but they The use of fire in past, and over-grazing by cover a much smaller area than do the more the rabbits and sheep have led steady deteriora- fertile loamy soils. Where the fertile soils are on to the tion of much of this country. With the baring of broad flats, and measures have been taken to protect ground between the tussocks, sheet and wind them from flooding, they rank amongst the erosion have place and has been a the most highly productive soils for either crops taken there speeding up of creep of mantle of rock or pastures. These soils are mainly used for fat- the the waste, resulting in formation of new shingle lamb production and for dairying. In the drier the in pasture slides and an increase area of old ones. On the areas, they are also used for cereals, and higher country process is assisted by vegetable seed crops, pulse crops for canning, this the pulverising action of frost on bare ground. pip and stone fruits, small fruits, and, particularly the the As a result more waste is supplied rivers, in the Motueka district, for tobacco. to the and the aggrading parts of the valleys tend to The recent soils from volcanic ash (Pl. 20) whose build up more speedily than before. On these area is approximately ) million acres, include those and associated soils are situated the large sheep accumulating in circular area of about a roughly stations stocked with merino sheep for the produc- 20 miles in radius around active volcanoes the tion of fine wool. Ngauruhoe and Ruapehu; also included are the Steepland yellow-brown soils on the material ejected from Mount Tara- soils of the mild and New Zealand 121 wera and Lake Rotomahana in 1886, and on warmer areas of occupy some They in material from other small recent eruptions. Where million acres.* were originally covered forest Of 2 million acres are they cover the pumice soils, these deposits are and scrub. this area, derived from yield high agriculturally important as their cobalt content is rocks that soils of natural fertility; greater part of forest high enough to correct the deficiency associated over the these the has been felled pasture has been Here, with the underlying pumice. and sown. problems too, of instability have to be overcome, The soils of the steep lands occupy approximately for in places slips and slumps cause trouble, al- half of the area of New Zealand, being most though by and large the slips over fertile soft extensive on axial ranges, large areas the though rocks heal rapidly and new soils are soon formed. also occur in north-west Nelson and east Taranaki. This land is used for sheep farming mainly for They form intimate and complex patterns of weakly the production of wool and store sheep, and it is developed soils on unstable slopes with more from these areas that the fat-lamb farmer on easy strongly developed soils on the more stable slopes. country obtains a large proportion of his flock Although these soils show certain characteristics replacements each year. The remaining 101 million related to the zone in which they are formed, they are for the most part shallow, and the subsoils *This estimate meludes. areas (mostly small) of steep land in fertility vary widely according to the nature of covered wholly or in part by volcanic ash or other volcanic the underlying rocks. Because of the steepness material-the soils shown separately on the maps as steep- land soils related yellow-brown pumice soils, red and of slopes soils are relatively unstable and to the these brown loams and brown granular clays, and recent soils even under natural conditions are periodically re- from volcanic ash.

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per acres are occupied by soils derived from rocks formed under a rainfall greater than 100 in. places iron pans below naturally low in plant nutrients; the maintenance annum and in have thin in of grass cover depends upon topdressing and a the gleyed horizons. They are largely subalpine rigid control of grazing. On such soils, land bared scrub and tussock, and are subject to debris by slips and other forms of erosion is slow to avalanches. cover. Aerial and aerial aids fencing topdressing to The barrens some 3} million great alpine occupy have opened the way to better farming of a acres of land at high elevations where vegetation deal of land, but much of it must be retained this is or absent, and include much bare rock protec- sparse in forest for the control of rivers and the and ice. Raw coastal sands occupy ( million acres. tion of the lower country. Many are surprised that the steepland soils From foregoing, relation between the well and can the the should respond so to topdressing its soil and the factors that control formation be made to produce abundant feed, but, apart becomes abundantly clear. Where parent-rock from a general tendency to be shallow and so to is materials are of normal siliceous composition, be subject to summer drought, there nothing where the land surface is subdued and uncompli- fundamentally wrong with the fertility of the cated by problems of ground water, and where steepland soils. Actually most of them have a sufficient for soil formation has elapsed, the higher natural fertility than their counterparts on time resulting soils follow a fairly simple pattern in easier slopes. It is problems arising from the angle accordance with the local climate and vegetation. of slope itself that limit farming-problems of The colder and drier the climate, the less weathered instability, the physical difficulties of topdressing, is soil skeleton; the higher the rainfall, the fencing, controlling grazing, and making adequate the more completely soluble plant nutrients and provision for supplementary feed. the other compounds tend to be washed from the Steepland podzolised soils occur mainly in is soil; and the state of the soil at any one time Nelson, Westland, and western South- by western strongly conditioned by processes controlled land; occupy 6) million acres. These infertile life. they the vegetative cover and associated soil in forest so. soils are largely and should remain Further complexity in the soil pattern is due to be This does not mean that the area should parent rocks of widely divergent composition, to for dying of position written off and neglected, the recent differences in topography and the of forest possibly of the rata over a million acres the ground water, to lack of time for strong soil Westland indicates pro- mountain sides of that development, and in places to outstanding charac- found changes, probably induced by deer, opossum, during periods teristics acquired earlier when the disease, place forests. and are taking within these soil environment was very different from that of Any of vegetative cover on weakening the the today. possibly have conse- mountain sides could serious The environmental factors that control soil quences for lowlands of the occupiers of the formation also tend to govern the kinds of land Westland. use. Thus the close relation between soils and the problems kinds land in ways Subalpine steepland gley soils and gley podzols and of use arises two internal characteristics of soils together with their hilly and rolling counterparts -from the the from factors such as occupy 3) million acres in western Southland, themselves and external besides Westland, and western Nelson. They occur at climate and topography, which, strongly ft in influencing formation of soil, also directly elevations above approximately 3,000 the the the influence it for his various south and 5,000 ft in the north and extend up to the way man uses part purposes. the alpine barrens. For the most they are

4-2- FORESTRY

by A. L. POOLE, Director-General of Forests, New Zealand Forest Service

part NEW ZEALAND AS A introduced, not to be matched in any other TREE-GROWING COUNTRY of the world comparable in size. The native trees grow in forests covered, in the New Zealand is a tree-growing country of themselves that over of outstanding excellence. In it can be found growing country’s virgin condition, two-thirds the both land area. They range from the well known kauri thriftily a range of forest trees, native and

96 PLATE 5. Fruit growmg and irrigated sheep pasture on ter- races of the Clutha River. near Cromwell, Central Otago. Steep schist hills in back- ground hate been used for extensive sheep grating but de- pletion grass- of natile tussock land has allowed setere wind and sheet crosion. Soils are brown-grey earths, with Linn- burn-Molyneux soils on ter- race lands and Alciandra soils on the hills.

Photo, R. Julian

PLATE 6. TUSsock grassland on high-country sheep run in mountainous regions of South Island. Soils are high country yellow-brown earths used mainly for extensive sheep grazing and production of fine wool. On small areas of flatter land (Cass soils), grass-clover pastures have been established by oversowing and topdress- ing. These are then used for breeding sheep as well as for some fattening.

Photo, National Publicity Studios PLATE 7. A southern yellow- grey earth (Timaru silt loam) from Oamaru district, North Otago. The gradual changes of soil structure from the top- down soil to the massive hard fragipan lying below 24 in, are illustrated in this proile.

Photo,’E. J."B. Cutler

Photo, National Publicity Studior

PLATE 8. Downlands of South Canterbury used for cereal cropping or for pastures in the breeding and fattening of sheep. Soils are southern yellow-grey earths (Timaru soils) formed from loess under a subhumid climate. PLATE 11. A northern yellow- brown earth (Waikare clay loam) from Kaipara district, pro- North Auckland. In this tile the shallow topsoil and the coarse nutty to prismatic structure in the subsoil are shown. Unweathered rock is more than 10 feet below the surface.

Photo II. S. Gibby

Photo, IL S. Giblo PLATE 12. Rolling to hilly land near Wellsford, North Auckland. Soils yellow-brown deeply are northern earths developed from weathered claystones under kauri forest. Topdressing and grazing careful management are needed to check growth of manuka and native shrubs. Pt 9. A central yellow- ent brown earth (Korokoro silt loam) from Johnsonv ille dis- trict, Wellington. The profile shows the strongly deletoped nutty structure and indistinct horizons of this soil.

Pluno, 4. P. ( nderhill

Photo. A. P. Underhill PLAu 10. Rolling, hilly and steep pastoral land near Wellington. Soils are central yellow-brown earths developed from greywacke materials under podocarp-broadlealed forest. Pastures on rolling land (Judgeford soils) are used for dairying or sheep fattening, and those on hilly and steep land (Korokoro and Makara soils) for store sheep and cattle. Soil erosion under pastoral use is negligible. PLA TE 13. A deep southern gley podzol (Okarito peaty loam) from Hokitika, West- land. The profile shows the deep humic topsoil over the structureless silty subsoil through which drainage is extremely slow.

Photo. H. S. Gibbs

Phoin, LZ. Fore Service.by J. H. Johny, A.R.P.S. st PLATE 14. Pakibi land, Westland, after remoral of the native forest for pastoral use. Soils are gley podzols growing rushes, sedges, ferns and mosses at present but they could be developed for forestry. PL ATE 15. A yellow-brown loam (Eg- mont brown loam) from Auroa, South Taranaki. This soil is a deep friable and finely granular loam derived from vol- 4%\ canic ash. Its drainage is excellent.

Pharo, K. S. Birrell

Pt ATE 16. Dairy farm on yellow-brown loam formed from volcanic ash deposited on ring plain around Mt Egmont, Taranaki. All the land outside the National Park Forest on the slopes of Mt Egmont has been cleared of forest, sown with grasses and clovers and topdressed with phosphate and potash. With this management the land allows highly productive pastoral use.

Photo, National Publicity Studios PLATE 19. Dairy farm and conifer forest on yellow-brown pumice soils (Taupo soils) near Rotorua. After burning or crushing the native scrub and fern, pastoral grasses and clovers are established using heavy applications (9cwt) of superphosphate in the first year and subsequent annual treatments with phosphate and potash. Cobalt is needed healthy to maintain stock. Large areas of the hilly and higher pumice soils have been planted with exotic conifer forests which begin to provide timber supplies within 20 years of planting.

Photo U. Cr s

PLATE 20. Tussock grassland and shrubs on the high plateau around Mts Ngauruhoe and Tongariro, Mt Ngauruhoe erupts intermittently and the accumulated deposits of vol- canic ash over the plateau are formed into recent soils from volcanic ash. The land shown in this view is included in Tongarico National Park.

avoonal Publicity Studi ’ PL.ATE IT. A red loam (Waimate North clay loam) from Kerikeri district, North Auckland. This soil is a deep friable granular to nutty clay derived from basalt. The drainage is fairly rapid and may cause moisture shortage in dry periods.

Photo. R. Julian

PLATE 18. Baby farming On rolling land near Whangarci, North Auckland. Soils are red loams derived from basalt scoria and la\a under broad- leaved forest remnants of which occur in background. Note the fences built of basalt rocks. ,4

Photo. 4 J. Mason 4-2

pine pine (P. (Agathis australis), which throughout the north the Scots (P. silvestris), Corsican poplars, grows to giant dimensions and which belongs to nigra), ashes, oaks, willows, and many from Australia. The a genus that has a dozen or more representatives species of Eucalyptus story in Queensland, New Guinea, and some Pacif ic of these introductions is one of many successes. Islands, to the southern beeches (Nothofagus spp.), Thus New Zealand has an extensive range of introduced from which are thought to have affinities with ancient native and trees which to select southern vegetation. In between these are a host in order that trees and forests may take their place of other trees. Some are adapted to deep silty rightful in complete and correct land use. swamps, in particular the kahikatea (Podocarpus Native forests as protection forest on hills and dacrydioides) growing gregariously in dense stands mountains and as commercial forests on easier and to heights of more than 150 ft. There are terrain (where they must remain because the soils in many members of the Podocarpaceae of both the are difficult for agriculture), and exotic trees genera Podocarpus and Dacrydium. Rimu (Dacrydi- extensive forests and in farm woodlots and shelter land um cupressinum) is a dominant tree throughout belts, all form important components of use; promises grow most forests up to altitudes of 1,500 to 2,000 ft an importance that to materially particular but is abundant and forms dense stands in two as time goes on. Exotic forests in are primary main areas only-throughout North Auckland beginning to form a diversification of production. forests, where the climate is warm, and in West Coast forests, where the climate is very wet. There are many hardwood species, some spread almost MOUNTAINOUS AREAS throughout the length and breadth of New Zealand. The most widespread of all is probably the kamahi Native forests now cover about 220/o of the (Weinmannia racemosa) and the northern and land surface. Their stronghold is along the steep southern ratas (Metrosideros spp.). The former mountain chains, where at least four-fifths of this for commences life mainly as an epiphyte on tall percentage is found. Here they are vital exer- forest trees. The latter grow on the most in- cising some control of the mountain torrents and hospitable of soils. Akeake (Dodonaea viscosa) for preventing erosion of the steepland soils under be grows to a small tree in coastal forests. The same the harsh mountain climate. This seems to parts for tree grows in the mountains in India and in Africa- more severe than in most of the world Amongst the monocotyledons one of the few the tree line is limited to a mean maximum alti- tree members to be found anywhere, the cabbage tude of about 4,500 ft in the mountains to the grows dimen- ft in tree (Cordyline australis), to large north and descends to 1,500 to 2,000 the sions and is present throughout New Zealand south. At similar latitudes in Europe or North forest and scrub in damp situations. Fuchsia has America the tree line is often 2,000 ft higher. Ameri- frosts a tree member, even though this is a South In the New Zealand mountains severe and can genus represented in New Zealand by three or high winds throughout the year limit tree growth. four species only. Another genus, Coprosma, con- Moreover, when vegetation is destroyed on steep sisting mostly of shrubs, has two or three species slopes at high altitudes, these climatic features reaching tree dimensions. The same applies to cause erosion of the already unstable steepland plants, parent the genus of heath-like Dracophyllum- soils and also start erosion of the rocks. beds The Maori introduced no trees but cultivated Aggradation in the of the mountain torrents feed quickly follows. artificially at least one native tree, the karaka and the rivers into which they (Corynocarpus laevigatus), for the food value of Excessive browsing by introduced wild animals inside forests. Thus the berries. Europeans, on the other hand, in a also starts erosion these on great Southern Alps century and a quarter have introduced a the steep western flanks of the the deer many trees. Their coming coincided with wide- ground-browsing of the European red and spread activity in plant exploration, particularly chamois combined with the tree-top-browsing of in North America. Trees from these introductions the Australian opossum lead to a loosening of glacial held found their way to New Zealand almost as soon perched shingles. These are on the by forest. Once as to the European countries sponsoring the ex- mountain slopes only the they fir, (see Chap- plorations. In this way Pinus radiata, Douglas slip, a severe erosion cycle commences browsing Cupressus spp., western red cedar (Thuya plicata), ter 5). A similar combination of animals Pinus ponderosa, P. murrayana, P. strobus, and is, in many places, destroying forest on steep many others, all from North America, arrived here slopes, profitable protection forest in good to become the basis of a highly exotic The retention of condi- great Nevertheless forest industry. Colonists also brought with them tion is therefore of importance. both been the trees from their own homelands. These were it has, wittingly and unwittingly, cleared

97

0 4-2 and burned off some mountain slopes with the fastest growth rates of any coniferous forests in inevitable consequences of severe erosion. Many the world. Although these soils are excellent soil conservation measures have been undertaken agricultural soils, forests will undoubtedly remain to reverse this process, more particularly on farms on them because of the large industrial capital on fertile steepland soils related to zonal yellow- investment depending on wood and because of brown earths derived from soft Tertiary rocks. the important effect the industrial produce has These soils, when waterlogged, slip along the upon the country’s economy. As the industry contact with the parent rock, or, if this is shattered grows, in fact, good pastoral land-yellow-brown poplars, and clayey, slump badly. Willows, and pumice soils-is being encroached upon to grow other trees are planted on such slipping and forest for pulpwood. This development can be slumping country. If the soils are not fertile expected to continue for some time. enough to allow this to be done economically, a All other exotic forests have been established whole catchment may be retired. This happens on in much smaller units than those on the yellow- steepland soils related to yellow-grey earths, which brown pumice soils. They have been planted on in places dry out severely at some seasons. A low a variety of soils, from moist yellow-brown earths growth of shrubs and trees, particularly the tea to droughty yellow-grey earths, and with a range trees (Leptospermum spp.), which are pioneering of species. At the time of planting or acquisition species, can then be established to take charge of the land for planting, it was usually just marginal quickly and halt the erosion. Economically a to economic agriculture sometimes because of better use of this land would be to plant it with steepness, sometimes because of difficult soils. As an exotic tree crop that would stand droughty agriculture has developed and expanded, however, conditions. On the less fertile soils in dry moun- these soils have mostly become economic agricul- tains and at high altitudes this quick reversion to tural soils. Sometimes fast-growing trees have been native shrubs and trees does not take place. planted extensively to control gorse (Ulex europeus) However, some introduced trees can be estab- or other noxious weeds on country where agricul- lished. Trees like Pinus ponderosa and P. murrayana tural implements cannot deal with them. will grow and the latter reproduces itself readily. Two groups of soils only, present any real growing These trees, once established, can act as nurses to difficulties in exotic forest trees on them. the incoming native vegetation. Under more The first are those in north Auckland that form favourable conditions along the lower slopes on a sequence of yellow-brown earths in various the eastern side of the South Island mountains, stages of degeneration by podzolisation under on soils that are steepland intergrades between kauri forest. By a judicious selection of species, yellow-brown yellow-grey and earths, there is however, it is possible to establish exotic forests little doubt that exotic trees will eventually be on them. Species that can be used for the most used to correct excessive erosion and at the same difficult soils are some of the North American time form extensive commercial forests. southern pines and the European maritime pine (P. pinaster); P. radiata, which hitherto has been difficult grow, now succeeds on some soils AND AREAS to LOWLAND MONTANE provided phosphate. they are fertilised with- Exotic afforestation was begun in a modest way The other difficult soils are the very wet gley podzols grow about the beginning of this century. The object of Westland. These excellent in- was to grow a sustained yield of forest produce digenous rimu forest, which is destroyed in the process logging. Following destruction, to take the place of commercial indigenous timber of this flat become boggy, that was being cleared for farming or would not the soils on the country and reproduce itself readily once cut out. Exotic on sloping country become rapidly covered with growth, forests were planted most extensively from 1925 to shrub and fern which defeats any attempt 1935 on the yellow-brown pumice soils about the to establish grass. The establishment of exotic middle of the North Island. That decade was im- trees under these conditions requires the use of mediately before the discovery of the trace element special techniques, including the use of fertilisers, cobalt as a cure for stock sickness on some of and selected species, these pumice soils. The application of cobalt In general the best exotic forests have been revolutionised land use. For a time afforestation established on the stony yellow-brown earths and almost ceased in favour of large-scale land develop- adjacent soils derived from the Nelson Moutere ment for farming. It is upon the half million acres Gravels. Yellow-brown earths along the eastern of exotic forest, mainly Pinus radiata, established flanks of the Southern Alps also grow excellent on these soils that the large pulp and paper industry exotic forests. There, however, they suffer some has been founded. Growth rates are probably the damage from wind, snow, and hail.

98 4*3

Farming in New Zealand occupies 44 million block river channels. Other willows sometimes acres (this area includes 20 million acres of culti- form thickets, many acres in extent, on peats. vated farmland), mostly won by clearance of forest Extreme fluctuations of the water table in low- gleyed or shrub land; a clearance that has been almost lying soils seem to be the reason why complete except for reserves. A proportion of coniferous trees will not grow well. The same this land, because of steepness, erosion, or growth fluctuations in yellow-grey and yellow-brown of noxious weeds, is more suited to trees than to earths lead to the killing of coniferous trees by pastures or other crops. Farmers frequently the root-attacking fungus Phytophthora. Well establish woodlots of exotic trees and also shelter drained soils however, grow a good range of belts along boundaries. They have, in fact, the softwoods, the only limitation being dryness. On most favourable conditions-the best soils and the brown-grey earths of the low-rainfall district, climates and proximity to markets-for commercial Central Otago, exotic trees can be established tree growing throughout the country. As time only with considerable difficulty, but once estab- ponderosa goes on therefore, farm forestry is bound to be an lished, species like Pinus nigra and P. increasing enterprise. are successful. On the yellow-grey earths of the Farming soils do not often impose severe eastern side of South Island where annual rainfalls limitations on the choice of suitable trees for are only 20 to 25 in., the radiata pine can be shelter belts and woodlots. Paradoxically, the established but grows at only about half the rate most difficult are the richest, low-lying recent that it shows in moister climates. On the Canter- soils derived from alluvium; gleyed soils also bury Plains, wind, not poor soil, is its main have drawbacks. These groups of soils will not deterrent. par- support thrifty coniferous trees, which are the Along the west coast of North Island in most important trees for shelter and woodlots; ticular, soils of sand dunes that were fixed by but they will grow some broadleaved trees well, vegetation have been turned to moving wind- grazing especially poplars, provided the climate is not blown sand by stock. With certain tech- planting grass, subject to strong winds. Many northern hemi- niques, such as with marram these sphere trees however, including the English oak, sands can be fixed again. They are then eminently growing pine, half are limited, not by soils, but by susceptibility to suited for radiata and a mile insect damage and diseases. Along silty river and or so to the leeward of the coast commercial stream banks, willows, mainly the crack willow stands of this tree can be established. These (Salix fragilis and S. babylonica), have found an sands will eventually support extensive radiata ideal home. They grow luxuriantly and often pine forest.

4-3* THE GROWTH OF RYEGRASS AND WHITE CLOVER ON UNTOPDRESSED SORS UNDER GLASSHOUSE CONDITIONS

by J. P. WIDDOWSON and N. WELLS

INTRODUCTION plants of certified white clover of strain C 1732 (Grasslands Division, Department of Scientific The growth of perennial ryegrass (Lolium and Industrial Research) were grown separately perenne) and of white clover (Trifolium repens) on in plastic pots during autumn 1962 in an unheated 54 soils is here considered in relation to the glasshouse at Soil Bureau, Taita (mean daily classification of New Zealand soils (Chapter 2). maximum 720F, mean daily minimum The plants were grown in pots of untopdressed temperature All glasshouse 540F, with extremes of 780? and 460F). white topsoils maintained under conditions plant growth, clover plants were inoculated with an effective to illustrate the effects of soils on strain of rhizobium N.Z.P.I. (Plant Diseases independent of the factors associated with their Division, Department of Scientific and Industrial climatic environment. Soils for these pot trials Research) after emergence of first leaf. were subsamples of those collected for the assess- the Photographs of seven-week-old ryegrass ment of physical and chemical data recorded in the plants (Plates 21 24) and of white Chapter 11 and had been stored in their moist to ten-week-old polythene clover plants (Plates 25 to 28) have been arranged field state in bags at room temperature. according soil classification. The main soil Samples of the A horizons (free of stones) were to the have been figure maintained in pots between 500/o available moisture units arranged across the accord- development (usually capacity and field capacity. Nine plants of certified ing to their degree of soil perennial ryegrass of strain A 2272, and nine increasing with soil leaching). Intergrades in the

99 classification have also been included in some of from loess, recent soil from alluvium, recent soils pots granular the leaching sequences. The of soil in the from volcanic ash, steepland brown greatest photographs were labelled with the laboratory clay from doleritic rocks). The amount number (in Chapter 11-2) and the weight of the of growth occurred on the Rotomahana soil pot for maintenance of moisture conditions. (recent soil derived from muddy ash). Other soils Two cuts of ryegrass and one of white clover giving large amounts of growth were Temuka were taken during the ten-week growth period. (southern gley soil) and Barrhill (southern recent Plants were cut at a height of half an inch above soil from loess). Poor growth occurred on Ngauru- the soil surface and were oven-dried. The dry hoe soil (recent soil from andesitic ash), Otano- weights of ryegrass and white clover produced momo soil (organic soil) and Te Kie (steepland after ten weeks are presented in Table 4*3-1; brown granular clay). these values do not represent the potential produc- capacity of soils as fertilisers have not tive the WHITE CLOVER been applied. Plate 25 shows white clover plants grown on zonal soils in natural state are moisture- RYEGRASS that their deficient. Brown-grey earths are deficient for Plate 21 shows ryegrass plants grown on zonal most of the year but under glasshouse conditions produced good soils that in their natural state are moisture deficient. with sufficient moisture they yellow-grey Brown-grey earths are deficient for most of the growth. Within the earths that are year while yellow-grey earths and associated moisture-deficient for about half the year, the shallow soils are lacking in moisture for about weakly leached Cluden soil grew an amount of half the year (see Chapter 2-7). Under glasshouse white clover similar to that produced by the brown- yellow-grey conditions all these soils gave good growth except grey earths. The moderately leached Matapiro which contained glassy minerals asso- earths and related shallow soils gave poor growth growth ciated with volcanic ash in the topsoil. It will be of white clover in comparison with their shown later that plant growth was generally poorer of ryegrass (Plate 21). grown on intrazonal soils derived from volcanic ash. Plate 26 shows the white clover on zonal growth Plate 22 illustrates the on the zonal soils having adequate or surplus moisture through- year. yellow-brown soils that usually have adequate or surplus moisture out the These are earths and throughout the year. These are the yellow-brown podzols. An increase in soil leaching resulted in grown. earths and podzols. Increasing leaching had an a decrease in the amount of white clover adverse influence on the growth of ryegrass but The weakly leached soils Puhoi and Mangaweka weakly leached members gave yields of ryegrass gave more growth than the moderately leached that were similar to those obtained from the yellow-grey earths. The very strongly leached gave growth yellow-grey earths developed under lower rainfalls. podzols (pH H,O 4-1 to 4-6) values The podzols (pH H20 4*1 to 4-6) gave very little that were less than one hundredth of those of the growth, the values being about a twentieth of weakly leached brown-grey earths. growth those from the brown-grey and yellow-grey earths. Plate 27 illustrates the of white clover on Plate 23 shows the growth of ryegrass on intrazonal soils derived from volcanic rocks or ash: intrazonal soils derived from volcanic rocks yellow-brown pumice soils from rhyolitic ash, (mostly ash), yellow-brown pumice soils from yellow-brown loams from andesitic and rhyolitic rhyolitic ash, yellow-brown loams from ande- ashes, brown granular loams and clays from old sitic and mixed ash, brown granular loams andesitic ash and from andesitic massive rocks, and clays from old andesitic ash and from ande- and red and brown loams from basalt scoria and sitic massive rocks, and red and brown loams lava flows. An increasing degree of soil leaching from basalt scoria and lava flows. The growth within soil groups gave a general decrease in the produced, growth of ryegrass on these soils was generally poor when amount of white clover and the compared with zonal soils (Plate 22) at similar on the strongly leached member was usually about stages of leaching, except at the stage of very a tenth of that on the moderately leached member. strong leaching where growth was equally poor. The Hamilton and Taupo soils were collected pastures The amounts of growth decreased with increasing close to topdressed and may have received stage of soil leaching and the least growth occurred incidental increments of fertiliser over a number in the Kaingaroa soil (pH H,O 4-0). of years. growth Plate 24 illustrates the growth of ryegrass on Plate 28 shows the of white clover on gley the remaining intrazonal soils (gley soils and the remaining intrazonal soils (rendzinas, organic soils) and on the azonal soils (recent soil soils, and organic soil) as well as on the azonal

100 4-3 soils (recent soil from loess, recent soil from indicate a humus that is low in ligno-protein, alluvium, recent soils from volcanic ash and steep- high in cellulose, and usually low in bases. The land brown granular clay). The most growth 10 highest values for the growth of ryegrass occurred on the Waiareka soil (nigrescent southern were from soils having a C/N ratio that ranged brown granular clay) and was followed in this from 18 to 11 and averaged 14, while the 10 respect by the Rotomahana soil (recent soil from poorest values for growth were from soils that muddy volcanic ash), both of these soils being ranged in C/N ratio from 86 to 17 and averaged 32. growth very weakly leached. The poorest was The ryegrass was cut in two stages, the first from the strongly leached Ngauruhoe soil (recent being at the time of the photographs (7 weeks) and soil from volcanic ash). the second being after a further 3 weeks. The second cut of ryegrass was on average 50% of the first cut. Ten soils from volcanic ash, however, gave PLANT GROWTH IN RELATION TO a second cut was on average 100% of SOIL CHEMISTRY that the first cut. This would suggest a slow but persistent Four soils, Rotomahana (recent soil from muddy breakdown of organic matter to release available in Soils in volcanic ash), Temuka (gley soil), Cluden (yellow- nutrients, such as nitrogen, these soils. grey earth) and Waiareka (nigrescent southern which the second cut was very much below the brown granular clay), each gave a combined first cut (average only 20% of first cut) were podzols (Okarito, Tautuku, One Tree Point) weight of ryegrass and white clover that was over and in initial growth 2 g; this was equivalent to at least a hundred which the amount of was very low, brown-grey (Lowburn Conroy) times the growth obtained from the poorer soils. and earths and growth The ratio of ryegrass growth to white clover in which the initial amount of was very growth varied from 1 to 76. Soils that gave a high high. ratio were Tutamoe, Puketeraki, Belmont, Marton, Timaru, and Waikare. It is probable in most that GROWTH VALUES IN RELATION TO of soils showing a high ratio, growth these the SITE VEGETATION of white clover was restricted by molybdenum pot deficiency in addition to a low level of phosphorus. In the trial the litter layers, because of their Soils having a low pH produced little growth transient nature, were discarded in favour of the of white clover. The 10 soils with the least amounts first mineral horizon. For the Tautuku soil de- of growth had pH H20 levels ranging from 5-3 veloped under kamahi forest a comparison was to 4-0 and averaging 4-5, whereas the soils with made between ryegrass and white clover grown the most growth had pH H,O levels ranging from in the deep decomposed litter (OS horizon, 14-2 in.) horizon 5-5 to 7-0 and averaging 6-0. The 10 soils with and on the underlying mineral (A29 most ryegrass growth had an average topsoil 0-2 in.). The plants grown on the On litter pH H,O of 5-3; this value was lower than that horizon alone were only 5% greater in amount of gave growth growth for soils that the high values for than those on the As mineral horizon white clover, and the difference was not sufficient to influence The growth of ryegrass would have been strongly conclusions drawn from Table 4 3 1. On the - - influenced by the nitrogen availability of the soils the other hand the thin, relatively undecomposed in addition to their phosphorus status. The nitro- litter (Oz horizon, 1-0 in.) of the Kaingaroa soil gen status of a soil is not easy to assess in a produced much better growth of ryegrass than laboratory, and the only measurement recorded the topsoil sample (Ax horizon, 0-4 in.). The growth in Chapter 11-3 is total nitrogen. The 10 highest difference in the of ryegrass between this growth values of ryegrass were from soils that litter and the mineral topsoil was 90-fold, while ranged in total nitrogen from 0-70% to 0-23% for white clover the difference in growth was and averaged 0 -47%, while the 10 poorest growth 26-fold, but these high rates of growth declined values of ryegrass were from soils that ranged in with time. Litters of Ox horizons therefore greatly totalnitrogenfrom0-69%to0-18%andaveraged increased the amount of plant growth obtained 0-41%. The total nitrogen content of a soil is of in the pot trial, but litters of O, horizons had little value by itself as an indication of nitrogen little to contribute to the nutrition of the plants. availability, since the capability of the soil to The diversity of site vegetation (listed in Table produce available nitrogen is largely dependent 4-3-1) made a comparison of plant growth with upon the microbial population and nature of the the established vegetation obscure, although soils humus material. The value of humus in soils for that gave poor growth of both ryegrass and white supplying nutrients for plants can be expressed in clover in the pot trial were generally sampled terms of the C/N ratio; high values of this ratio from under forest or scrub.

101 TABLE 4-3-1- Growth of Ryegrass and White Clover under Glasshouse Conditions after Ten Weeks

Plant Growth (g/pot) Soil Sample Soil Soil Classification Site Vegetation (from Chapter 11-2) A SB No. Ryegrass

2-04 7672A Rotomahana 2-65 0-61 Recent soil from volcanic ash Scrub bracken, mahoe, coprosma, kamahi, lupin.

- 758 IA Temuka 2 21 1 56 0 65 Gley Pasture Yorkshire fog, poa. - ryegrass, white clover, - - - 7717A Cluden 2-12 1-26 0-86 Yellow-grey danthonia, earth Pasture - native broom. 7588A Waiareka 2-05 1-18 0-87 Nigrescent southern brown granular loam Pasture, tall (R)* Chewings fescue, cocksfoot. - 7514A Paremata 1-78 1-52 0-26 Central yellow-brown earth Pasture danthonia, manuka.

- 7652A Puhoi 1-76 1-37 0-39 Northern yellow-brown Pasture (R) fescue, lotus earth -cocksfoot, paspalum, major. 7538A Barrhill 1-66 1-34 0-32 Southern from loess Pasture Kentucky bluegrass, recent soil under trees -cocksfoot, under oak. 7605A Ahuriri 1-62 1-03 0-59 Central gley Pasture saline recent soil -ryegrass, clover. 7590A Waikakahi 1-60 1-25 0-35 Rendzic intergrade YGE Pasture yarrow, to southern -cocksfoot, thistle. 7589A Steward 1-53 1-28 0-25 Shallow soil associated with southern YGE Pasture Chewings fescue, tussock, sweet vernal.

- 7515A Porirua 1-37 1-26 0-11 Intergrade between YBE YGE Pasture danthonia. central to -ratstail, white clover, 7643A Arapohue 1-36 0-96 0-40 Northern rendzina Pasture -ratstail, paspalum, cocksfoot, clover. 7583A Conroy I 0-74 0-59 Brown-grey hairgrass, -33 earth Pasture scabweed, clover, winged thistle. - 7560A Timaru I*32 1-22 0-10 Yellow-grey earth Pasture tall (R) -twitch. 7584A Lowburn 1-22 0-60 Brown-grey 0-62 earth Pasture scabweed, Poa maniototo, sorrel, hard tussock. - 0-36 7684A Hamilton 1-22 0-86 Central brown granular loam Scrub (R) bracken, thistle, blackberry.

- 7668A Mangaweka 1-16 0-90 0-26 Central yellow-brown earth Pasture cocksfoot, browntop.

- 7536A Judgeford I 16 I 0 14 Central yellow-brown earth Pasture browntop, cocksfoot, bracken. - -02 - - 7561A Selwyn I-15 1-02 0-13 Southern from Pasture browntop, recent soil alluvium - subterranean clover. 7586A Lismore 1-12 1-01 0-11 Shallow soil associated with southern YGE Pasture sweet vernal, catsear.

- 7537A Marton I-05 1-00 0-05 Central yellow-grey Pasture Yorkshire fog, flatweeds. earth - sweet vernal, ryegrass, 7587B Tekapo 1-04 0-94 0-10 High country yellow-brown Tussock hard earth - tussock. 7582A Taitapu 1-01 0-46 0-55 Southern gley Pasture Poa recent soil -ryegrass, red clover, suckling clover, annua. 7715A Manorburn 0-96 0-66 0-30 Solonetzic barley soil associated with BGE Pasture grass, Atriplex spp., sorrel. - o 7585A Templeton 0-91 0-81 0-10 Intergrade between recent soil and YGE Pasture (R) browntop, sweet vernal, flatweeds. - 7654A Waikare 0-77 0-71 0-06 Podzolised (R) northern yellow-brown earth Scrub -manuka (tall), rushes, umbrella fern. 7669A Taupo 0-19 Yellow-brown 0-62 0-43 pumice soil Tussock -manuka, tussock, cocksfoot, bracken, patotara. 7650A Puketeraki 0-02 0-60 0-58 High country yellow-brown earth Tussock snow tussock, hard tussock, blue tussock, celmisia. - Naike 0-06 Central 7683A 0-59 0-53 brown granular loam Pasture ryegrass, white clover, cocksfoot, flatweeds. - 7653A Whangaripo 0-59 0-32 0-27 Northern yellow-brown earth Scrub (R) bracken (tall).

- 7604A Matapiro 0-55 0-46 0-09 Central yellow-grey earth Pasture crested dogstail, ryegrass.

- 7697A Waikiwi 0-54 0-47 0-07 Southern yellow-brown earth Pasture (R) cocksfoot, browntop.

- 7641A Te Kie 0-53 0-46 0-07 Steepland brown granular clay Pasture browntop, sweet vernal, Yorkshire fog, lotus major.

- 7597A Egmont 0-44 0-30 0-14 Central yellow-brown loam Pasture cocksfoot, sweet vernal, ryegrass. - 7698A Otanomomo 0-39 0-20 0-19 Southern organic soil Bog sphagnum, wire rush.

- 7596A Stratford 0-38 0-27 0-11 Central yellow-brown loam Pasture browntop, Yorkshire fog, - cocksfoot, clover. 7657A Papakauri 0-34 0-31 0-03 Red loam Pasture paspalum, browntop, cocksfoot.

- 7534A Belmont 0-30 0-29 0-01 Intergrade YBE loam Pasture browntop, central to yellow-brown - sweet vernal. 7656A Ruatangata 0-25 0-20 0-05 Brown loam Pasture (R) paspalum, browntop, flatweeds, fern, blackberry.

- 7640A Waimatenui 0-25 0-20 0-05 Northern brown granular clay Scrub (R) bracken, manuka.

- 7592A Patua 0-25 0-13 0-12 Central yellow-brown loam Pasture cocksfoot, ryegrass, clover, Yorkshire fog.

- 7638A Kiripaka 0-23 0-15 0-08 Brown loam Pasture (R) fescue, -cocksfoot, clover. 7682A Waiteti 0-23 0-22 0-01 Central yellow-brown loam Pasture (R) browntop, bracken, - moss, sweet vernal. 768IA Tirau 0-21 0-16 0-05 Yellow-brown loam Pasture (R) bracken, - cocksfoot, sweet vernal. 7591A Dannevirke 0-18 0-13 0-05 Intergrade YBL YBE Pasture (R) bracken, blackberry. central to - cocksfoot, thistle, 7642A Tutamoe 0-15 0-15 0-002 Gleyed brown granular clay Pasture (R) browntop, cocksfoot, flatweeds.

- 7535B Taita 0-08 0-06 0-02 Central yellow-brown earth Scrub manuka, Spanish heath, gorse, radiata pine.

- podzol 7655A One Tree Point 0-05 0-04 0-005 Northern ground-water Scrub manuka (short), rushes, umbrella fern, lycopodium. - 7639B Okaihau 0-04 0-03 0-01 Brown loam Scrub manuka, hakea, gorse, fern.

- 7671C Ngauruhoe 0-04 0-01 Recent from 0-03 soil volcanic ash Tussock -red tussock, dracophyllum, celmisia. 7644C Wharekohe 0-01 Northern podzol kauri, 0-04 0-03 Forest - bracken. 7670B Kaingaroa 0-03 0-02 0-008 Yellow-brown pumice soil Scrub dracophyllum, cassinia, moss (near Douglas fir).

- 7719B Okarito 0-03 0-02 0-005 Southern podzol Bog fern, lycopodium, - rushes, moss. 7696F Tautuku 0-02 0-02 0-000 Podzolised yellow-brown Forest kamahi, southern earth - rimu.

*(R) Road reserve.

- 4-3

TABLE 4*3-2* Average Growth Values of Ryegrass and White Clover under Glasshouse Conditions for Soil Groups

Plant Growth (g/pot) No. of Sites Soil Group (Common Name) Ryegrass White Clover

ZONAL 2 Brown-grey earth 0-68 0-59 4 Yellow-grey earth 0 99 0 29 - - 2 Yellow-grey earth to yellow-brown earth I 39 0 19 - - 2 Soils associated with yellow-grey earths 1*15 0-18 2 High country yellow-brown earths, weakly weathered 0-77 0-06 3 Central and southern yellow-brown earths, moderately weathered 0 80 0 16 - - 5 Northern yellow-brown earths, strongly weathered 0-50 0-15 2 Podzols 0-02 0-003

INTRAZONAL 2 Yellow-brown pumice soils 0 23 0 10 - - 5 0 22 0 Yellow-brown loams - -08 4 Brown granular loams and clays 0-44 0-12 4 Red and brown loams 0 17 0 - -05 3 Rendzinas 013 0-54 1 Solonetz associated with brown-grey earths 0 66 0 30 - - 2 Gley soils (and saline gley) 1 30 0 61 - - 1 Organic soils 0-20 0*20

AZONAL 3 Recent soils from alluvium 0 76 0 10 - - 1 Recent soil from loess 1-34 0-33 1 Recent soil from andesitic ash 0-03 0-02 1 Recent soil from lake-bottom mud 2-04 0-61 1 Steepland soil on andesite 0-46 0-08 Average values 0-63 0*27

TABLE 4*3-3* Average Growth Values of Ryegrass and White Clover under Glasshouse Conditions for Soils at Different Degrees of Leaching

Ryegrass (g/pot) White Clover (g/pot) No. of Degree of Sites Soil Leaching Range Average Range Average

8 Very weak 2-04-0-46 1-01 0-87-0-05 0-41 10 Weak 1-56-0*31 0-99 0-86-0-04 0*39 16 Moderate 1-52-0-15 0-78 0-36-0*05 0-14 13 Strong 0-58-0-02 0-26 0-27-0-005 0-06 7 Very strong 0-15-0-02 0-06 0-12-0-000 0-02

GROWTH VALUES IN RELATION TO and white clover. Little growth of either plant SOIL CLASSIFICATION occurred on soils derived from volcanic materials: and brown loams from basalt, yellow-brown The amounts of ryegrass and white clover red loams from and mixed ash, and yellow- grown under glasshouse conditions have been andesitic brown pumice soils from rhyolitic ash. The organic grouped in terms of the New Zealand soil classi- produced little growth. fication in Table 4-3-2. Three soil intergrades soil also have been omitted from the table. The statistical Results from the azonal soils were very varied. gave significance of this table is limited by the number The recent soil from muddy volcanic ash high yields of sites in the group in many cases only one site very of ryegrass and white clover, is investigated. while recent soil from accumulating andesitic gave little growth plant. Among the zonal soils ryegrass attained maxi- ash very of either mum growth on the yellow-grey earths while The degree of soil leaching is related to a number white clover, with a higher requirement for phos- of other soil properties and can be assessed ap- phorus, attained its maximum growth on the proximately by the percentage base saturation brown-grey earths. of the topsoil. In Table 4*3-3 the amounts of gley In among the intrazonal soils, the soils growth of ryegrass and white clover, after 10 and rendzinas produced large amounts of ryegrass weeks in a glasshouse, have been arranged accord-

103 4*4 ing to five stages of soil leaching, irrespective of growth values showed a continuous decrease with higher categories in the soil classification. This increasing degree of soil leaching. table shows that the first major reduction in rye- grass growth occurred between moderate and the ACKNOWLEDGMENTS strong stages of soil leaching, while for white clover the first major reduction in growth occurred The assistance given by Mr. C. C. Jackson, between the weak and moderate stages of soil Botany Division, Department of Scientific and leaching. The range of growth values at any one Industrial Research at Taita in preparing the pots stage of soil leaching was greater for white clover of soil and tending the plants is acknowledged. than for ryegrass and for both plants the average The photographs were taken by Mr R. Julian.

4-4- CHANGES INDUCED IN THE SOR BY PASTORAL FARMING

by T. W. WALKER Lincoln College, University of Canterbury

INTRODUCTION being carried on the extra herbage grown on improved pastures, owing in large measure to The distribution of the great natural grasslands the use of fertilisers, lime, better strains of herbage of world is determined primarily by climate the species, better pasture management, and control and in particular by aridity for at least some of months of the year (Thornthwaite, 1952). At etsbest natural grassland soils of the world the time of European settlement, low-tussock have always been prized by man because of their grasslands grew on semi-arid brown-grey the excellent physical and chemical properties asso- earths and the drier yellow-grey earths, and tall ciated with high levels of mull organic matter, a tussock on some of yellow-brown earths in the good calcium status, a well distributed root system, South Island. Tall also flourished the tussock good structure and drainage, and high biological above bush line in both islands,. but at lower the activity including large numbers of earthworms. altitudes in the North Island was hmited. . small to The establishment and maintenance of high- areas mainly on the yellow-brown pumice soils producing grass-clover associations sets in train and recent soils from volcanic ash around Mt. a series of processes that result in soils possessing Ruapehu. The vegetation had already been modi- many properties in common with the best natural fied in some areas by earlier Polynesian fires, and grassland soils. a coincidental change in climate may have retarded forest regeneration (for the most recent discussion of problem in South Island see Molloy this the so - et al., 1963). Some of these native grasslands particularly 70 - at the lower altitudes, have been cultivated, ferti- lised, and sown with improved strains of grasses see, solvalents and clovers; others have been improved by over- ’o - sowing with seeds and fertilisers, but vast areas have deteriorated rather improved under than the so - impact of pastoral farming and rabbits. The present grasslands of North Island have been the con- rocalacemoccupied 40- verted mainly from former forest soils. Of the -- by agriculture ,--*** 44 million acres occupied for farming, some 20 ,--** million are now classed as improved while some 30 - 13 million are still in tussock and about 6 million in fern are and scrub. Some 90% of stock is 20 / the ------&- carried on the improved land, and as shown in improved and cultivated land Fig. 4-4-1 stock numbers, which increased at a ,,-***^ so- --’ rate similar to the area of land being farmed / ,--- until about 1920, have since increased sharply, ’,-* although area has kept almost constant. The ?840 the 1890 1909 id11 Id51 Id60 is most obvious explanation that more stock are FIG. 4-4-1- Land use and stock numbers in New Zealand.

104 HIGH COUNTRY YELLOW-BROWN EARTHS SOUTHERN YELLOW-BROWN EARTH Moderately leached Strongly leached Strongly leached

Tekapo Paketeraki Waikiwi

INTERGRADE CENTRAL YELLOW-8ROWN CENTRAL YELLOW-8ROWN EARTH EARTH TO YELLOW-BROWN LOAM CENTRAL YELLOW-BROWN EARTH Moderately leached Weakly leached Moderately feached to strongly Strongly leached

Mangaweka Judgeford Belmont Taita

PODZOLISED NORTHERN YELLOW-BROWN EARTHS NORTHERN YELLOW-8ROWN EARTH NORTHERN PODZOL Weakly leached Moderately strongly leached Strongly leached Very leached to . strongly

Pubol Whangaripo Walkare Wharekohe

PODZOLISED SOUTHERN YELLOW-BROWN EARTH SOUTHERN GLEY PODZOL NORTHERN GROUNDWATER PODZOL Strongly leached Very strongly leached Very strongly leached

Tautuku Okarito One Tree Point

PLATE 22. Growth of ryegrass on untopdressed soils. BROWN-GREY EARTHS

Weakly eached Weakly leached

Lonroy Lowburn

SOUTHERN YELLOW-GREY EARTHS CENTRAL YELLOW-GREY EARTHS

Weakly leached Moderately ieached Weakly leached Moderately leached

Cluden Timaru Marton Matapiro

INTERGRADE CENTRAL YELLOW-BROWN CENTRAL EARTH TO YELLOW-GREY EARTH YELLOW-BROWN EARTH Moderately teached Moderate y leached

Porirua Paremata

SHALLOW SOILS ASSOCIATED WITH SOUTHERN YELLOW-GREY EARTHS Moderately leached Moderately reached

Steward Lismore

PLATE 21. Growth of ryegrass on untopdressed soils. RENDZiC INTERGRADE TO NIGRESCENT SOUTHERN SOUTHERN YELLOW-GREY EARTH NORTHERN RENDZlNA BROWN GRANULAR CLAY Very leached Very weakly Very weakly leached weakly leached

Walkakahi Arapohue Waiareka

SOLONETZIC SOIL ASSOCIATED WITH B-GREY EARTHS CENTRAL SALINE GLEY RECENT SOIL SOUTHERN GLEY SOIL SOUTHERN ORGANIC SOIL Very weakly leached Very weakly leached Weakly teached Strongly leached

Manorburn Ahuriri Temuka Otanomomo INTERGRADE SOUTHERN RECENT SOIL SOUTHERN RECENT SOIL BETWEEN SOUTHERN RECENT FROM LOESS FROM ALLUViUM SOIL AND YELLOW-GREY EARTH SOUTHERN GLEY RECENT SOIL Weakly reached Weakly leached Moderately leached Very weakly leached

Barrhill Selwyn Templeton Taitapu

CENTRAL RECENT SOIL FROM VOLCANIC ASH DNNUO HERN Very weakly leached Strongly leached BF Very weakly leached

Rotomahana Ngauruboe Te Kie

PLATE 24. Growth of ryegrass on untopdressed soils. SOIL CENTRAL YELLOW-BROWN LOAMS YELLOW.BROWN PUMICE SOtt YELLOW.BROWN PUMICE Strongly Moderately leached Moderately leached teached Very strongly teached

Taupo Tirau Waited Kaingaroa

[NTERGRADE CENTRAL YELLOW-B EARTH TO YELLOW.BROWN LOAM CENTRAL YELLOW-BROWN LOAMS Strongly Moderately leached Moderately leached Strongly leached teached

Egmont Stratford Patua Dannevirke

BROWN GRANULAR LOAMS CENTRAL NORTHERN BROWN GRANULAR CLAY GLEYED 8ROWN GRANULAR CLAY Moderately leached Moderately ierched Strongly leached Strongly leached

Nalke Hamilton Waimatenui Tutamoe

RED LOAM BROWN LOAMS Weakly leached Moderately leached Strongly teached Very strongly leached

Papakauri Kiripaka Ruatangata Okathau

PLATE 23. Growth of ryegrass on untopdressed soils. HIGH COUNTRY YELLOW-BROWNSEARTH SOUTHERN YELLOW-BROWN EARTH y Moderately leached trong eached Strongly leached

Waikiwl Tekapo Puketeraki

INTERGRADE CENTRAL YELLOW-B EARTH TO YELLOW-BROWN LOAM CENTRAL YELLOW-BROWN EARTH CENTRAL YELLOW-BROWN EARTHS Moderately strongly leached Strongly leached Weakly leached Moderately leached to

Belmont Taita Mangaweka judgeford

PODZOLISED NORTHERN YELLOW- NORTHERN YELLOW-BROWN EARTHS BROWN EARTH NORTHERN PODZOL Moderately leached leached Very strongly leached Weakly leached to strongly Strongly

Waikare Wharekohe Pubol Whangaripo

PODZOLISED SOUTHERN YELLOW- BROWN EARTH SOUTHERN GLEY PODZOL NORTHERN GROUNDWATER PODZOL Very strongly leached Strongly leached Very strongly leached

Tautuku Okarito One Tree Point

PLATE 26. Growth of white clover on untopdressed soils. BROWN-GREY EARTHS Weakly leached Weakly teached

Cpnroy Lowburn

SOUTHERN YELLOW-GREY EARTHS CENTRAL YELLOW-GREY EARTHS leached Moderately Weakly leached Moderately Moderately leached teached

Cluden Timaru Marton Matapiro INTERGRADE CENTRAL YELLOW-BROWN EARTH TO YELLOW-GREY EARTH CENTRAL YELLOW-BROWN EARTH Moderately leached Moderately leached

Porirua Paremata

SHALLOW SOILS ASSOCIATED WITH SOUTHERN YELLOW-GREY EARTHS Moderately leached Moderately leached

Steward Lismore

PLATE 25. Growth of white clover on untopdressed soils, INTERGRADE TO RENDZiC NIGRESCENT SOUTHERN SOUTHERN NORTHERN RENDZINA YELLOW-GREY EARTH BROWN GRANULAR CLAY Very leached Very weakly leached weakly Very weakly leached

Waikakabi Arapohue Walareka

SOLONETZIC SOIL ASSOCIATED CENTRAL SALINE GLEY WITHVBROWa G Y EARTHS SeTched Ver SOU N GaLEh SOUTH RN R ANIC SOIL weEaNT dSOIL

Manorburn Ahuriri Temuka Otanomomo INTERGRADE SOUTHERN RECENT SOIL SOUTHERN RECENT SOIL 8ETWEEN SOUTHERN RECENT SOIL AN ELLOeW-GaR WReOk1yLOa d LL UM SOUTHVERN GeLE ECdNT SOIL aMki dEARTH

Barrhill Selwyn Templeton Taitapu

CENTRAL RECENT SOIL FROM VOLCANIC ASH STEEPLAND NORTHERN Very weakly leached BROWN GRANULAR CLAY Strongly leached Very weakly teached

Rotomahana Ngauruhoe Te Kie

PLATE 28. Growth of white clover on untopdressed soils. YELLOW-BROwN PUMICE SOIL CENTRAL YELLOW-BROWN LOAMS YELLOW-BROWN PUMICE SOIL Moderately teached Moderately leached Strongly leached Very strongly leached

Taupo Thrau Waiteti Kaingaroa

INTERGRADE CENTRAL YELLOW BROWN LOAM TO YELLOW-BROWN CENTRAL YELLOW-8ROWN LOAMS EARTH Moderately leached Very Moderately teached strongly leached Strongly leached

Egmont Stratford Patus Dannevirke

NORTHERN BROWN GRANULAR CENTRAL BROWN GRANULAR LOAMS CLAY GLEYED BROWN GRANULAR CLAY Strongly leached Moderately leached Moderately leached Strongly leached

Naike Hamilton Waimatenui Tutamoe

RED LOAM BROWN LOAMS Weakly leached Moderately leached Strongly teached Very strongly teached

Papakauri Kiripaka Ruatangata Okathau

PLATE 27. Growth of white clover on untopdressed soils. 4*4

THE ECOLOGY OF choice. The dependence in New Zealand pastures GRASS-CLOVER ASSOCIATIONS upon biological fixation of nitrogen by clovers, whose rather exacting nutritional requirements are It is worth examining the natural ecological subject to the strong competition offered by the niche for legumes such as the clovers, in order to associated grasses, particularly as the nitrogen appreciate better some of the changes that must content of the soil improves, necessitates among be made to establish grass-legume associations. Other things, the correction of deficiencies such Studies of chronosequences of soils and vegetation as P, S, Ca, K, Mg, Mo, B, and Cu, and of heavy indicate the vital pioneer role played by plants metal toxicities occasioned mainly by acidity, and, that have some symbiotic mechanism for fixing in some cases, the inoculation of clovers with nitrogen. Under favourable conditions nitrogen suitable rhizobia. accumulation in soils is rapid, and depends this Soil physical conditions, particularly those caus- on an adequate supply of all essential plant ing poor drainage, may also need correction to nutrients except nitrogen. With addition of the establish grass-clover associations. prepared combmed nitrogen to the soil, the way is for a whole succession of plants not known to NUTRIENT REQUIREMENTS OF fix nitrogen, and the nitrogen fixers may soon be growth GRASS-CLOVER ASSOCIATIONS suppressed by the very plants whose they made possible. This suppression may arise from The need to ensure that clovers have adequate competition for light, nutrients, or moisture, or supplies of nutrients means that the amendments the sensitivity of nitrogen-fixers to the complex the . required to establish a grass-clover association factors of acidity if the soil pH drops. Walker will depend on the stage of a soil’s development as (1963) suggested that the first two nutrient de- governed by the soil-forming factors. The broad ficiencies likely to arise are phosphorus and/or pattern of such amendments can be demonstrated sulphur, former when all the available inor- the . by brief reference to the main zonal soils whose ganic phosphorus has become incorporated into. properties have been described fully in earlier the organic cycle, and the latter when virtually chapters. all the sulphur in the soil is in the organic form In brown-grey earths the main nutrient where of are low. the and atmospheric returns sulphur growth is deficiency restricting. clover that of Certainly in grass-clover associations under condi- sulphur. Because accumulation of organic matter tions where the only source of inorganic phos- has been restricted by low rainfall, levels of organic phorus and sulphur is from mineralisation of the phosphorus, nitrogen, are also rela- grasses and sulphur organic matter, compete effectively. for low, and there are large reserves of inorganic nutrients along with any minerahsed- nitrogen, tively these phosphorus, mainly apatite as shown in Table and clovers are suppressed. Without further addi- 4-4-1. As long as weathering can maintain ade- tions of inorganic phosphorus and sulphur the quate supplies of phosphorus and essential elements nitrogen content of the ecosystem cannot be sulphur, sulphur will continue be permanently Other than to the increased. This hypothesis certainly. main deficiency. paucity legumes in explains the of the world’s yellow-grey With increasing rainfall the earths natural grasslands and accounts for the presence contain more organic matter, and a very high of active nitrogen fixers in very youthful or re- proportion of the total phosphorus becomes juvenating soils. incorporated in it, accounting for the phosphorus In areas where precipitation is high enough to responses on pastures. Sulphur deficiency is also cause more leaching is common in most than widespread and, with declining pH, responses are natural grassland areas, progressive soil develop- also obtained to lime and/or molybdenum. With ment leads increasing C/N, C/S, and C/organic to the possible exception of sulphur deficiency, the P ratios and falling pH values, unless weathering occurrence of which depends so much on atmos- of minerals maintains supply of temporarily the pheric returns, these deficiencies are also wide- calcium, magnesium, and potassium. The slowly spread in the yellow-brown earths. With increased diminishing give supply of nutrients may rise to leaching and weathering, exchangeable cations a succession of vegetation better able to tolerate reach a peak in the yellow-grey earths and there- slowly deteriorating conditions, and mor the after drop sharply, with magnesium holding on organic matter may eventually accumulate. relatively better than calcium and potassium It follows that growing a grass-clover association (Table 4-4-1). Levels of trace elements such as on any soil other than a very recent one is an cobalt and copper have also been shown to decline attempt to put back the ecological clock to an in weathering and leaching sequences of soils earlier phase, using a biotic association of man’s (Taylor et al., 1956).

105 4-4

TABLE 4-4-1- Weight of Various Elements (lb per acre-profile) in a Sequence ofZonal Soils Arranged in Order of Increasing Weathering and Leaching (Data on C, N, S, and P from Walker and Adams (1959)

Soil Tekapo Dry Tekapo Hill Haldon Marua Rangiora Hukerenui

Depth of Profile (in.) 19 19 26 34 37 33

C 36,000 57,000 109,000 208,000 155,000 123,000 N 4,100 6,700 9,700 12,100 7,600 5,000 S 390 600 1,060 2,500 1,800 770 Organic P 820 1,040 3,240 2,720 510 660 Total P* 2,790 3,110 4,160 3,840 1,450 1,020 Exch. Ca 6,180 6,140 12,860 1,170 330 90 Exch. Mg 2,350 900 1,420 590 630 360 Exch. K 280 760 1,520 330 270 180 Exch. Na 200 140 330 90 190 200

*Much of the inorganic P (total minus organic P) in the Tekapo soils is Ca-bound, whereas in the last three members of the sequence it is Fe- or Al-bound.

TABLE 4-4-2- Content of Various Elements in Pastures (from the Taupo sandy silt set) of Increasing Age, Getting Regular Superphosphate Dressings

Age of Organic P Depth a % C % N % S (in.) Organic P Total P Total P

0 0-4 10*1 0*31 0*036 0*043 0-047 90 4-8 3-9 0-17 0-031 0-032 0-038 85 li 0-4 4*2 0*20 0-038 0-052 0-070 75 4-8 4-1 0-20 0-039 0*047 0-056 85 3 0-4 4-7 0-22 0-040 0-035 0*072 50 4-8 5-7 0-24 0-039 0-037 0-043 85 5 0-4 4-8 0-30 0-049 0-052 0-071 75 4-8 4-7 0-28 0-046 0-054 0-064 85 8 0-4 5-6 0-43 0-062 0-049 0-077 65 4-8 3-5 0-23 0-046 0-034 0-042 80 15 0-4 6-2 0-45 0-062 0-058 0-103 55 4-8 2-8 0-23 0-037 0-046 0-058 80 25 0-4 6-3 0-59 0-071 0-058 0-103 55 4-8 3-8 0-21 0-039 0-026 0-037 70

INDUCED SOIL CHANGES to grasses and clovers sown on the cultivated soil. As shown in Table 4-4-2 organic phosphorus Organic matter. The correction of all the factors made up almost 900/o of P in 8 in. necessary to establish a grass-clover association the total the top in virgin soil, accounting for very acute results in an automatic increase in the nitrogen the the phosphorus deficiency initially inhibiting clover content of the man-made ecosystem. This is growth. Sulphur have been deficient, reflected either in an increase in the level of mull may also and on oldest pasture some 500 lb per acre organic matter or in the gradual conversion of the phosphorus had been mor into mull organic matter. and sulphur applied over 25 years. The gradual narrowing of C/N, Watkin (1949), working on the soils from trials the the C/S, C/organic P particularly in described in a classical series of papers by Sears and ratios, the 4 in., is over 25 years et al. (1953), found increases in mull organic top shown clearly, and the depth 8 in, increased matter in a recent alluvial soil, which contained the weight of nitrogen to a of from 1,820 4,460 lb per acre, a mean annual 0-25% N where grass alone was grazed and 0-33% to increase 104 lb. Carbon increased from 53,200 N where grasses and clover were grazed, after only of only 56,000 lb per acre, and main change 3 years. An outstanding example, from the work to the was a gradual lowering of C/N of Baumgart and Browning, of the conversion of therefore the due primarily accumulation of nitrogen. mor to mull organic matter was quoted by Dixon ratio to Jackman (1960 pers. comm.) has obtained and Jackman (1954). A similar situation was and data for large of sampled by Walker, Thapa, and Adams (1959) on similar a number soils. soils belonging to the Taupo sandy silt set, where The percentage levels to which mull organic pastures had been developed after scrub for various matter will eventually rise is still not certain, but periods of time by application of superphosphate equilibrium levels must be reached when the rates

106 4-4

be but of addition to and losses from the ecosystem are only enables more stock to carried, the equal. Theoretical calculations (Walker, 1956) absence of a matted turf makes it more susceptible particularly in suggest very high values at equilibrium, and many to hoof damage the wetter climates be New Zealand grassland soils are extraordinarily where the soils would normally afforested. rich in organic matter. Jackman’s data (1960) Treading affects pasture production, herbage suggest that so far the increase is taking place composition, and soil structure. Edmond (1958a mainly in the surface few inches. We need to know and b) has shown that production may be lowered more about the factors affecting decomposition by 10 to 40% depending on stocking rate, season, of organic matter such as the nature of clay- soil, and herbage constituents. Heavy treading of organic matter complexes, and also where losses soils saturated to field capacity caused very large of such elements as nitrogen are occurring. reductions in yield. Not all effects are deleterious, as Yorkshire fog and meadow grass are more Structure. There is little experimental work . 2n easily damaged than better grasses. Treading on New Zealand measuring effects of changes in puddling, the the soil itself leads to compaction, reduc- organic matter on such properties as soil structure, gleying tion in permeability, and even signs of rates, and drainage. Watkin (1949) infiltration in the surface inch or so, particularly in winter quoted by Sears and Evans (1953) noted return that when the soils are wet. Gradwell (1956) found of dung and urine on grass-clover associations not only a reduction in pore space but an increase compared with on cloverless swards caused that in small pores, and in one wet soil in winter increases in proportion of large soil marked the (Gradwell, 1960) air space was only 3% pf the aggregates (> 1-2 mm diameter) at the 6-9 in, total soil volume. On the other hand, treading depth. Striking visual differences on first ploughing may compact light pumice soils, and Packard in were also obvious (Sears, 1953), soil the plant the (1957) suggested that this may improve grass-alone plots being paler in colour, stickler, growth on soils. Increasing attention is glaze these and showing a distmet on the furrow slice. from grazing being given to restricting damage pastures soils are wet by provision of Earthworms. The increase in quantity or quality when the loafing barns and the like. of organic matter might be expected to effect changes in numbers and kinds of soil microbes Macronutrients. Wherever the nitrogen content and macrobes (an admirable word coined by of soils increases owing to the stimulation of Jacks (1963) for soil organisms visible to the naked clovers by the correction of deficiencies, organic eye). Sears and Evans (1953) showed that numbers sulphur and phosphorus will also tend to increase and weights of earthworms closely followed yields as shown in Table 4-4-2, as also will cation- of herbage. After about 5 years of growing grass exchange capacities where amounts of organic alone without return of dung and urine, the worm matter increase. Levels of adsorbed sulphate may population (mainly Allolobophora caliginosa and also increase in some acid subsoils, as will inor- had from I Lumbricus rubellus) risen about million in ganic phosphorus in the surface soil either 1 million per acre weighing 4 owt, while under to Ca-bound or more usually in Al- or Fe-bound comparable conditions on a high-yielding grass- forms (Saunders 1959). clover association, the population rose to more Walker et al. (1954) have argued that loss of 2 million per acre weighing 14 cwt. than from grassland nitrate. by leaching soils is small Stockdill (1959) has demonstrated very the by owing rapid uptake of mineral nitrogen important part played by earthworms in prevent- to grasses or by micro-organisms decomposing dead ing sod-bound conditions and improving soil roots. However Dr G. Butler (pers. comm.) structure and herbage production, and the value found large amounts of nitrate-N in drainage of introducing Allolobophora caliginosa to areas Grasslands Research Station, and yet penetrated water at the not by this species, losses may be heavy probably from urine patches plant growth is Treading by Farm Animals. The increased bio- during the winter when restricted light. Any logical activity leading to more rapid decomposi- by low temperatures and nitrate, sul- phate, is lost by leaching must be tion of dead roots, litter and dung may not be or chloride that by will beneficial in every respect. The superficial layer of accompanied cations, and while calcium be dominant lost, matted roots that tends to form particularly on normally the cation magnesium potassium be lost, by Dixon low-fertility, acid, clover-deficient swards may give and will also as shown (1958), lower production, but it withstands the traffic and Taylor (1942), Saunders and Metson (1960 1962). of farm animals owing to the springy nature of and Hogg and levels be or the turf, which resists penetration by hooves. A Although calcium may maintained highly productive grass-clover association not even improved from applications of lime and

107 4-4

superphosphate, levels of potassium and mag- soils include copper, molybdenum, and boron. nesium may eventually need correction. This is Deficiencies of these elements have not necessarily already so for potassium in many of the more been induced by pastoral farming, and it is in strongly weathered and leached zonal soils and fact the correction of such deficiencies and others in soils whose parent materials contain relatively that leads to improvement in soil fertility. Molyb- small amounts of potassium. The biggest drain on denum deficiency arises primarily because of the potassium (and any other element) occurs where relatively high demand of legumes for molybdenum, herbage is cut and removed and fed out elsewhere, particularly where it is necessary to keep dressings but because most of the potassium ingested by an of lime to a minimum. Indeed, where liming is practised animal is excreted in the urine it is collected from in pastoral farming, molybdenum de- a large area by the grazing animal and concen- ficiency is likely to be corrected rather than in- trated in relatively small urine patches. Even if duced. On the other hand, liming may intensify no potassium were lost from urine patches by copper deficiency in herbage on certain acid peats, leaching, it is obvious that areas not receiving and possibly boron and cobalt deficiencies on urine will become depleted of potassium. Potassium other soils. No cases of cobalt deficiency affecting deficiency is increasingly recognised as limiting clover growth have been reported, even in areas pasture production on many soils, and this indi- where stock may suffer from severe cobalt de- cates without doubt that the deficiency even if not ficiency. This deficiency in animals now occurs in present initially is being induced by pastoral areas formerly believed to be free of cobalt de- farming. On the other hand on a recent soil from ficiency and may result from increased herbage alluvium (Wakanui silt loam) at Lincoln, where production effected by the use of fertilisers and illite is the dominant clay mineral (as it is in the lime, thus intensifying cobalt deficiency in mar- yellow-grey earths generally), Metson and Hurst ginally deficient areas. Copper deficiency in (1953) found that the removal of 1,000 lb per acre animals may be induced on some soils by liming ofK,O in dung and urine did not significantly lower or by the use of molybdenum (Cunningham, the level of exchangeable potassium in the soil. 1955). Manganese toxicity may reduce clover growth levels may be lowered Only one well authenticated case of a pasture on some soils, and by applications of molybdenum, or more surely response to magnesium has been reported in by liming (Walker et al. 1955). Manganese de- New Zealand (Moody, 1962), and this was on a ficiency in herbage plants must be surprisingly soil primarily used as a forest nursery. Other rare, as no authentic cases have been reported, pasture responses to magnesium have been re- possibly because susceptible soils such as peats ported, but in circumstances where associated and podzols are rarely very heavily limed. Un- anion effects (e.g. sulphate, silicate, or carbonate) questionably, as herbage production is increased cannot be discounted entirely. Hypomagnesaemia by deficiencies, is known however, particularly in dairy cows correcting macronutrient and more stock are carried with greater removal of micro- during phases of grass dominance in which the nutrients, deficiencies of elements will non-clovery herbage tends to be relatively low these become more A sharp of in magnesium, and also in suckling beef herds at common. reminder their potential significance is recent discovery of calving. Magnesium is an element that will de- the a widespread deficiency of selenium affecting mand increasing attention in the future. Like animal health, although it is soon say that calcium and phosphorus, most of the magnesium too to it has been induced by pastoral farming (Watkin- is returned in the dung of animals, and in the son, 1962). Wherever herbage production is being absence of readily soluble anions such as chloride improved, it will be profitable pay far more and sulphate, which are returned mainly in the to attention possible effects on contents of both urine, leaching losses of magnesium from dung to patches macro- and micronutrients and to see how far are not likely to be heavy; Davies et al. herbage quality can be improved by soil (1963) reported actual increases in exchangeable treatments. magnesium under dung patches. The much lower Changes indicated by crops. Changes in soil incidence of hypomagnesaemia in dairy cows in fertility may be measured not only by increases New Zealand compared with Holland and Great in herbage production and animal products but Britain is probably due, in part, to the greater also by cropping. Sears (1953) obtained very contribution of clovers to the diet, as clovers tend large yields of crops after ploughing highly pro- contain higher levels of magnesium do to than ductive grass-clover pastures grasses. compared with those after ploughing low-producing cloverless swards. Micronutrients. Trace elements needed to estab- Wheat yields in New Zealand have increased lish vigorous grass-clover associations on some from an average of about 25 bushels per acre in

108 4-4

HOGG, D. E. Magnesium Losses from Horotiu Sandy 1920 to about 50 (Walker, 1962), and some of 1960: ant Ap3p ca8t n of Potassium Chloride. this increase is due to better grassland management FollioTng and improved soil fertility. Large numbers of - 1962: Studies on Soil Magnesium. 1. A Laboratory Investigation into Displacement and Replacement of experiments carried out by the Department of the Magnesium in Soils. N.Z. J. Sci. 5: 64-73. Agriculture show little or no response of autumn- JACKMAN, R. H. 1960: Pasture and Soil Improvement. phosphorus fertilisers, soil sown wheat to nitrogen or Proc. N.z. Soc. sci. 4: 24-7. certainly for the first crop after good grass and JACKS, G. V. 1963: The Biological Nature of Soil Pro- ductivity. Soils and Fert. 26: 147-50. often extending into the second and third crops. METSON, A. J.; HURST, F. B. 1953: Effects of Sheep Dung Although Sears’ experiments (1953) on recent and Urine on a Soil under Pasture at Lmcoln, Canterbury, from alluvium in Manawatu showed soils the that with Particular Reference to Potassium and Nitrogen 327-59. the major benefit from ploughing a good pasture Equilibria. N.Z. J. Sci. Tech. A35: C. Cox, J. E.; JOHNSTON, is obtained in the first crop, this is not necessarily MOLLOY, B. P. BURROWS, J.; .F. P. IS906u3thDisltr buti of Sub sl in all soils, and in Canterbury a marked benefit so eA.ain ,ARED may extend over a few successive crops (Dr K. Bot. 1: 68-77.

O’Connor, pers. comm.). MooDY, R. W. 1962: Magnesium Deficiency in Pastures. Proc. N.Z. Grassl. Ass. 24: 151-60.

PACKARD, R. Q. 1957: Some Physical Properties of Taupo UNIMPROVED AREAS Pumice Soils of New Zealand. Soil Sci. 83: 273-89. SAUNDERs, W. M. H. 1959: Effect of Phosphate Topdressing While roductivit and fertilit of 20 million the on a Soil from Andesitic Volcanic Ash. 2. Effect on Dis- have improved, acres been definitely an almost tribution of Phosphorus and on Related Chemical equal area containing, rather surprisingly, much Properties. N.Z. J. agric. Res. 2: 445-62. H. M.; METSON, A. J. 1959: Fate of Potassium of original area of native grasslands, has SAUNDERS, W. the Soil Derived from Andesitic Applied to Pasture on a deteriorated rather improved. One of than the Ash. N.Z. J. agric. Res. 2: 1211-31. for greater development formerly reasons the of SEARS, P. D.; MELVILLE, J.; EVANS, L. T. 1953: Pasture afforested areas is the higher potential pasture Growth and Soil Fertility. N.Z. J. Sci. Tech. A35, Suppl. 1: 1-77. productivity owing to more reliable rainfall. Some STOCKDILL, S. M. J. 1959: Earthworms Improve Pasture slopes are so steep and the nature of the soils are Growth. N.Z. J. agric. 98: 227-33. such that even where attempts are made to im- TAYLOR, N. H.; CUNNINGHAM, I. J.; DAVIEs, E. B. 1956: prove herbage production, it is the cover and Soil Type in Relation to Mineral Deficiencies. Proc. 7th difficult to avoid erosion which has been intensi- int. Grassl. Congr., pp. 357-67. fied by burning and overgrazing. THORNTHWAITE, C. W. 1952: Grassland Climates. Proc. 6th int. Grassl. Congr. 1: 667-75. There is no question that vast areas particularly T. W. 1956: The Accumulation of Organic Matter of low-altitude country, and land ALKER, the tussock in Grassland Soils. Trans. 6th int. Congr. Soil Sci. B: reverted to fern and scrub in the wetter areas, 409-16. Trends in Soil Fertility. Proc. N.Z. Inst. can be improved by aerial topdressing and over- - 1962: agric. Sl9163 sowing with clovers and grasses or by sod-seeding. P450bl ms of Soil Fertility in a Grass - These depleted acres offer an immense challenge. Animal Regime. Trans. It Meet. Comm. IV and V, int. Soc. Soil Sci. (1962), pp. 704-14.

WALKER, T. W.; ADAMS, A. F. R. 1959: Studies on Soil REFERENCES Organic Matter: 2. Influence of Increased Leaching at Various Stages of Weathering on Levels of Carbon, CUNNINGHAM, I. J. 1955: Molybdate Topdressing and Nitrogen, Sulphur, and Organic and Total Phosphorus. Animal Health. N.Z. J. Agric. 90: 196-202- Soil Sci. 87: 1-10.

DAVIES, E. B.; HOGG, D. E.; HOPEWELL, H. G. [1963]: WALKER, T. W.; ADAMs, A. F. R.; ORCHISTON, H. D. 1955: Extent of Return of Nutrient Elements by Dairy Cattle: The Effects and Interactions of Molybdenum, Lime and Possible Leaching Losses. Trans. Jt Meet. Comm. IV and Phosphate Treatments on the Yield and Composition of V, int. Soc. Soil Sci. (1962), pp. 715-20. White Clover, Grown on Acid, Molybdenum Responsive DixoN, J. K.; JACKMAN, R. H. 1954: Some Chemical Aspects Soils. Plant and Soil 6: 201-20. of Pumice Soils (A Summary). Proc. N.Z. Soc. Soil Sci. 1: WALKER, T. W.; ORCHISTON, H. D.; ADAMs, A. F. R. 19-21. 1954: The Nitrogen Economy of Grass Legume Associa- DIxoN, J. K.; TAYLOR, N. H. 1942: Losses of Exchangeable tions. J. Brit. GrassL Soc. 9: 249-74. Potash and Magnesia Contents from Waikato Soils WALKER, T. W.; THAPA, 8. K.; ADAMs, A. F. R. 1959: Following Continued Phosphate Topdressing. N.Z.J. Studies on Soil Organic Matter. 3. Accumulation of Sci. Tech. A24: 146-51. Carbon, Nitrogen, Sulphur, Organic and Total Phos- phorus in Improved Grassland Soils. Soil Sci. 87: 135-40. EDMOND, D. B. 1958a: The Influence of Treading on Pasture. A Preliminary Study. N.Z. J. agric. Res. 1: 319-28. WATKIN, B. R. 1949: A Study of the Influence of Animal 1958b: Some Effects of Soil Physical Condition on Manure and Clover on the Structural and Chemical - Ryegrass Growth. lbid. 1: 652-9. Characteristics and the Earthworm Activity in a Mana- Soil. Thesis Presented for Degree of M. Agr. Sci., GRADWELL, M. W. 1956: Effects of Animal Treading on a watu Massey College. Wet Alluvial Soil under Pasture. Proc. N.Z. Soc. Soil Sci.2: 37-9. WATKINSON, J. H. [l963]: Soil Selenium and Animal Health. 1960: Changes in the Pore-space of a Pasture Top- Trans. It Meet. Comm. IV and V, int. Soc. Soil Sci. ----- soil under Animal Treading. N.Z. J. agric. Res. 3: 663-74. (1962), pp. 149-54.

109 4-5

4*5* SOME SOIL-PLANT-ANIMAL RELATIONSHIPS

by W. B. HEALY

Each soil has its own pattern of nutrient avail- differences in element composition occurring at plant ability, which is a reflection of parent material the soil and level may be even further nar- and processes of formation (Chapters 2 and 7), rowed. Since different tissues within the animal and it is through these differences in availability can selectively accumulate certain elements, the that soils make their impact on the composition composition of some tissues may reflect soil-plant of pasture. Addition of fertilisers is designed to influences, while others will not. Probably the raise the availability status of certain elements final buffering effect on original soil differences to an optimum level for plant growth, but addition is demonstrated in an animal secretion such as of fertilisers is not alone sufficient to erase funda- milk, which, under the control of the mammary mental soil differences. In fact, each soil adjusts gland, appears to be a product showing relatively in its own way to the new conditions presented by little variation in element composition. Analysis topdressing. The plant also produces its own for macro- and microelements in milk from cows impact on the soil environment, particularly in grazing pasture on different soils in North Auck- the root zone. Here in the ’market place’ of the land, Hauraki Plains, Taupo District, and Tara- rhizosphere the properties of the soil and the naki illustrates this point (Tables 4-5-1 and plant interact, and the macro- and microelement 4-5-2). composition of the plant reflects this. The demands That microelement diKerences present in soil of the plant can alter what might be called the persist through the plant to the animal level at ’inherent’ availability of a soil and in some cases all is remarkable, considering the selection and be sufficiently great to lessen diferences in element narrowing that can take place at each stage. New availability between different soils. Also, it is Zealand has a wide variety of parent materials this plant effect which results in the same soil and climate, and hence a wide variety of soils, having different levels of element availability for and already in its comparatively short agricultural different plants. history diKerences in supplying power of some Further along the chain, the grazing animal soils for cobalt, copper, molybdenum and selenium exerts its own impact by absorption and excre- have been linked with animal health. It may be tion, and possibly selectivity of grazing, so that that the comparatively uniform plant cover asso-

TABLE 4*5-1. Macroelements in Milk (from Four Soil Areas-North Auckland, Hauraki, Taupo, and Taranaki)

Wharekohe Silt Loam Hauraki Clay Taupo Sandy Silt Egmont Black Loam Element (North Auckland) (Hauraki) (Taupo) (Taranaki) mg/100 ml Mean Range Mean Range Mean Range Mean Range

Ca 133 126 147 121 105 145 140 132 150 129 93 151

- - - - Mg 12-0 10-9 14-6 10-9 8-1 13-8 12-8 11-4 16-0 11-9 7-9 14-1 - - - - K 162 147 176 145 124 165 169 151 178 160 126 180 - - - - Na 46 38 61 39 32 53 40 33 53 33 16 46 - - - - P 91 86 83 73 96 95 84- 102 88 66 -96 - -97

TABLE 4-5-2- Microelements in Milk (from Four Soil Areas-North Auckland, Hauraki, Taupo, and Taranaki)

Wharekohe Silt Loam Hauraki Clay Taupo Sandy Silt Egmont Black Loam Element (North Auckland) (Hauraki) (Taupo) (Taranaki) gg/litre Mean Range Mean Range Mean Range Mean Range

Zn 4, 000 3, 800 4, 400 4, 500 4, 300 4, 700 4, 000 3, 000 4, 900 4, 200 3, 400 4, 800 - - - - B 160 140- 170 167 150- 180 168 140-190 160 110-200 Mo 20 10 30 28 18 41 21 14 25 30 24 43

- - - - Co 0-4 0-3 0-5 0-3 0-3 0-4 0-5 0-3 0-8 0-3 0-3 0-4 - - - - Sn 2-5 2-0- 3-5 2-6 1-5 3*8 2-5 1-1 1-0 1-5 -3-5 -6-0 - Cd 0-9 0-4 1-4 1-0 0-8 1-3 1-0 0-5 1-8 0-5 0-5 0-6 - - - - Pb 10 3 34 8 3 22 10 5 24 5 3 10 - - - - Cr 0-3 0-3 0-3 0-3 0-3 0-3 0-3 0-3 0-6 0-3 1-7 - -0-5 - - Ni 1-3 0-5 3-5 0-5 0-5 0-5 0-5 0-5 0-7 0-5 1-0 - -0-5 - -

110 4-5

TABLE 4-5-3* Chemical Analyses of Matapiro Silt Loam and Ahuriri Clay Loam

Total Sul- Exchangeable Cations Sul- phate Truog phur Sul- - -- Depth Hori- pH CaCO, CEC TEB BS Ca Mg K Na C N C/N P phur in. zon % me% me% % me% me% me% me% % % mg% mg% mg% Matapiro silt loam 0 3 Axx 5-4 0 14-9 6-5 44 5-0 1-4 0-24 0-2 4-0 0-26 15 0-7 42 1-0

- 3-7An 5-6 0 12-7 5-3 42 4-0 1-30-12 0-1 2-70-20 14 0-5 30 0-9 9 - 13 As 5-9 0 9-2 5-3 58 3-4 1-7 0-09 0-2 0-6 0-06 10 0-2 n.d. 0-2 16-22 Bax 5-6 0 20-0 11-3 56 6-0 4-2 0-21 0-7 0-4 0-04 10 0-5 70 0-2

Ahuriri clay loam 0 3 As 7-0 0-8 n.d. n.d. n.d. n.d. 5*6 019 1-0 3-0 0-26 12 17 84 2-3 - 3 - 11 GCzz 7-7 1-7 n.d. n.d. n.d. n.d. 6-2 1-01 1-2 1-1 0-10 11 9 n.d. 5-6 12-20 GCx, 7-7 2-0 n.d. n.d. n.d. n.d. 6-6 1-60 2-0 0-9 0-08 11 8 216 42-8

TABLE 4-5-4* Total Soil Microelements in Matapiro Silt Loam and Ahuriri Silt Loam

Depth Hori- Al Zr Cr Ni Co Mn Mo Ga V Cu Ba Sr Ti in. zon % p.p.m. p.p.m. p.p.m. p.p.m. p.p.m. p.p.m. p.p.m. p.p.m. p.p.m. p.p.m. p.p.m. p.p.m.

Matapiro silt loam 0-3Aix 8-5250 20 2 <1300<1 8 40 121,0002501,400 3 7 A 10 270 13 2 1 270 1 7 45 9 1, 300 270 1, 000 - x, < < 4 9-13 A. 8 300 20 2 <1 200 1 10 50 1,500 500 2,000 16-22Bax 9 200 20 2 <1150

Ahuriri clay loam 0-3Ag 1120025 3

TABLE 4-5-5- Microelement Content of Tissues from Twin Wethers Raised from Pasture on Different Soils (All results in p.p.m. unless otherwise stated. Pasture, wool, bone-p.p.m. dry matter; liver, kidney, pancreas-p.p.m. fresh tissue. NOTE: Figures in italics represent well defined differences when twin wethers are compared.)

Soil Al Ba Cu Mn Mo Sr Ti Zn Si Co SO.% Fe Se

PASTURE Matapiro si.L 1,100 38 10 127 0-8 36 21 26 0-26 315 Ahuriri c.1. 700 6 10 35 6*6 29 15 24 0-47 200

Tissus Twin Raised on Al Ba Cu Mn Mo Sr Ti Zn Si Co SO, Fe Se

LIVER Matapiro si.l. 2-5 0-19 152 2-7 1*05 0-09 0-17 100 3-9 Ahuriri c.1. 3-0 0-28 33 2-1 1-50 0-08 0-47 70 4-7

KIDNEY Matapiro si.L 1-8 0-72 5-1 1-25 0-45 0-18 0-17 6-8 0-07 Ahuriric.1. 0-9 0-13 5-3 0-85 0-70 0-10 0-13 5-6 <0-04

PANCREAS Matapiro si.L 5*7 0-28 1-7 2-3 0-07 0-06 0-16 15 Ahuriric.1. 5-3 0-15 1-3 2-0 0-10 0*05 0-17 17

WOOL Matapiro si.l. 7-3 92 2-1 0*09 107 0*60 Ahuriri 8 103 0-4 0-22 133 0-35 c.1. -0

BONE Matapiro si.l. 215 4-6 0-15 320 38 Ahuriri c.1. 70 2-1 0 -85 290 30

111 4-6 ciated with the New Zealand system of grassland wool reflect the differences in pasture. Mean farming has helped to establish this linking of figures only are given here to emphasise the broad microelement supply with animal health. Molyb- trends since the full data making comparisons growth pairs lengthy be pub- denum has not only proved essential for the within are rather and will of clovers on a number of soils, but in association lished in full elsewhere. The figures given in italics with copper affects the grazing animal (Miller, represent well defined differences when twins are 1953; Cunningham, 1960). Cobalt and selenium compared. The complete data for twins also appear to be without effect on pasture growth suggest changes in copper content of certain but markedly allect animal health (Andrews, tissues under the influence of high molybdenum in pasture. 1961; Hartley et al., 1960). Factors influencing and sulphate levels the Selenium also is availability of these elements in certain soils are appears to differ when wool from twins com- discussed in Chapter 8. pared. given here Some current work at Soil Bureau shows the The summary material serves to impact of soils on animals via the pasture. This emphasise the impact of soil, especially in regard work arose out of studies on an association to microelements, through to the animal. The point possible between soils and the prevalence of dental caries results also to effects of increased in children in Hawke’s Bay (Ludwig, et al. 1960; fertiliser usage on microelement levels in animals, Healy, et al. 1961; Ludwig, et al. 1962) and was car- as soils continue to show up inherent, although provide informa- present in ried out not only to background at not obvious, weaknesses micro- project, tion on the soils-caries but also as a soil- element supply. plant-animal study in its own right. In this study, lambs and twin male were separated at weaning REFERENCES raised as wethers to the six-tooth stage, on the two Cobalt Deficiency in Sheep soils Matapiro silt loam and Ahuriri clay loam. ANDREWS, E. D. 1961: and Cattle. N.Z. Dep. Agric. Bull. 180. Analyses of soils (Tables 4 5 3 and 4 5 4) these - - - - CUNNINGHAM, I. J. 1960: Molybdate Topdressing and do differ show that total levels of elements not ap- Animal Health. N.Z. Dep. Agric. Bull. 378. preciably except for barium, and that the main HARTLEY, W. J.; GRANT, A. B.; DRAKE, C. 1960: Control Selenium. differences are in pH, CaCOz, exchangeable mag- of White Muscle Disease and Ill-thrift with N.Z. J. Agric. 101: 343-45. nesium, sodium, and sulphate sulphur. The high pH HEALY, W. B.; LUDWIG, T. G.; LOSEE, F. L. 1961: Soils Ahuriri high percentage of cal- of the soil and the and Dental Caries in Hawke’s Bay, New Zealand. Soil cium on the exchange complex as compared with Sci. 92: 359-66. LUDWIG, T. G.; HEALY, W. B.; LOSEE, F. L. 1960: An Asso- the Matapiro soil, markedly affect microelement IN dd availability, as can be seen from composition the sonn te7en aDen rees L :n6 6.Condi- pasture 4*5*5). Analysis data for of (Table various LUDWIG, T. G.; MALTHUS, R. S.; HEALY, W. B. 1962: An given in Caries tissues from the twin wethers is also Association between Soil Conditions and Dental inRats.Nature,Lond.,194:456-8. Table 4-5*5, and it can be seen that levels of M R,So B (Eld tor) 195Rep lyAdenum barium, manganese and molybdenum in liver, pMsdum kidney, pancreas and bone, and of manganese in denum Company, N.Y.)

4 6 SOIL EROSION AND CONSERVATION

- -

by H. S. Glass, J. D. RAESIDE, E. J. B. CUTLER, and W. A. PULLAR

INTRODUCTION Normal erosion is the removal of soil and rock materials under the native vegetation; where this Erosion is the process of removal of soil and vegetation had established an overall equilibrium rock materials; sedimentation is the comple- under which losses by erosion and wasting were mentary process of deposition of these materials. balanced by additions from other processes, the Erosion and sedimentation are included in the soil profile maintained an apparent uniformity. drift-regime group of soil-forming processes des- Naturally the rate of normal erosion varied with cribed in Chapter 2 2. The main effects are (1) - stage of the geomorphic cycle, being rapid in lowering of the land surface of uplands with a the youthful stages and decreasing with progress consequent continual incorporation of new rock maturity. Soil erosion is the accelerated materials into the soil via the subsoil, and (2) towards removal resulting from disturbance of the natural burial of former soils by deposition on lowlands. so soil is less effectively pro- The importance of these effects depends on the vegetation that the from frost rate of erosion and its deviation from normal. tected rain, wind, and than under the

112 4*6 native vegetation. Since soil erosion proceeds at soil and are described below in more detail ac- a greater rate than soil formation it will, unless cording to soil groups. checked, gradually destroy soil completely; on Soil erosion takes different forms which may protects (1) the other hand, where the new vegetation be classified according to movement as a mass particles, particles. Mass the soil more effectively than the native vegetation of and (2) as separate erosion is reduced and deeper soils are formed. movements include slow creep, rapid slip, and The native vegetation of New Zealand developed deep flow erosion of soil downslope under the gravity. gully, in the absence of man and large browsing animals action of Sheet, riverbank, and in except for some birds. Practically all of the North wind erosion are forms of movement separate Island, and northern, western, and southern parts particles. These forms may occur singly or in of the South Island were covered with forests up combinations such as sheet and creep or slip and grass- gully Descriptions differing forms to an elevation of about 5,000 ft. Tussock erosion. of these have been given by Campbell (1951) Taylor land was extensive on the eastern side of the South and (1962). A geographic discussion Island from Wairau River to south Otago, al- and Pohlen of is given (1944). though much of this region also had a forest soil erosion by Cumberland cover some centuries ago (Molloy et al., 1963). Dense tussock grassland and herbfields occupied SOIL EROSION ACCORDING TO the subalpine lands and in places the alpine lands SOIL GROUPS above the forest limit. Bare land or partly vege- soils occurred on sand dunes, river beds, tated Brown-grey earths and related hill and alpine lands and on patches exposed by and steepland soils natural landslides, debris avalanches, and earth- Soil erosion of brown-grey earths of semi- flows. Some mass movements were initiated by the arid inland basins of Otago and Canterbury earthquakes or severe storms, and others took (Conroy and Alexandra soils) began soon after place when a tree grew too heavy for the soil to native and shrub growth was burned hold on slope (Wright and Miller, 1952). the tussock the grazing. to produce fresh growth for sheep Under Maori tribes made only small changes to normal the low annual rainfall of 14 to 22 in. with frequent erosion with their cropping, but from time to frosts, regrowth of grassland was slow time they started huge fires, in forests and in tussock and after the fires the soils were bared to frost, tussock grassland, that bared large areas to wind rain, and wind for long periods. Topsoils were and water erosion. On many soils this erosion very friable sandy loams or silt loams with a was slight before it was checked by the regrowth weakly developed crumb or platy structure and of vegetation unhampered by grazing. More severe were easily eroded. After repeated burning losses were probably seen in the extension of sand the and grazing, sheet and wind erosion became wide- drifts inland from the coast and of screes down spread; Gibbs and Raeside (1945) estimated that hillsides in the subalpine to alpine areas. In these of 450,000 acres* of soils 356,000 acres localities soil formation had only recently brought the these were severely to extremely eroded and 45,000 acres some degree of equilibrium to the drift regime, slightly moderately eroded. They concluded and rates of plant regeneration were slow. to place that most of this erosion had taken by the European settlement after 1820 brought ploughs, end of the 19th century and from then on con- axes, and numerous grazing ammals- to make big tinued at a slower rate. Although rabbits were changes in the organic regime. Large tracts of blamed, erosion had begun before their introduc- forest were burned and the land sown in pasture; and merely intensified depletion of grassland tion they the similar- of were burned tracts tussock and so increased erosion. Many graze young growth; the vegetation the and sheep were sent to the areas of steepland (Alexandra soils) are still bare rolling and plains lands were ploughed for the and are being further wind and sheet eroded. same crops year after year. Erosion on all these Narrow gullies have developed on some concave soils was accelerated. On some it was soon checked slopes and are removing all soil down to the by grassland, under which the previous soil losses underlying rock. were gradually replaced. On others the readjust- On eroded terrace lands (Linnburn and Drybread ment of organic regime was more difficult, the soils) irrigation and improved dryland farming but, in time, stability was achieved with the have reduced soil erosion and begun the rehabilita- assistance of fertilisers and careful management tion of soils. To a lesser extent this is also true of for cereal cropping, grazing,- or forestry. On others the soil was rapidly removed exposing rocks on on a h which formation of new soil has been very slow. I nd en coilereducalbparhteofhth The effects of soil erosion differ with kinds of are given in Chapter 4-1.

113

H 4-6 the rolling and hilly slopes and on lower parts of aggregates of the topsoil are easily powdered by steep slopes as a consequence of aerial topdressing, repeated cultivation and the surface layer can be oversowing, and controlled grazing. On steep- removed by high-intensity rains or strong winds lands, the erosion has increased the naturally at any time of the year. Sheet and wind erosion serious limitations on plant growth set by dryness were particularly serious before 1935, when crop- and wide fluctuations of temperature. These slopes ping was widespread, but since then have greatly should be completely withdrawn from grazing so decreased with the change to mixed farming, that they can be recolonised by plants. In this which has been accompanied by improved manage- way more rainwater will be absorbed and thus ment to increase soil structure and fertility. delivered more slowly to streams. Most of the Isolated cases of sheet and of wind erosion may present grazing is by wild rabbits: the immediate still be found each year as a consequence of response in greater plant growth that took place injudicious cultivation or an unusual storm. after the intensive period of rabbit destruction in The bill and steepland yellow-grey earths are the late 1950s demonstrated how a cover of sown in permanent pasture, and soil erosion vegetation could be obtained fairly rapidly on the consists mainly of slips with local patches of sheet brown-grey earths. erosion and subsequent gully erosion (Pohlen et al., 1947). Slipping is most common during or im- Yellow-grey earths and related hill mediately after heavy rain in summer or autumn, and steepland soils chiefly on the soils derived from weakly consoli- Yellow-grey earths of subhumid regions of the dated sandstones and mudstones (Crownthorpe inland basins of Marlborough, Canterbury, and and Atua soils), which under grazing become Otago (subclass A of southern yellow-grey earths) compacted when moist and fissured when dry. erode in a similar manner to the brown-grey The fissures intercept rainwater and lead it into earths. However, the extent of the soil erosion is the subsoil, where it seeps away. Where the less and was estimated by Gibbs and Raeside seepage follows a marked junction within the (1945) as 516,500 acres severely to extremely soil or between soil and rock material, it lubricates eroded and 1,201,000 acres slightly to moderately a plane along which the overlying block of soil eroded out of a total area of 1,944,000 acres.* may slide away when the friction is sufficiently This lesser degree of erosion is attributed to the reduced. The frequency of slipping has been in- effects of higher annual rainfall (20 to 35 in.) in creased both by the extra drying and cracking of promoting deep topsoils with friable moderately the surface soil under grassland and by the replace- well developed aggregates and in promoting more ment of deeply rooting trees by dominantly rapid regrowth of plants after depletion. Sheet and shallow-rooting grasses. In many of these soils wind erosion have removed topsoils from many the material exposed by slipping weathers rapidly ridges and convex sunny slopes but less commonly and soon develops a new soil on which pasture be loss is from concave or shaded slopes where the soils may established. Hence the of soil not receive or retain more moisture and can maintain permanent, but the debris raises river beds and a dense growth of tussock grasses. With careful increases flooding and sedimentation in lower management the flat and easy rolling lands (Oture- reaches of streams and rivers. Where this can be hua and Cluden soils) can be safely used for tolerated, these soils may be suitable for permanent mixed cropping and pastoral use. The soils on pastoral farming. The frequency and intensity of rolling, hilly, and steep lands (Blackstone and drying and associated cracking should be lessened Ngapara soils) are suitable for dryland pasture by topdressing and careful management to maintain farming with assistance from topdressing and a dense grass sward and associated fine granular avoidance of overgrazing. soil structure. Spaced planting of selected trees On the extensive areas of yellow-grey earths may also assist stability. along the east coast of New Zealand (subclasses In associated soils formed from bentonitic B and C) the native tussock grassland, fernland, mudstones (Wanstead soils) rainwater entering down joints in or broadleaved forest has been completely re- the cracks may continue through planes placed by pasture grassland. In most places the the soft rock to deep shear along which conversion took place fairly quickly, with only a soil and rock move downslope in a series of small amount of soil erosion. However, cultiva- slumping movements, some of which are on tion of many of the soils of plains and downlands slopes of low angle. These deep slumps are beyond (e.g. Lismore and Timaru soils) led to periodic the control of grasses alone, and tree planting sheet and wind erosion. The crumb and nutty and diversion of drainage are required to lessen the rate of slope movement. Erosion on these is problem *See footnote p. 113 soils a serious to maintenance of roads

114 4*6 and railways, which should be located elsewhere vegetation and so extending the soil erosion. if possible. Natural plant regeneration on higher slopes is grazing goats, A combination form called tunnel-gully erosion also being delayed by of deer and be The occurs on hillsides of yellow-grey earths in drier which should reduced to a minimum. fine parts of Wairarapa, Marlborough, and Canterbury soil removed during the early stages of erosion did lowlands, (Gibbs, 1945). In these places water running down little damage to farms and roads on the fissures formed by severe drying erodes tunnels in but the stony debris from the later stages is build- the underlying loess beds. In time, enlargement ing up the beds of river channels and causing South of the tunnel causes the overlying soil to collapse destructive floods on the east coast of grazing and to produce a gully. Once this form of erosion Island. This will continue whilst of steep- yellow-brown is per- is visible it is far advanced and difficult to control. land high country earths It must be prevented in the early stages by main- mitted, tenance of dense pastures to avoid the severe drying out and deep fissuring. Southern and central yellow-brown earths and related hill and steepland soils High country yellow-brown earths The southern and central yellow-brown earths in High country yellow-brown earths are very are very extensive the mild humid regions broad- extensive in the cool humid montane regions of where the native vegetation was mixed South Island where the native vegetation was tall leaved-podocarp forest. Replacement of most of grassland tussock grassland or mountain beech forest. Prac- the forest by has widened the moisture greater drying tically all the tussock and forest on these soils range of the soils and caused out (Taylor, 1938). The has been burned to allow grazing, but the re- of the surface consequent generation of tussock grasses was slow and most network of shrinkage cracks, and the weaker root pastoral farming, of the introduced grasses failed to establish, bonds in the subsoil under hilly primarily because of low nutrient fertility. The increases the rate of slip erosion on soils of soils are friable silt loams, which have shallow and steep lands derived from soft mudstone and granular and permeable topsoils over stony and sandstone sediments in a similar manner to that yellow-grey begin very strongly leached subsoils. When these soils on the earths. Many slips after are bared to frequent frost heave and solifluction, road excavations or stream erosion undercut a is from block roots are broken, and the surface soil loosened slope and remove support the of soil Each so as to be easily washed or blown away. Repeated immediately upslope. of these slips tends to headward losses leave a surface of stony debris that combines be followed by a succession of slips to form long screes down the hillsides. On concave from the first one. Also, on many of these soils, and lower slopes where rain wash collects into surfaces are wet in winter and stock trampling streams, large gullies are gouged out of the stony develops a series of narrow terraces. Shrinkage formed back pro- colluvium. All these soils have been seriously cracks at the of these terraces eroded. A survey made in 1942 (Gibbs and Raeside, vide initial conditions for subsequent slip erosion 1945) showed that three million out of four of a soil block immediately below the terrace. yellow-brown million acres of Kaikoura steepland soils* had The slipping on many of these yellow-grey lost more than half of their topsoils. On the earths is more serious than on the has lower terrace and rolling lands (Tekapo and Cass soils) earths, because the exposed surface a grasses in- the estimates of 238,500 acres moderately to fertility for and is liable to vigorous Farmers severely eroded show that erosion was less rapid vasion by shrubs and ferns (Taylor, 1938). face demands light grazing for but none the less serious. the conflicting of pasture grazing for The frequently low temperatures and very low regeneration and heavy weed levels of nutrients of high country yellow-brown control. With weedkillers, close subdivision against earths are serious limitations to plant growth, weed invasion, topdressing, and stock manage- pasture, and grazeable replacement plants for tussock ment to build up surface fertility for grassland are difficult and costly to establish. soils formed from mudstones and calcareous sand- have Some success with cocksfoot and clovers has been stones (Pahiatua and Mahoenui soils) attained farming This obtained on the easier sloping lower lands, where an equilibrium under conditions. better pastures would accommodate all the sheep equilibrium is easily upset by an unusual season it is of the high country. Light grazing by these sheep or change of management, more easily main- lands farmed with on the steeper and higher slopes (Kaikoura and tained when of easier slope are Tekoa soils) is continuing the depletion of the the steeplands. There is no significant erosion under grassland on the associated yellow-brown earths land Korokoro *See footnote p. 113. on rolling (Waikiwi and soils).

115 On steepland soils formed from hard sandstones and when the soils are deprived of their covering or argillites (Whangamoa and Ruatoria soils) of decomposing litter they suffer rapid run-off the establishment of equilibrium under pasture and sheet erosion of their shallow topsoils. Slip would require large amounts of fertiliser. Much erosion, also, results from increased drying-out less effort is required to establish an equilibrium of the soils. The clay subsoil exposed by sheet or under forest, for which use the soils are at present slip erosion is low in plant nutrients and has a considered to be more suitable. Hill and steepland dense surface on which it is difficult to establish soils formed from soft argillites and bentonitic and maintain pastures. With lime, phosphate, and mudstones (Whareama and Tuparoa soils) have potash, dense pastures can be obtained to protect moderate to high fertility for pastures, but are the soils from erosion. But these treatments are susceptible to severe slip and gully erosion, against suitable only on the rolling and moderately steep which grasses are impotent. Such soils should be land (Waiotira and Marua soils). On the steeper permanently protected with forest until methods hills most of the soils are more suited to forestry. of ensuring stability are found (Grange and The steepland areas (Te Ranga soils) are small, Gibbs, 1947). and with a forest cover they conserve water supplies Yellow-brown earths developed from hard grey- that are required for the adjacent farm land. wacke or limestone under mull-forming broad- leaved forests (Makara soils) or short-tussock Podzolised yellow-brown earths, podzols, grassland (Hurunui soils) have a deep nutty- and related steepland soils gradually becomes granular structured topsoil that Under natural conditions the podzolised yellow- under grassland. Rainwater is absorbed evenly, brown earths and podzols have a thick mor grassland and equally as well under the as under humus, which protects the underlying mineral forest, grassland the native and erosion under the soil against erosion. This humus mat is a main is limited to a few shallow slips, usually situated source of plant nutrients, and it contains many hillsides. These above seepage sites on soils can tree roots. Any disturbance of the mat by removal pasture attain a satisfactory equilibrium under of trees or by cultivation exposes the soils, which land for pastoral and so make excellent or timber can then be eroded rapidly. On rolling and un- production. In contrast, the soils developed from dulating land (Tautuku and Wharekohe soils) greywacke, but beech similar under mor-forming localised sheet erosion occurs during the estab- forests, failed pastoral have largely as lands. lishment of dense pasture and may begin again if Topsoils are shallow silt loams or clay loams that pastures are depleted. The amount of such erosion grazing under become compact, increasing the in New Zealand has been small, and the losses loss run-off and of topsoil (Taylor, 1938). This have been gradually replaced under permanent poor sheet erosion exposes a subsoil with a struc- grassland. Not so, however, on the hilly and steep low Under ture and supply of nutrients. these lands (Denniston and Haast soils), where the is for grasses, conditions the fertility inadequate sheet erosion is more rapid and pastures are much by fern, gorse- and slopes are invaded manuka, and more difficult to establish and maintain. On the Burning plants these only increases the oppor- few areas where pastoral use has been attempted, tunity for sheet erosion, and the soils are better sheet erosion has so increased the problems of left forest planted for to regenerate or timber establishing grassland that practically all of the The be heavy supplies. alternative would top- cleared lands have been abandoned to second- dressing, close subdivision to control second growth forest. The soils on these hilly and steep growth, build fertility. and management to up lands require the mor-humus protection that they Above 1,000 ft the soils are more stony, the re- obtain under forest or shrubs. Commercial forestry generation is of vegetation slow, and attempts to may be possible on some of the hilly lands, but pasture have failed prevent establish to rapid soil permanent protection forests are required on the erosion. On the steepland soils (Bealey and Rimu- steep lands, and permanent alpine vegetation above forest be taka soils) should retained to conserve the altitudinal limit of forests. Slips and debris flooding soil and water and to reduce and sedi- avalanches are natural phenomena on these lands, flood plains. The forest is mentation on the cover and the rebuilding of soil with the protective mor depletion by deer, goats, susceptible to and opos- takes many years even in the absence of animals. populations sums, and of these animals must be Introduced animals, particularly deer and opos- kept to a minimum. sums, have invaded large areas of these soils and have so depleted the undergrowth and litter yellow-brown Northern earths horizon under beech forest that considerable sheet The northern yellow-brown earths were mainly erosion has occurred. In some places this sheet developed under mor-forming podocarp forest, erosion has been arrested by the development of

116 4-6 a less palatable understorey of plants. In other of Hawke’s Bay severe wind erosion exposed rock parts, combined browsing by deer, goats, and that remained bare for many years. The danger is opossums has led to gully, slip, and scree erosion obvious and is now carefully avoided during de- and destruction of the forest itself (Holloway, velopment of pumice lands. 1962). Land in the zone immediately below the line is depletion timber most susceptible to of the Yellow-brown, and red and brown loams loss The vegetation and rapid of soil. effects are and related steepland soils well described by Druce and Atkinson (1956) and The high permeability and moderately developed unless checked will have serious consequences on structure of the yellow-brown and red and brown water supplies as well as intensify flooding of loams make them only slightly susceptible to soil lowlands. erosion under conditions of usage in New Zealand. They are readily converted from forest to grasslands Rendzina and associated soils but if used repeatedly for cropping may suffer Soil erosion on the rendzina and associated wind and sheet erosion. soils is limited to slight sheet erosion on some frequently cultivated lands and slight slip erosion Brown granular loams and clays, and on overgrazed hillsides. The strong structure and related steepland soils moderate to high fertility of these soils are natural The brown granular soils are generally less deterrents to soil erosion. permeable and less fertile than the associated yellow-brown or red and brown loams. The soils Yellow-brown sands developed under tussock grassland in the South All of the yellow-brown sands are susceptible Island (Camphill and Middlehurst soils) erode to wind erosion when the surface is exposed. Only slowly when exposed and, by appropriate However, decreases this susceptibility with the management to avoid the moisture limitations to greatest in degree of soil development, being the fertility, can be used for mixed farming. However, dune (Kairaki earliest stages of stabilisation and the soils developed under forest or from ultrabasic Foxton soils) and least on the older and more rocks (Cargill and Dun soils) are difficult to con- weathered sands (Riverton and Red Hill soils). vert to grassland without serious sheet erosion. On plains soils of sand where the subsoil remains This difficulty applies particularly on hilly and moist there is little or no loss by wind erosion. steep lands (Waimatenui and Te Kie soils) where Detailed descriptions of the effects and extent of dense swards are slow to establish and, in the yellow-brown soil erosion on the sands of the interval, sheet and some slip erosion may remove district given Manawatu are by Cowie (1958). large slices of the topsoil. Wind erosion of topsoil occurs on some coastal lands. With careful manage- Yellow-brown pumice soils and related ment the soils on rolling land can be used for grassland, but leached hilly steepland soils the more soils of the and steep lands may be better used for The pumice soils are porous and under either timber under which need be little soil forest or dense grassland suffer little erosion. trees, there erosion. Even when the vegetation is depleted by logging or grazing there is little increase in run-off until an gley, gley intense rainstorm exceeds the limit of percolation Organic, saline recent, and recent soils into the surface soils. Then the run-off may remove The organic, gley, saline gley recent, and recent loose topsoil rapidly and carve deep ravines in soils are formed from alluvium on low-lying lands the soft volcanic ash. The frequency of such catas- that are still subject to inundation with sediment trophic erosion is increased by the compaction unless protected artificially. Shallow deposits of and sealing of the surface by trampling. The in- fine-textured sediment can be an advantage and stability of these soils (Taupo-Kaingaroa soils) can be fitted into the management of lands increases with slope, and the hilly and steep bordering stream channels and lakes. But thick lands may be better used for timber production, deposits and coarse-textured sediments are harmful for which they are excellent. Under forest the and should be avoided by conservation measures dangers of widespread erosion can be minimised in the upper catchments. Otherwise they should by strip felling. be diverted to infill unused swamps or deltas. The pumice soils are very friable to loose and Losses by erosion are principally through bank are susceptible to rapid wind erosion if the vege- erosion, which is a natural process requiring tative cover is destroyed by cultivation or extensive engineering protection where the erosion endangers burning. During the development of western parts valuable soils or settlements.

117 4-6

On the recent soils from volcanic ash, slight accommodated on associated lower and easier gully, wind, or sheet erosion occurs if the colonis- slopes on which good pastures can be obtained by ing vegetation is disturbed by animal browsing oversowing and topdressing. The deer, goat, and or by fire. These soils are best left under native rabbit populations should be reduced to a mini- vegetation so that topsoils may increase in clay mum and kept under strict control. content and develop the structure needed to resist Soil erosion was not created wantonly but was soil erosion. usually an unforeseen effect of human efforts to obtain a living from the soil. The early settlers had to deplete the vegetation for this purpose, SOIL EROSION AND THE COMMUNITY and some accelerated erosion was inevitable during Historical records and surveys show that soil readjustment of the soil-vegetation equilibrium. places period erosion has been widespread in New Zealand since In many the of readjustment was prolonged by lack knowledge properties the expansion of European settlement after 1850 of of soil farm (Committee of Inquiry, 1939). Between the removal or of means of management to maintain of forest and establishment of pastures on most soil structure and an adequate cover of vegetation. But destructive of the yellow-brown loams, yellow-brown pumice awareness of the effects of erosion soils, and lowland yellow-brown earths of rolling and the insecurity that it brings to the district gradually spread from farmers general lands losses of soil were small, and topsoils are to the Soil a loss now generally deeper and more granular than they community. erosion means not only farm but loss productivity were under the native vegetation. Where these to the owner a of to district, for soils or the yellow-grey earths and associated the an extra tool the stream to scour its banks, deposit stony and shallow soils were cultivated repeatedly, or an unwanted on another farm in Aware- layers of topsoils were periodically removed by or a reservoir or shipping channel. wind or sheet erosion. This erosion continued ness of the extensive effects of soil erosion spreads but it is until permanent grassland was established or very slowly, now well recognised that incompatible until modern methods of mixed farming, using soil erosion and communities are flourish Per- fertilisers were adopted, and soil losses are now and cannot continue to together. in past has decline infrequent and small. Clearing the forest from sistent soil erosion the meant hilly and steep land accelerated mass movements of both soil and the community. On the other gives of soil, and this has been more difficult to control hand, stability of soil through conservation firm basis for progress. This is fully than wind and sheet erosion. On the less fertile a concept by Soil Conservation yellow-brown earths and podzolised soils the encouraged the work of the losses were so frequent and exposed surfaces so and Rivers Control Council and district Catch- both slow and difficult to regrass that pastoral farming ment Boards. They subsidise repair and prevention farms, help farmers had to be abandoned in many places and the land of erosion on and in join in returned to forest. Losses were more rapidly small catchments to together overall Their replaced on the hill and steepland yellow-grey conservation schemes. contributions to soil earths and more fertile yellow-brown earths where conservation are financed by townspeople as well pastoral farming has persisted. Although some as country people and demonstrate the national link between progress in lessening the mass movements has acceptance of the the soil and the people New Zealand. been achieved through topdressing and grazing of management, more investigations are needed to bring soil losses down the to the rate of soil REFERENCES formation. Little progress in controlling erosion in has been made on the high country yellow-brown CAMPBELL, D. A. 1951: Types of Soil Erosion Prevalent Un.Bgdod, J int., Ass. int. Hydrol. earths and associated yellow-grey and brown-grey "AZealand. earths. Here sheet, wmd, and scree erosion are 9yt Committee of Inquiry, 1939: The Maintenance of Vege- have little still widespread and shown slackening tative Cover in New Zealand with Special Reference Land Erosion (Report). N.Z. Dep. industr. Res. over the last 40 years. Much has been written and to sci. Bull. 77. 51 pp. recommended but little has been done to lessen it Coo SdilG d gricul re and so prevent it from causing damage on the O ’uPD w s, ail ol958* lowlands of Canterbury and Otago. The first tricts, Manawatu County. N.Z. Soil Bur. Bull. 16. 56 pp. requirements for erosion control are that indis- CUMBERLAND, K. B. 1944: Soil Erosion in New Zealand. Whitcombe Tombs, Wellington. 227 pp. criminate burning of tussock should cease and and DRUCE, A. P.; ATKINSON, I. A. E. 1958: Forest Variation that grazing be reduced to allow existing plants m the Hutt Catchment. Proc. N.Z. ecol. Soc. 6: 41-5. to regenerate and new ones to be established. GIsas, H. S. 1945: Tunnel-gully Erosion on the Wither The sheep from the eroding steeplands could be Hills, Marlborough. N.Z. J. Sci. Tech. A27: 135-46.

118 4 -7

GIsas, H. S.; RAESIDE, J. D. 1945: Soil Erosion in the High Remains, Eastern South Island, New Zealand. N.Z. J. Country of the South Island. N.Z. Dep. sci. industr. Res. Bot. 1: 68-77. Bull. 92. 72 pp. POHLEN, I. J.; HARRIs, C. S.; Glass, H. S.; RAESIDE, J. D.

GR Erosion in New huHj dnH we aSONeZ.R c / o BI .r dL.NM. Ill9147bSo)il 176 pp. eP 91 HOLLOWAY, J. T.; WENDELKEN, W. J.; MORRIS, J. Y.; TAYLOR, N. H. 1938: Land Deterioration in the Heavier WRAIGHT, M. J.; WARDLE, P.; FRANKLIN, D. A. 1963: Rainfall Districts of New Zealand. N.Z. J. Sci. Tech. 19: Report on the Condition of the Forests, Subalpine- 657-81. scrub Lands and Alpine Grasslands of Tararua Range. the TAYLOR, N. H.; POHLEN, I. J. 1962: Soil Survey Method. N.Z. For. Serv. Pap. 41. 47 pp. tech. N.Z. Soil Bur. Bull. 25. 242 pp. MOLLOY, B. P. J.; BURROWS, C. J.; Cox, J. E.; JOHNSTON, WRIGirr, A. C. S.; MILLER, R. B. 1952: Soils of South-west J. A.; WARDLE, P. 1963: Distribution of Subfossil Forest Fiordiand. N.Z. Soil Bur. Bull. 7. 31 pp.

4-7- TOWN AND COUNTRY PLANNING

by J. W. Cox

Town and Country Planning Branch, Ministry of Works

INTRODUCTION search took place within three years of each other Perhaps was indicative of end of Information about soils is an important feature this the the pioneering period and the beginnings of an era of the basic survey data required for town and of conservation. Unfortunately almost at once, country planning. In New Zealand it is of special progress in planning became seriously significance because our productive soils assisted town affected by the depression and, later, full recogni- by a favourable climate are by far our greatest tion was again retarded during World War II natural asset. In Government there is a very close by preoccupation with events overseas. association between the Soil Bureau of the De- partment of Scientific and Industrial Research and the Town and Country Planning Branch of URBAN INDUSTRY AND EXPANSION the Ministry of Works, which is responsible for POPULATION providing much of background data used by the The late 1930s and early 1940s ushered in two local authorities in preparation of the the their . significant changes, which were largely unnoticed planning In planning schemes. town the soil greater proportions until they assumed even after scientist is called in on such questions as soil the war. The first was the growth of urban indus- mechanics and the drainage properties of the try following the imposition of tariffs and import soils especially in relation to the disposal of restrictions. This was later intensified by the cutting sewage and other wastes. But it is in broad the imports of war. The other planning off of as a result the field of town and country where our most growth, was the very high rate of population productive soils are under constant threat from which has since been maintained until today it urban expansion, that close and continuous represents an annual increase of about 50,000. collaboration is vitally necessary. This surge of new population and the needs of rehabilitation of soldiers have made heavy de- EARLY DEVELOPMENT mands on usable land. On the credit side, they State, for Until comparatively recently, there was little sparked off a great drive, mainly by the public realisation of the seriousness of the problem the development for pastoral farming of hitherto of urban sprawl. Towns had been either small neglected land. For example, since the war, opera- clusters around the main ports, or local settle- tions by the Lands and Survey Department on the plateau ments providing little more than a service to the pumice soils of the central volcanic of farmers in the neighbourhood. Possibilities of North Island have been responsible for bringing per farming expansion appeared boundless. After into production some 20,000 acres annum. World War I, however, uneasiness about the Partly owing to this new farm development, but haphazard use and development of land gradually more particularly because of the general adoption greater gave rise to public pressure for more enlightened of better farming practices and the use of policies. The first Town Planning Act was passed machines, primary production continues to in- year. however, in 1926, and it is of interest that the appointment crease each Despite this, the de- of the first Director of Town Planning and the numbers engaged in primary industry have separate establishment of a Soil Survey group in creased since the end of the 1930s. This means population is the Department of Scientific and Industrial Re- that the annual increase almost

119 4*7

exclusively urban; it is, in fact, absorbing some made for this information to be supplied to all thousands of acres of farmland every year. planning authorities from data obtained from This is a problem that New Zealand shares Soil Bureau. Although maps showing soil types with many other countries, but two special aspects were the starting point, they needed to be inter- in this country make it of vital concern to the preted for the benefit of the layman in terms of economy: the first is the very low residential potential fertility. For the planner engaged in the densities arising from the almost universal develop- preparation of a scheme, or in evidence on an ment of the detached house on its individual appeal, this needs to be expressed in some com- section. The other is the fact that most of the parable measure of production per acre. This, of towns are located or are expanding on limited course, is by no means constant. Quite apart from good areas of arable land. Some idea of the the vagaries of the local market and the changes gravity of this threat to the economy can be of emphasis in overseas trade, recent rapid advances appreciated from the accompanying map (Fig. in farming techniques, and in soil science as such, 4-7-1), which shows the main cities and towns have transformed our previous understanding. superimposed on the main areas of good plough- Consequently, planning arguments can be advanced able land. The shortage of good arable land is even only in the light of the closest collaboration with more strikingly revealed from the air. The inland the soil scientist and the agricultural economist. provide air routes extensive panoramas of moun- Fortunately, in this country all three work to- tains, bush, and scrub-covered hills, and limited gether in close harmony in an atmosphere of areas of grassland: by comparison the areas of mutual respect. arable land are extremely small. In a wide range of cases involving the conflict- ing claims of urban and rural interests the Town and Country Planning Appeal Board has consistent- TOWN AND COUNTRY PLANNING ACT ly upheld the basic conservationist principle of Legislative recognition of the need to conserve the Act. In most instances two complementary pro- the good soils for primary production was not questions are at issue: on the one hand the obtained until 1953 when the Town and Country ductive capacity of the land which is the subject question Planning Act replaced the Town Planning Act of appeal, and on the other the whether 1926. The change in the title was reflected in the subdivision of the land is justified, having regard extension of land-use control over the whole to the capacity of existing planned urban areas country. Counties were required to prepare plan- to absorb additional population. Nearly always, ning schemes for their development in the same convincing evidence can be brought on both way as urban authorities. The Government, counts. When expansion of existing urban areas through the Minister responsible, the Minister is proved to be necessary, however, it can usually of Works, could intervene not only in respect of be directed onto soils of lesser value. This some- questions planning problems public works but also in that affected the times involves complex and public interest and the national welfare. Procedures major long-term decisions on land use that should safeguarded democratic rights to object, with final really be made at the regional level. resort to an independent Town and Country On the Heretaunga Plains in Hawke’s Bay, for Planning Appeal Board whose responsibility was example, the County Council has for some years to resolve conflicting claims for the use of land in firmly opposed the expansion of Hastings over its accordance with town and country planning existing boundaries while offering as an alternative principles. The Act and Regulations laid down the the establishment of a semi-satellite development principle that every planning scheme ’shall provide on land of lesser quality in the Irongate area, a as far as is practicable for all land of high actual mile or so beyond the city’s western boundary or potential value for production of food to be (Fig. 4-7-2). Hastings is located in the middle of included in a rural zone, for the avoidance of the Heretaunga Plains on soils that can be ranked encroachment of urban development on that land, with some of the best in the world. With the and for the concentration of urban development establishment of fruit and vegetable canning and within existing urban areas in preference to ex- deep-freeze factories, much of the plain is already pansion of urban development into rural areas’. used for intensive production. Annual returns In practice the administration of this require- from market gardening can average over £500 per ment of the Act turns on the precise definition acre. Judged from the accompanying soil-fertility of what is ’land of high actual or potential value map, therefore, the County Council’s argument is for production of food’ and equally as precisely irresistible. With industry located between existing on where it is located. Basically, this is a question Hastings and the Irongate area on a shingle strip, for the soil scientist. Arrangements were therefore formerly the bed of the Ngaururoro River, the

120 4-7

Kaltaia 1(alkohe

Whangarel

Dargaville

Warkworth

Helensville

Auckland Manukau Pukekohe

Te Aroba Tauranga Morrinsville Te Puke n Whakatan CaH Te Awamutu 0 Otorohanga

Te Kulti

Gisborne New Plymouth Warroa

Stratford

Elt aamera Napier

Patea Hastings

Wanganui Walpawa Marton Walpukurau Feliding Dannevlrke Palmerston North Woodville Pahiatua Levin

OtakI Takaka Masterton Carterton Motueka Featherston Nelson

BlenheIm

Lower Hutt Westport

Greymouth

Good ploughable land Christchurch

8 Cities

Ashburton e Towns

TimarU 10 0 10 40 60 80 rnlles

n-. - r-.

Oamare

Dunedin

Mostlei

invercargill Gore

FIG. 4-7-1- Location of main population centres of New Zealand in relation to good ploughable land (modified after in map accompanying ’Report of the Royal Commission to Inquire into and Report upon the Sheep-farming Industry New Zealand’, 1949. Govt. Printer, Wellington).

121 4-7

SOIL FERTILITY

. Very high to excellent

Medium to high

NAPIER

TAR A DA LE

IRONGATE AREA

HASTINGS

HAVELOCK NORTH

SCALE

4 3 2 1 O 4 MILES

FIG. 4-7-2* Heretaunga Plains-soil fertility.

proposal makes good sense also from the viewpoint urban development this would mean the loss to of urban planning. Yet it was initially opposed by production of not less than a further 1,000 acres urban interests whose future prosperity is inex- of highly fertile soils, which are in short supply tricably bound up with the preservation of the in Otago. The Appeal Board ruled against the rich soils of the plains. Better counsels have since proposal and recommended that expansion of prevailed, but in the interim it was decisions of the urban nucleus of Mosgiel should be towards the Appeal Board that held the pressures in check. the hills, with industry so located as to exercise a A similar issue arose in 1961 from a proposal pull in this direction, where also the main road for industrial development on Taieri Plains near and rail routes are situated. Dunedin. The proposed location of 50 acres of In such cases as these the evidence of the pro- industry in the middle of the plains would have ductive capacity of the soils is usually the decisive led to urban settlement around it. On the basis factor. of the normal ratio of industrial land to total If there is confusion of thought on these issues

122 4-7

background it usually arises from the diverse interests of the that is required by the Act as a factual planning urban and rural local authorities responsible for for the preparation of the regional planning decisions. Questions of any magnitude scheme. This work, which is part of the National involving conflicting claims to the use of land can Resources Survey, is being undertaken by the be resolved only in the light of a much broader Town and Country Planning Branch of the perspective, which is at least regional in context. Ministry of Works, and so far regional surveys Local authorities cannot reasonably be expected have been published for the West Coast, Bay of to decide such questions. It is not part of their Plenty, Marlborough, Northland, and Nelson, administrative responsibility. This can also be and surveys for Otago and Hawke’s Bay are true of metropolitan authorities where their well advanced. Each contains a section on soils, prepared Soil Bureau. boundaries are too tightly drawn, no matter how in close collaboration with precede much mutual benefit the individual local authori- Ideally regional schemes should the ties may derive from preparing an overall develop- district planning schemes of the constituent local ment scheme together. The administrative res- authorities but, as there are no regional schemes ponsibility is still too narrowly urban. outside the main metropolitan areas, most of the prepare district Clearly there is an urgent need in New Zealand local authorities have had to their guidance. for regional planning authorities with a much schemes without regional In those cases wider territorial responsibility. Legislation pro- the best available soil information has been viding for their establishment and procedure, supplied as part of their planning survey data. in which now forms part of the Town and Country While this material has been used effectively Planning Act 1953, has been in existence since the preparation of district schemes and in the 1929. Yet little advantage has been taken of it determination of objections and appeals, its full greater production except in the four metropolitan areas where its value as a stimulus to and the main purpose has been to draw together the more discriminating use of land must await the multitude of local authority planning schemes into broadening of administrative responsibility into a cohesive whole. However there are encouraging the regional field. Meantime decisions on urban signs of a rapidly increasing appreciation of the development affecting the conservation of soils importance of regional planning to the economy. tend to be made in the light of the immediate local Regional planning authorities have been estab- circumstances rather than the needs of the future. lished in Northland and Marlborough, and steps But, however we may view our responsibility to are being taken to set up regional organisations posterity, the fact remains that when we develop in several other provincial areas. The Government land for urban purposes we have made a decision land has also undertaken to compile the comprehensive that our successors cannot revoke. That can production. survey of the natural resources of each region never be returned to farm

123 CHAPTER 5. SOL CLASSIFICATION FOR LAND USE

by H. S. Gmas

5-1* INTRODUCTION

Classification of soils for land use is one of the they are concerned with particular parts of a soil principal objectives of soil investigations. To many rather than the whole soil. Hence man is treated people it is important the most one because they separately although he is the most important are more interested in the uses of soils than in the factor in increasing soil productivity. soils This motive is demonstrated themselves. In the second stage the characteristics of the history in kinds throughout the of soil classifica- soil units are interpreted in the light of land-use by Chinese Egyptian peoples, tion made ancient or experience on individual soils. This experience is by Maori European pioneers in New and or collected from farmers, foresters, agricultural Zealand. All classifications based the early were scientists, experimental trials, and the field ob- how on well uses were adapted to soils, and the servations of the soil surveyor. It is recorded alternative of adapting soils uses became to the according to soil units and compared with their later knowledge increased theme as of soils and characteristics: for example, poor crop yields supply of farms the materials and machinery to may be correlated with mottled subsoils caused Now, it is widened the scope of management. by impeded drainage; good pasture growth with possible adapt most soils most theoretically to to high phosphorus content or with deep topsoils; uses, but frequently cost of altering proper- the the and uneven tree growth with compact subsoil or is proportion ties of the soils out of to the with severe erosion. Some examples of general yield products. For food of the example, crops correlations of soils and land use are given in may be grown on coral atolls or antarctic sands, sections 1 to 4 of Chapter 4. From comparisons but, except in an emergency, food is brought the such as these, soil units are arranged in order of from places where less alteration of soil properties their response to a particular use and manage- is For practical purposes, required. therefore, a ment. Soils with distinct correlations of soil classification should show degrees of difficulty the properties with a land use are selected to separate in for land difficulties changing the soils use. The different levels of suitability. For example, soils encountered for with one use are not the same with a comparable high level of wheat or pasture is another, and there no satisfactory scheme of production per acre under a recommended manage- classification for all potential uses. However, the ment are grouped at one level and those with a immediate purpose is by considering achieved distinctly lower production per acre under similar do each use separately, and to this without re- management at another level. Before deciding on quiring a new survey for each use classification the the different groups the causal factor for lower is made in stages. two production is selected and included in the defini- In first into the stage the soils are classified tion of the class. The definition of the classes series, sets, or other mapping units according types, varies with the degree of detail available for soil characteristics of whole soil as determined to the properties and of the experience. by soil surveys and associated chemical, physical, Untried soils are interpolated according to the and biological analyses. As described in Chapter 1, degree to which they possess the desirable (or these characteristics are derived from the interac- undesirable) properties. For these comparisons tion of natural factors such as climate and vegeta- and interpolations the soil units should be ar- tion on parent materials. Land use brings into the ranged in sequences according to parent material, soil system the effects of man and his activities- drainage, stage of mineral weathering or rate of cultivation, irrigation, drainage, topdressing, and decomposition This the sowing and harvesting of particular plants. of organic matter. arrange- for These human activities have a different basis and ment also shows up the soils which more pattern yield greatest benefit from the natural factors, and generally investigation would the to

124 5-2 the classification. Where staff and finance are allows flexibility in the demands of different plants limited, it is very important to know on which on soil properties, so a soil such as Tarawera soils or on which problems to concentrate research. gravel may be Class 3 for growing tomatoes, In the two-phase method of soil assessment new Class 2 for growing pasture, and Class 1 for information on management can be added without softwood timber. It can embrace assessments of the need for new surveys. For example, the re- soils for engineering use where the concern is classification required by the discovery of the stability under physical pressure. Provided the benefits from small additions of molybdenum to establishment of the soil units is done before the pastures on some soils was made by transferring inclusion of soil-management data, one basic soil these soils to a higher class. The method also map can serve many purposes.

5*2* PURPOSES OF CLASSIFICATION

Classifications of New Zealand soils have been can be more precise and classes may be arranged made for various purposes. Some examples are: according to degrees of suitability for a particular Classes of soils for fruit growing on Here- plant, or to numerical assessments of productivity. taunga Plains (Atkinson, 1939), in Alexandra No matter what basis, however, the soil classes district (McCraw, 1964), or for cropping on are not direct recommendations for a particular Gisborne Plains (Renouf, 1962); land use. Such recommendations require the Classes of soils for cropping and pastoral use inclusion of geographic factors such as the loca- in mid Hawke’s Bay (Pohlen et al., 1947), part tion of the soil in relation to towns or roads, and of Geraldine County (Raeside, et al., 1959), in of economic factors such as costs of fertilisers or Southland (Cutler, 1961), and in Western marketing returns; these factors are beyond the Samoa (Wright, 1963); scope of soil work and have to be assessed separ- Classes of soils for pastoral uses in the Mana- ately. Also to be noted is that the classifications watu sand country (Cowie et al., 1958), in are of soil, not of land, which is a wider term in- Matakaoa County (Gibbs, 1954), in Bay of volving the pattern of soils in relation to economic Plenty (Town and Country Planning Branch, and other non-soil factors such as size and tenure 1962), in Akitio County (Woods, 1951), Marl- of farms or availability of water and power. borough (Gibbs and Vucetich, 1962), and Nevertheless soil classifications are needed, with Northland (Town and Country Planning Branch, other information, for preparing classifications of 1964). land as for example in town and country planning Classes of soil for pastoral or forestry uses (Town and Country Planning Branch, 1959 and in Kaitangata district (Wright et al., 1951), and 1962), in land-capability classification (Greenall in Chatham Islands (Wright, 1959). and Hamilton, 1954; Dunbar, 1963), and in general The definition of the classes depends mainly land classification (Taylor et al., 1959; Cumber- on the degree of soil detail and amount of ex- land, 1944). Methods and experience with classifica- perience available. Classes defined according to tion in other countries are described by Jacks degrees of soil limitation to plant growth are (1946) and in a series of papers on soil classifica- well suited to the level of information obtained by tion, soil fertility and land use published in 1963 surveys on scales of 1 to 4 miles to 1 inch. For areas in the Transactions of the Joint Meeting of Com- with detailed soil maps supported by measure- missions IV and V of the International Society of ments of plant growth on soil types, the conclusions Soil Science (1962).

5-3- CLASSIFICATION FOR PASTORAL FARMING

Most New Zealand soils are used for grassland tions are slight, in Classes 2 and 5 they are moder- farming, and when classified by a scheme of ate, and in Classes 3 and 6, severe. Descriptions of limitations (modified from Grange, 1944) they these classes are given in Table 5-3-1 with sub- illustrate the value of soil classification for land divisions detailing the chief soil limitations to use. In this scheme soils are grouped into six main pastoral production. Soil types representative of classes. Classes 1, 2, and 3 comprise soils on flat each subclass are listed by their geographic names. lands, distribution 1 and rolling and Classes 4, 5, and 6, soils on The of the classes on : 1,000,000 hilly and steep lands. The division on land slopes Soil Maps of North and South Islands is shown is made to allow for major differences of moisture on maps 3 and 4 (in pocket at end of bulletin), conditions and of grassland management on and within the size limitations of these maps the rolling and hilly slopes. In Classes 1 and 4 limita- pattern demonstrates broad contrasts and simi-

125 5-3

TABLE 5-3*1* Classification of Soils for Potential Pastoral Use.

(Geographic names of representative soil types for each subclass in the North and South Islands are listed in brackets.)

CLASS 1. Soils of flat and rolling lands with slight soil limitations to pastoral use. IA limitations of nutrients (Manawatu, Rotomahana, Rangitoto, Paengaroa, Oropi, Atua, Waihou, Te Kaha, Katikati, Tirau, Ohaupo, Otorohanga, Dunmore, Mapiu, Egmont, New Plymouth, Stratford, Karaka, Levin, Kiwitea, Dannevirke, Patu- mahoe, Naike, Onewhero, Hamilton, Onepoto. Waimakariri, Hokitika, Waimea, Mataura, Tuatapere, Ikamatua, Templeton, Barrhill, Waikakahi, Ahaura, Drummond, Aparima, Waikiwi, Edendale, Mahinapua.) IB limitations of drainage and nutrients (Kairanga, Matapiro, Ohakea, Tokomaru, Marton, Whananaki, Pukepuke, Whatawhata, Kaipara, Waitoa, Hauraki, Glenn, Makerua. Timaru, Opuha, Claremont, Sedgemere, Waitohi, Cheviot, Warepa, Waikoikoi, Crookston, Pukemutu, Wakanui, Taitapu, Kaiapoi, Temuka, Makarewa, Harihari.)

CLAss 2. Soils of flat and rolling lands with moderate soil limitations to pastoral use. 2A limitations of insufficient moisture and to a lesser extent nutrients (Esk, Mangatarata, Ohinepanea, Manawahe, Awakeri, Patea, Foxton, Pinaki, Tinui, Takapau. Lismore, Linnburn, Cluden, Struan, Eyre, Ngapara, Waiareka, Mapua, Motukarara, Hororata, Ruapuna.) 2B limitations of texture, structure or elevation (Kaharoa, Taupo, Ngaroma, Matawai, Aponga, Marua, Okaka, Warkworth, Mata, Waikare, Wharekohe, Ohakune, Warea, Inglewood, Matakaoa, Mairoa, Rangiuru, Waiotu, Awatuna, Rahotu, Pongakawa, Piako, One Tree Point. Cass, Tekapo, Wehenga, Te Anau, Waiuta, Pukaki, Tasman.)

CLASS 3. Soils of flat and rolling lands with severe soil limitations to pastoral use. 3A limitations of nutrients through high fixation or salinity (Okaihau, Ahuriri. Cascade, Manorburn.) 3B limitations of subsoil pans and drainage (Hukerenui, Te Kopuru, Tinopai. Okarito, Onahau.) 3C limitations of excessive moisture, shrinkage (Rukuhia, Mercer. Otanomomo, Kini.) 3D limitations of elevation with cool wet climate (Kaingaroa, Mamaku, Patua, Burrell, Ngauruhoe. Mangatua, Tautuku, Dunton, Kaherekoau.) 3E limitations of frequent dryness (Tarawera, Tukituki. Conroy, Lowburn, Mackenzie, Cromwell, Kairaki, Taumutu, Acheron.)

CLASS 4. Soils of hilly and steep lands with slight to moderate soil limitations to pastoral use. Limitations of nutrients (hill soils Kourarau, Waimarama, Atua, Whetukura, Wairama, Marokopa, Puhoi, Taumata, Waiotira, Konoti,

- Korokoro, Belmont, Matamau, Te Kuiti, Awapuku, Papakauri, Arapohue; steepland soils Turakina, Mahoenui, Pahiatua, Makara, Potikirua. - hill soils Kakahu, Highcliff, Brooklyn, Kaiwera, Owaka, Karitane; - steepland soils Hurunui, Heslington, Kaitoa.

- CLASs 5. Soils of hilly and steep lands with moderate to severe soil limitations to pastoral use. SA limitations of insufficient or excessive moisture (hill soils -Crownthorpe, Paremata, Whangaripo, Marua, Okaka, Churchill, Gwavas, Mangatahi, Red Hill. hill soils - Kauru, Clydevale, Hundalee, Spooner, Arahura, Blackstone, Camphill; steepland soils - Haldon, Waihopai, Omarama, Arrow.) 5B limitation of erosion (hill soils -Paengaroa, Oropi, Taupo, Waitekauri, Raumai, Wanstead, Tinui, Kumeroa, Rangiora, Waitakere; steepland soils -Wangaehu, Taihape, Waitaha, Mangamahu, Whareama. hill soils Teviot, Cass, Tutaki;

- steepland soils Whangamoa, Fairlight, Kekerengu, Pikikiruna, Middlehurst.) - CLASS 6. Soils of hilly and steep lands with severe to very severe soil limitation to pastoral use. Until methods of controlling the accelerated erosion are known the rapidly erodible soils are unsuitable for pastoral use. 6A limitations of nutrients and erosion (hill soils Taita, Maramarua, Pokapu, Tangitiki, Wharerata;

- steepland soils Te Ranga, Mataikona, Tangatara, Pihanga.

- hill soils Lillburn, Denniston, Dunton, Dun, Carrick.)

- 6B limitations of rapid soil erosion (steepland soils Moumahaki, Mokau, Pohangina, Ruatoria, Rimutaka, Ruahine, Urewera, Aroha.

- steepland soils Alexandra, Kaikoura, Dunstan, Opouri, Tekoa, Bealey, Haast, Lewis, Spenser, Otira, Matiri,

- Glenhope, Haupiri, Kaniere, Takitimu, Windley, Eglinton, McKerrow, Resolution.)

126 5-4 larities in potential pastoral usage between different erosion is possible because they are farmed with districts. North Auckland is outstanding for the considerable adjacent areas of Class 1 or 2 soils. diversity and frequent changes of limitations, and Gisborne, Wairarapa, and Wellington districts contrasts with the adjoining South Auckland have extensive areas of high-class hill and steep district where there are extensive and contiguous country (green) with smaller areas of lower-class areas of first-class soils for pastoral use (coloured soils. In the South Island, high-class hill and yellow), with soils of lower class as small enclosures steep country is restricted to small areas mainly or as flanking ridges. The patterns in West Tara- in Canterbury and eastern Otago foothills, whereas naki, Manawatu, Hawke’s Bay, south Canterbury, elsewhere-in Nelson, Marlborough, north Canter- and Southland are similar to that in south Auck- bury, and uplands of Otago-the lower-class hill land. The pumice plateaus of the central North country (blue) predominates. Canterbury has a Island and the inland basins of the central South considerable total area of first-class soils for Island are dominated by the limitations of elevation pastoral use, but the individual areas are separated and moisture. Both islands have large areas of by large strips of second class shallow soils on Class 6 soils (purple; mapped on Coromandel which the regional shortage of moisture is very Peninsula, eastern Taranaki, and the main moun- marked. On the other side of the Southern Alps, tain ranges from East Cape to Fiordland), whose in Westland, excessive moisture is the dominant susceptibility to rapid destruction by erosion factor and results in strong contrasts between under the known methods of extensive grazing young soils on river flats (yellow) and older soils makes them unsuitable for pastoral farming. on terraces (red) and hills (blue and purple). Narrow strips of Class 5 soils (blue) shown along Thus the maps give an overall picture of potential the edges of some of these steepland soils repre- pastoral uses of districts, both within themselves sent areas where grazing without accelerated and in relation to the remainder of New Zealand.

5-4- SOL LIMITATIONS FOR PASTORAL FARMING

Areas of the different subclasses estimated from 3. Nutrient limitations of greater or lesser general surveys are listed in Table 5-5-1. They degree apply on practically all usable soils. show that The widespread application of results gained from past fertiliser give large 1. More than two-thirds of New Zealand experiments will increases production, but is for (69%) is hilly and steep land on which cultiva- of there need further investigation: tion and other practices requiring wheeled proportions machinery are not applicable at the present time. (a) To increase the of useful The development of aerial techniques has re- constituents in commercial fertilisers especially duced the effects of this limitation considerably, for application to steep lands or in distant but further investigation is needed to improve regions from distributing centres, the evenness of distribution and the forms of (b) To find the upper limits of response to aerial fertilisers for steepland soils. Most pastures fertilisers on representative soils. The effects and grazing animals have been selected and bred of these treatments on other elements and for easy sloping land and they need to be the management practices required to main- adapted to meet the requirements of hilly and tain a high level of stocking should be ex- steep lands. amined at the same time. 2. Instability is a severe limitation to the pastoral (c) To study the restrictions of biological use of 26,000,000 acres (40% of New Zealand). and physical conditions on the full utilisation fertilisers. decomposition Pastoral use of these soils increases the danger of The continual of its into of erosion (see Chapter 4) that is harmful both organic matter, incorporation the for loss of soil from one site and for increasing soil system, and the formation of granular deposition and flooding on others. The develop- aggregates by micro-organisms are equally as ment of satisfactory methods for controlling important to high fertility as an adequate biological erosion under pastoral use on any of the soil supply of mineral nutrients. Yet the physical processes types in Classes 5B, 6A or 6B would give con- and are largely uncon- siderable increases in production, but until trolled, and in many soils they need the such methods are established only forestry or assistance comparable with that supplied to reserve uses should be permitted. The main nutrients by fertilisers. In some soils the problem is how to maintain a carpet of grass assistance may be combined with the action under uneven grazing on soils of uneven fertility of the fertilisers, in others separate treatment be subject to strong stresses from gravity. may required.

127 TABLE 5-5-1- Areas of Soil Classes for Pastoral Use and Estimates of Potential Carrying Capacity of New Zealand Soils

Maximum Gross Maximum Gross Total Area for Area for Total Area for Area for n a n ral Use Past al Use Use Past a) Use s Non-p3to)ral Non-pNt Clts1 )a e e

A. North Island B. South Island

lA 3,408,000 C 108,000 3,300,000 9 29,700,000 IA 2,088,000 C 188,000 1,900,000 8 15,200,000 IB 2,239,000 C 109,000 2,130,000 8 17,040,000 IB 2,480,000 C 180,000 2,300,000 5 11,500,000 825,000 6} 5,363,000

827,000 C 12,000 815,000 6 4,890,000 2A 2,825,000 2A 00 3 6,000,000

, ( non-irrigated 2B 2,682,000 F 182,000 2,500,000 6 15,000,000 2B 2,055,000 R 55,000 2,000,000 3 6,000,000 97,000 4 388,000 3A 22,000 R 22,000 3A 97,000 - - 3B 390,000 390,000 4 1,560,000 3B 494,000 F 300,000 194,000 1 194,000 - 172,000 3C 219,000 C 59,000 260,000 4 1,040,000 3C 172,000 C+R - 3D 570,000 F 500,000 70,000 4 280,000 3D 178,000 F+R 178,000 - 3E 157,000 F 100,000 57,000 1 57,000 3E 358,000 358,000 1 358,000

69,955,000 44,605,000

18,800,000 4 2,084,000 2,084,000 31 7,294,000 4 3,760,000 - 3,760,000 5 - SA 1,872,000 F 212,000 1,660,000 4 6,640,000 5A 2,980,000 F 580,000 2,400,000 2} 6,000,000 5B 2,823,000 F 323,000 2,500,000 2} 6,250,000 5B 3,256,000 F 1,256,000 2,000,000 li 3,000,000 6A 822,000 F 422,000 400,000 li 600,000 6A 1,035,000 F 535,000 500,000 1 500,000

6B 7,066,000 R 7,000,000 66,000 1 66,000 6B 13,610,000 R 13,110,000 500,000 1 500,000

17,294,000 26,932,000 32,356,000 33,637,000

2,252,000 for ice 335,000 for alpine rock, scree, and ice alpine rock, scree, and

beds bare 686,000 for lakes, bare sand, etc. 1,198,000 for lakes, river and sand

South 27,953,000 acres Area of counties of North Island 37,087,000 Area of counties of Island =

Classes C cropping F forest R reserves = = = less *Ewe equivalent (e.e.) IA 3E North Island 69,955,000 5% wastage 66,000,000 ewe equivalents -

Agriculture South Island 44,605,000 5% 42,000,000 Conversion according to the Economic Section, Department of (1964). ,, ,, ,, ,,

4 6B North Island 32,356,000 10% 29,000,000 Wether or ewe hogget (0.5 e.e.); other sheep (1 e.e.). - ,, ,, ,, ,,

South Island 17,294,000 10% 15,000,000 Heifer or steer up to I year (4 e.e.); heifer or steer up to 2 years (5 e.e.); ,, ,, ,, ,, dry cow, steer up to 3 years, bullock or bull (6 e.e.); heifer up to 3 years

1963 Potential Pastoral Capacity of Soils 152,000,000 or breeding cow (7 e.e.). ,, ,, 5-5

4. Moisture extremes are widespread limita- to find the potential level of pastoral production its in tions. Moisture deficiency is a limitation on and economic return comparison with 10,000,000 acres of subxerous and subhydrous timber production. soils (15% of New Zealand). As most of this The effects of seasonal soil temperatures in land is rolling and hilly, only a small part of limiting the accumulation of humus and de- granular in this deficiency can be overcome in practice by velopment of structures many probably be irrigation. Amelioration of the remainder re- topsoils of North Auckland could present pasture quires either more efficient absorption of the relieved by modification to the present rainfall by pasture management and management or composition. granular by development of a fine structure, or This classification singles out soil properties pasture adaptation of composition and stock that either need to be accepted or need to be deficiency (dryland farming). management to the changed for pastoral use. With those that are is limitation Moisture excess a severe to many accepted, the aim of investigation should be to in hydrous soils. Excessive water the subsoil find plants and animals that are best suited to the can be removed by suitable drains from all particular slope, moisture, or temperature. The gley podzols. Great hydrous soils except the combination of ryegrass, white clover, and Jersey care must be taken with organic soils to avoid cows or Romney sheep that gives high production But in overdrainage. excessive water the topsoil on the deep soils of moist lowlands needs to be (and its puddling) is limita- consequences of a modified for other soils such as those of steep practically tion to high-density stocking on all lands with their frequent wide ranges of moisture. layer- soils containing more than 10% of If properties are to be changed, it is important to (Edmond, silicate clays when they are wet remember that soils are complex systems and that prob- 1963). This limitation is already a serious changes have multiple effects. Hence drainage, parts Wairarapa lem in of the Manawatu, and cultivation, adding fertilisers, and other soil Otago districts, silty extensive where soils are treatments must be examined for their collateral free draining and few farms have areas of soils effects, and, if necessary, modified or supplemented graze in periods. on which to their stock wet to get maximum plant growth. Maximum produc- fertiliser pasture growth As treatments and tion is the result of balancing many factors. Within increased, puddling become physical proper- are surface will the soils, chemical, and biological plant more and more restrictive on rates of stocking ties must be equally favourable for the increasing loading unless methods of the capacity growth. Outside the soils, plant and stock manage- discovered. of fine-textured soils are ment and the economic and social conditions must growing 5. Seasonally low soil temperatures affect be integrated for and distributing the products Each links 6,000,000 acres of potential grassland. This area of the soils efficiently. of the but in production from system may be lessened by the use of fertilisers the chain of soil to the for full further investigations of fertilisers, pasture mix- consumers must be equally strong the tures, and grassland management is required utilisation of the soil resources.

5*5- POTENTIAL PASTORAL CAPACITY

likely be The classification also provides a means of application of existing information to farms. estimating the potential pastoral capacity of New achieved on most They are maxima ac- but be Zealand soils. For this purpose additional informa- cording to known soil limitations could by discoveries tion was obtained from reports on the maximum increased new or new techniques potentials in annual grazing capacity of numerous soils supplied in the same way as were raised recent years deficiency by farmers, stock firms, and farm advisory officers, by the discovery of molybdenum The and from experimental trials of the Departments and the introduction of aerial topdressing. potentials be by of Agriculture and of Scientific and Industrial may also raised successful results plant Research. From these reports and from interpola- of and animal research. pastoral From potential carrying tions based on soil surveys, the maximum the assessment of the different from capacity of the soils in each subclass was assessed capacity of soil classes and the for permanent grazing, in terms of ewe equivalents per acre. These figures areas of each class available pastoral lands New (Table 5-5-1, column 5) assume full application the total capacity of rural of 120,000,000 of present knowledge of plant and animal to soil Zealand is assessed as equivalent to (generalised types and are considered to represent a realistic ewe equivalents to the nearest million). plot for: compromise between the best results of trials This total makes allowance lands year; on experimental stations and the highest level of (1) 650,000 acres of cropping each

129

I (2) 4,500,000 acres of commercial forestry land; similar findings-differing soil adaptabilities, con- (3) 21,000,000 acres for protection forestry, siderable scope for potential increases in pro- water reserves, and national parks; (4) occupa- ductivity, and the need for continued intensive by farm buildings, tion of soils country roads, investigation into the factors that limit production. belts land (briefly shelter and waste termed All of the classifications show that the maintenance wastage). of high levels of production depends primarily Both (1) (2) and are reservations for the future, upon man’s close collaboration with the soil. purposes and until all the land is needed for these Man must strive to know as much as possible be for grazing. properties the surplus can used about the of the soils to be used so qualifications, Notwithstanding the above the that he can assess the requirements and the results estimated total capacity of 152,000,000 ewe equiva- of alternative uses more accurately. With this lents indicates the general limits of our present information he can select the most efficient use knowledge pastoral of soils for use. With the 1963 for the soil. Efficient selection of soil use is im- population stock at 80,000,000 ewe equivalents, portant today but it must become more so to potential the increase in the future is approximately meet the needs of increasing populations. Whilst o/o. 85 Under the pressure of expanding require- the existing information is sufficient for an im- population ments of export trade and of this mediate large increase in production, there is a increase to 152,000,000 ewes is expected to take continued need for intensive investigation of soil place in 20 years, generation. properties the next to 25 or one and for their application not only to Considering the time required to obtain results agricultural production but also to the housing, from research, there is therefore an urgent need industrial, recreational, and other community uses plants, for studies on soils, and animals to provide for soil. Steady progress in these complementary the data that will keep the capacity target moving aspects of soil science will lead to full conserva- ahead of the increasing demands. tion of soil-that is, maximum permanent use Classifications for non-pastoral uses result in of soil for national benefit.

5’ 6* REFERENCES

ATKINSON, VII. J. D. 1939: Fruitgrowing. In Land Utilisa- McCRAw, J. D. 1964: Soils of Alexandra District. N.Z. tion Report of the Heretaunga Plains. N.Z. Dep. sci. Soil Bur. Bull. 24. 91 pp. industr. Res. Bull. 70. POHLEN, I. J.; HARRIs, C. S.; GIsas, H. S.; RAESIDE, J. D. COWIE, J. D.; SMITH, B. A. J. 1958: Soils and Agriculture 1947: Soils and Some Related Agricultural Aspects of Oroua Downs, Taikorea Oroua of and Glen Districts, Mid Hawke’s Bay. N.Z. Dep. sci. industr. Res. Bull. 94. Manawatu County. N.Z. Soil Bur. Bull. 16. 56 pp. 176 pp.

CUMBERLAND, K. B. 1944: The Survey and Classification RAESIDE, J. D.; CAMERON, M.; MILLER, R. B. 1959: Soils of Land in New Zealand: A Basis for Planning. Trans. and Agriculture of Part Geraldine County, N.Z. Soil N.Z. roy. Soc. 74: 185-95. Bur. Bull. 13. 65 pp. CUTLER, E. J. B. 1961: The Soils of Southland and Their RENOUF, L. R. 1962: Soils and Crops for Processing. In Potential Uses. Proc. N.Z. Grassl. Ass. 23: 15-26. Soils and Agriculture of Gisborne Plains. N.Z. Soil Bur. Bull. 20. DUNBAR, G. 1963: Land Use Capability Patterns in Canter- bury. In ’Soil Conservation and the Planning of Land TAYLOR, N. H.; POHLEN, 1. J. 1962: Soil Survey Method. Use’. 10th N.Z. Science Congress, Christchurch. N.Z. Soil Bur. Bull. 25. 242 pp.

EDMOND, D. B. 1963: Effects of Treading Perennial Rye- TAYLOR, N. H.; POHLEN, I. J.; Scorr, R. H.; McKINNoN, grass and White Clover Pastures in Winter and Summer at A. D. 1959: Soils and Land Use. Pp. 28-33 and Maps 12 Two Moisture Levels. N.Z. J. agric. Res. 6: 265-76. and 13 in a ’A Descriptive Atlas of New Zealand’, edited by A. H. McLintock. Govt. Printer, Wellington. Gises, H. S. 1954: Soils and Agriculture of Matakaoa County, New Zealand. N.Z. Soil Bur. Bull. 11. 52 pp. TOWN COUNTRY PLANNING BRANCH, AND MINISTRY OF 1966: The Soil Factor in the Assessment of Land WORKs, N.Z. 1959: ’West Coast Region. National Re- - Resources. N.Z. agric. Sci. 1(6): 11-14. sources Survey Part 1.’ Govt. Printer, Wellington. Re National Resources GInss, H. S.; VUCETICH, C. G. 1962: Soils of Marlborough. e P 2 G Proc. N.Z. Grassl. Ass. 24: 8-17. t tPlent 1964: ’Northland Region. National Resources Sur------GRANGE, L. I. 1944: A Basic Scheme for Land Classifica- vey Part 2.’ Govt. Printer, Wellington, tion. N.Z. J. Sci. A26: 136-41. WOODS, L. 1951: Developing Marginal Lands. N.Z. Dep. GREENALL, A. F.; HAMILTON, D. 1954: Soil Conservation Agric. Bull. 339. 123 pp. Surveys in New Zealand. N.Z. J. Sci. Tech. A35: 505-17. WRIGar, A. C. S. 1959: Soils of Chatham Island (Rekohu). JACKS, G. V. 1946: Land Classification. Tech. Comm. imp. N.Z. Soil Bur. Bull. 19. 60 pp. Bur. Soil Sci. 43. 90 pp. ------1963: Soils and Land Use of Western Samoa. N.Z. Soil Bur. Bull. 22. 191 pp. LEAMY, M. L. [1963]: The Correlation of Soil Classification and Soil Capability of the Upper Clutha Valley, Otago, WRIGHT, A. C. S.; RICHARDs, J.; Loss, W. R.; MILLER, New Zealand. Trans. Jt Meet. Comm. IV and V, int. R. B. 1951: Soils and Their Utilisation, Green Island

- Soc. Soil Sci. (1962), pp. 749-54. Kaitangata District. N.Z. Soil Bur. Bull. 6. 36 pp.

130 GLOSSARY OF PLANT NAMES USED IN THE TEXT

akeake Dodonaea viscosa Lupin (tree) Lupinus arboreus annual poa Poa annua lycopodium Lycopodium spp. ash Fraxinus excelsior mahoe Melicytus ramillorus barley grass Hordeum spp. mamaku Cyathea medullaris Nothofagus beech, spp. manuka Leptospermum scoparium and L. black N. solandri var. solandri ericoides hard N. truncata marram grass Ammophila arenaria N. var. mountain solandri cliffortioides matagouri Discaria toumatou red N. Jusca matai, black pine Podocarpus spicatus silver N. menziesii meadow grass Poa trivialis blackberry Rubus fruticosus agg. mingimingi Cyathodes spp. (Leucopogon) blue tussock Poa colensoi miro Podocarpus ferrugineus bracken fern Pteridium aquilinum var. esculentum mountain daisy Celmisia spp. brome Bromus tectorum br oak Quercus robur tm,duced Sarothamnus scoparius Carmichaelia spp. native paspalum Paspalum dilatatum chord broom Chordospartium stevensonii patotara Cyathodes fraseri browntop Agrostis tenuis pine, Pinus spp. Corsican P. nigra Cordyline australis cabbage tree Lodgepole P. contorta Hypochoeris spp. catsear Maritime P. pinaster clover, radiata P. radiata clustered Trifolium glomeratum Scots P. silvestris red T. pratense western yellow P. ponderosa T. striatum striated poplar Populus spp. T. subterraneum subterranean puriri Vitex lucens suckling T. dubium white T. repens cocksfoot Dactylis glomerata rata, Metrosideros robusta common orache Atriplex patula northern M. coprosma Coprosma spp. southern umbellata Sporobolus crested dogstail Cynosurus cristatus ratstail capensis raupo Typha muelleri Chionochloa dandelion Taraxacum oficiale red tussock rubra pine danthonia Notodanthonia spp. rimu, red Dacrydium cupressinum Lolium perenne douglas fir Pseudotsuga taxifolia tyegrass Dracophyllum Dracophyllum spp. scabweed Raoulia spp. silver pine Dacrydium colensoi Poa fescue tussock Festuca novae-zelandiae silver tussock caespitosa snowgrass Chionochloa spp. flax (New Zealand) Phormium tenax fuchsia Fuchsia excorticata sorrel Rumex acetosella agg. sweet vernal Anthoxanthum odoratum gorse Ulex europaeus tauhinu Cassinia spp. hair grass Vulpia dertonensis tall tussock Chionochloa spp. hakea Hakea acicularis taraire Beilschmiedia tarairi hard tussock Festuca novae-zelandiae tawa Beilschmiedia tawa hare’s-foot trefoil Trifolium arvense thistle Cirsium spp. heath Erica lusitanica totara Podocarpus totara twitch Agropyron repens kahikatea, white Pod dacrydioides ca u umbrella fern Gleichenia circinata kapnmhi karaka Corynocarpus laevigatus Thuja plicata kauri Agathis australis western red cedar willow, Salix spp. Kentucky blue- crack S. fragilis Poa pratensis grass S. babylonica kohekohe Dysoxylum spectabile weeping wire rush Hypolaena laterifolia wiwi rush Schoenus spp. larch Larix decidua Large birdsfoot- yarrow Achillea millefolium trefoil Lotus pedunculatus (L. uliginosus) lucerne Medicago sativa Yorkshire fog Holcus lanatus

131 GENERAL INDEX

(Numbers in bold type refer to definitions of soil terms; n refers to footnotes in text.)

A yellow-brown earths, 55, 58-9, 61-2, 70, 73-4, 91, 92, Accelerated erosion, see Erosion 115-6; Pl. 9, 10, 21, 22, 25, 26 Accumulation, 26-7 yellow-brown loams, 51-2, 53, 60-1; Pl. 23,27 Ad-, 22 yellow-brown sands, 56, 74 Age of soil, 14 yellow-grey earths, 54-5, 57-8, 68-70; Pl. 21, 23, 25, Alluvium, 9-10 27 Alpine barrens, 13 Chronosequences, 105 Altitudinal zones, 22-3; fig. 2*3-2 Classification alpine, subalpine, 22 land use, 124-30 Alvic soils, 23 soil, see Soil classification Amadic soils, 23 Clays, 23 n Amo-, 23 amorphous, 23 Argillisation, 23 classification, 45 conformable, 24 crystalline layer silicates, 23 grade (sub-, sur-, supra-,), 23-5; fig. 2-3-3 crystalline oxides, 23 indices, 25 illuviation, 27-8 kinds, 23 Climate, 10-11, 33-44 potential rate, 25 classification, 33, 35; tab. 2-7-2-2-7-5 Ash beds (volcanic), distribution, 9; fig. 1-2-1 soil-forming factor, 15 soil-forming, 9 zones, see Altitudinal, Latitudinal Azonal soils, 30, 89; tab. 2-5-1 Clinic soils, 26 land use, 95-6 Clover growth, see White clover growth Co-, 23; tab. 2-5-1

D B De-, 22 Basal form, 20-1 Dental caries and soils, 112 Base saturation, 28 Drift deposits, 8-10 factor Biotic factor, see Living organisms, soil-forming alluvium, loess, sand, soliflual deposits, volcanic ash, Bioturbic soils, 27 9-10. Brown granular clays and loams Drift regime, 19-20, 26 erosion, 117 land use, 94, 95 n E see Central, Northern, Southern zone soils E-, 22 Brown-grey earths, 21, 76; Pl. 21, 25 Earthworm(s), change in populations, 107 erosion, 113-4 Eastern region, South Island, 79-83; fig. 3-1*3 land use, 89 Ecology, 105 Brown loams, 94 n; Pl. 23, 27 Egg-cup podzols, 64 Burrell ash, 9, 53 Egmont ash, 9, 53 Bush sickness, 93 El-, elad-, elde-, ele-, 22 Element mobility, tab. 2-2-1 Energy 20 C status, main energy status, 22-3 Categories of classification, 20-9 solar energy, fig. 2*3-1 I-basal form, 20-1 Enleaching, 28 II-(main) energy status, 22-3 Erosion phases, 22 n community and, 118 III-(a) argillisation, 23-6 normal erosion, 112 (b) accumulation, removal, mixing, 26-7 soil (accelerated) erosion, 19, 112-8 IV-horizon development, 27-8 by soil groups, 113-8 V---enleaching, 28 F VI-parent material, 28 VII-surface or subsoil horizons, 28-9 Farming, soil changes caused by, 104-9 Central region, South Island, 75-9; fig. 3-1-3 Fern lands, 13 Central zone, 22, 47 Fertility, transference, 17 soils: Fire, effects, 112-9 brown granular loams, 61, 71; Pl. 23, 27 Flushing, soil process, 19 gley recent soils, 56-7, 59-60 Forest, 96-9 gley soils, 62, 71-2 classes, 12 organic soils, 56-7, 62-3, 71-2, 74 exotic, 96-9 podzols, 70-1, 73 native, 96-8 recent soils, 56-7, 59-60, 62, 71-2, 74 pre-European, 12 from volcanic ash, 48, 50, 53; PI. 24, 28 protection, 97-8 rendzinas, 71 Forestry, 96--9 saline gley soils, 59-60 Forms, soil, 20-1 saline soils, 71-2 Fragipan, 21, 28 steepland soils, 74--5 Fulviform soils, 21, 23

133 G Mid-brown loams, 94 Milk, composition, 110; 4-5-1, 4-5-2 Gammate structure, 21, 28 tab. Mixing, 18, 19, 26--7, 28 net gammate, subgammate, 28 mechanical, Moder, 29 n Genetic analysis, tab. 2-4-1 Moisture, climate class, tab. 2-7-2-2-7-5 names, 29-30; tab. 2-4-1 effective, 22 soil classification, 20-9 figs. derivation of 29 index, 34; 2-7 2-2-7-7; tab. 2*7-2-2*7-4 terms, figz4-1-3 principal soil classes, 20, 23-7 regime, see Soil moisture 20-30; tab. 2-5-1 terminology, n Geology, 7-10 Mor, 29 Moroid profile, 18, 28 Gley podzols, see Southern zone soils organic Mull, 29 n Gley recent soils, see Central, Southern zone soils Mulloid profile, 18, 28 Gley soils, 21 organic erosion, 117 N land use, 94-5, 96 9, see Central, Northern, Southern zone soils Newall ash, 53 Gleying, 28 Ngauruhoe ash, 9, 48-50, 52 Grass-clover association, 105 Nigriform soils, 21 Grasslands, 12 Nomenclature 15; 2-5-1 lowland short tussock, 12 common, tab. 15, 29-30; 2*5-1 lowland tall 12-3 technical, tab. tussock, intergrades, 27 subalpine, 12 of Great Soil Groups, 20 see also Terminology Normal 112 Ground-water podzols, see Northern zone soils erosion, Gumlands, 93 Normal site, 30 North Auckland region, 63-67; fig. 3-1-3 H North-eastern region, South Island, 67-72; fig. 3.1.3 zone, 22, 47 Hamilton ash, 9, 60, 61 Nnthern High country zone, 47 brown granular clays and loams, 65; Pl. 23, 27 yellow-brown 77-8; 22, earths, Pl. 26 gley soils, 67 oslion 1 ground-water podzol, 65; Pl. 22, 26 or)gd i s6 Hydrous, 32 moisture class, 5 Pl. 22, 26 H ss, 32 podzolis llow-brown earths, 64-5; Pl. 22, 26 Tm gn ids ,c rendzina, 63; Pl. 24, 28 yellow-brown earths, 61-2, 64, 92-3, 116; PI. 11, 12, 27 -i-, 22, 26 23 -ic, yellow-brown sands, 66-7 Illimerisation, 17, 18 North Island Illuviation, 27-8 geology, 8 Intergrades, 21, 27 soil surveys, 87 Intrazonal soils, 30, 89; tab, 2-5-1 soils, 48-67 ntd Nutrient requirements, of grass-clover association, 105 Ir o 13 1 O K

Kaharoa ash, 9, 50, 51 -o ,sI body, 24 Ombrogenous peat, 26 L Organic cycle, 17, 105 Landforms, 7-10 Organic regime, 17-19 Land use, 89-123 changes, 106-7 soil classification for, 124-30 effects of erosion, 113 Latiform soils, 21, 23 profile, 28 Latitudinal zones, 22, 23; fig. 2-3-2 Organic soils, 21 tropic, subtropic, temperate, subantarctic, antarctic, 22 erosion, 117 Leaching, 17 land use, 94 rate, 28 see Central, Northern, Southern zone soils related to plant growth, 103-4; tab. 4-3-3 Organiform soils, 21, 26 Lithic soils, 26-7 Organous soils, 26 Lithosols, 26 23 -ous, Living organisms, soil-forming factor, 15 Oxadic soils, 23 Lodic soils, 26 Oxi-, 23 Loess, distribution, 8, 19 Luvic soils, 26, 27 P Pakihi soils, 92 M Palliform soils, 21 Madentiform soils, 21 Parent material, 15, 28 Maihiihi ash, 61 Peats Mairoa ash, 9, 60, 61 blanket, 26 Manawatu-Wellington region, 54-7; fig. 3-1-3 concave basin, 26 Maori agriculture, 11 distribution, 10 settlement, 11 ombrogenous, 26 soils, 11 soligenous, 26 Meadow soils, 93 topogenous, 26 Melanisation, 29 see also Organic soils

134 Pedological peneplain, 18 Soil, 7, 15-6 Pedology, 15 Soil body, 16 Per-, 22 Soil classification, 15-46 Phases, 27 genetic, 20-30 moisture, see Soil moisture phases for land use, 124-30 clay, 45 for pastoral farming, 125-30; tab. 5-3-1; Maps 3 and 4 Planning, Town and Country, 119-23 zonal, 30; tab. 2*5-1 Platic soils, 26 Soil conservation, 112-9, 97-8 Podiform soils, 21 Soil environment, 7-14 Podzols, 21 Soil erosion, see Erosion erosion, 116-7 Soil family, 15 land use, 92, 93 Soil fertility, 20 see Central, Northern, Southern zone soils Soil-forming factors, 15 Podzolisation, process, 18 climate, 10-11 Podzolised yellow-brown earths, 64-5; tab. 2-5-1 living organisms, 15 erosion, 116--7 parent material, 7-10 land use, 92-3 time, 14 see Northern, Southern zone soils topography, 7-10 Potential carrying capacity, 129-30; tab. 5-5-1 Soil group, 15 Potential evapotranspiration, 32, 33; fig. 2-7-2-2-7-7 maps, fig. 3-11, 3-1-2 Pre-argillised parent materials, 24 Soil, induced changes, 104-109 Precipitation, fig. 2-7-2-2-7-7 Soil limitations, for pastoral farming, 127, 129; tab. Pseudomadentiform soils, 21 n 5-3-1 Puddling, see Treading Soil maps, 47 Pumice, 9, 48, 50-2 Soil mapping units, 47 Puniho ash bed, 9 Soil mixing, 18, 19 Soil-moisture classes, 32 Dry: 32 R xerous, subxerous, Moist: subbygrous, hygrous, subhydrous, hydrous, 32 Recent soils Soil-moisture phases, 27, 32 erosion, 117-8 diagrams, fig. 2*7-2-2-7-7 Central, Northern, Southern see zone soils Soil pattern and land use, 89-96 Recent soils from alluvium Soil-plant-animal relationships, 110-2 land use, 95 Soils, polycyclic, 16, 26 see Southern zone soils Soil series, 15 Recent soils from loess, see Southern zone soils Soil suite, 15 from Recent soils volcanic ash Soil system, 15-16 erosion, 118 drift regime, 19-20 land use, 95 organic regime, 17-19 Central see zone soils wasting regime, 16-17 Red and brown loams, 21, 66 Soligenous peats, 26 117 erosion, Solonetzic soils, 19, 21, 76; Pl. 24, 28 land 94; Pl. use, 17, 18 Soloniform soils, 21 Red loams, 94; Pl. 23, 27 South Auckland region, 60-3; fig. 31-3 Regic soils, 26 Southern region, South Island, 83-7; fig. 3*1-3 Regions, 47; fig. 31-3 Southern zone, 47 Regosols, 26 soils: process, Removal, soil 26-7 brown granular clays and loams, 82, 86; Pl. 24, 28 Rendzic 71, 82 soils, gley podzols, 92, 96; Pl. 13, 14, 22, 26 Rendzmas gley soils, 83; PI. 24, 28 erosion, I 17 organic soils, 74, 83, 86-7; Pl. 24, 28 land use, 93 podzols, 70-1, 73, 78-9, 81-2, 85, 92 Central, Northern, Southern see zone soils podzolised yellow-brown earths, 92; PI. 22, 26 Rendzina-like soils, 21 recent soils, 74, 82 Rocks, 7-10 from alluvium, 79, 82, 87; PI. 24, 28 Rotomahana mud, 9, 50, 52 ash, from loess, 83; Pl. 24, 28 Ryegrass growth, relation to rendzinas, 82 site vegetation, 101; 4-3-1 tab. saline gley soils, 83 soil chemistry, 101; 4-3-3 tab. steepland soils, 74-5 soil groups, 103-4; 4-3-2 Pl. 21-24 tab. yellow-brown earths, 73-4, 81-2, 84-5, 91-2, 115-6; soil leaching, 103; 4*3*3 tab. Pl. 9, 10, 22, 26 yellow-brown loams, 86 S yellow-brown sands, 74, 82, 86 84; Pl. 8, 21, 25 Saline soils, 21 yellow-grey earths, 77, 79-80, 7, see Central zone soils South Island Saline gley recent soils, see Central zone soils geology, 8 Saline gley soils, see Central, Southern zone soils soil surveys, 87-8 Scrub lands, 13 soils, 67-87 Sedimentation, 14, 112 Spadiform soils, 21, 23 Shallow stony soils, 81 Steepland soils Sheep 59, 67, 85, 86 tissues, microelements, tab. 4-5-5 distribution and description, 52, 53-4, 55, Sitiform soils, 21 see also Central, Southern zone soils Skeletal soils, 21, 26 erosion, 113-7 Skeliform soils, 21, 23, 26 forestry, 97-8 Skelous soils, 26 land use, 95-6 Slickensided ped, 19 76-8, 79-82; 2-5-1 related to soil groups, 68-71, tab. Sod, moroid and mulloid, 28-9 Stratford ash, 9, 53

135 Structure, induced changes, 107 W Subargillisation, 24 Waihi ash, 9, 51, 52 Subhydrous moisture class, 32 Waimihia ash, 9 Subhygrous moisture class, 32 Waiweranui ash, 9 Subxerous moisture 32 class, Wairarapa-Gisborne region, 57-60; fig. 3-1-3 Supra-argillisation, 25 Wasting regime, 16-7 Surargillisation, 24 Water, Thornthwaite classification, 33--44 Swamp lands, 13 balance, fig. 2-7-2-2*7-7 deficiency, 34; fig. 2-7-2-2-7-7 need, 33, 34 T surplus, 33, 34; fig. 2-7-2-2*7*7 Weathering, 16 Tahurangi ash, 9 chemical, 16 Taita Experimental Station, frontispiece see also Argillisation Taranaki-Wanganui region, 52-4; fig. 3-1-3 physical, 16 Tararewa, lapilli, ash, 9, 50, 52 rate, 28 Taupo 9, 51-2 ash, Western region, South Island, 72-5; fig. 3*1-3 Taupo-Bay Plenty 48, 50-2; fig. 3-1-3 of region, Whakatane ash, 9, 51 Temperature, 10-11 Wind, 10-1 fig. mean annual, 2*3-2 fahn, 11 regime, 22 growth, White clover relation to Terminology: affixes site vegetation, 101; tab. 4-3-1 ad-, af-, amo-, co-, de-, e-, elad-, ele-, elpro-, el-, elde-, soil chemistry, 101; tab. 4-3-3 22, 23; 2-5*1 tab. soil groups, 103-4; tab. 4-3-2; Pl. 25-28 oxi-, per-, pro-, 22, 23 soil leaching, 103; tab. 4-3-3 23, 27 -ic, -oid, -ous, intergrades X 27 -i-, -o-, Xerous, moisture class, 32 derivation, 29 clays Y allo-, ferro-, gibbso-, hydroalumino-, hydrofelso-, Yellow-brown earths, 21 illo-, kao-, mico-, moro-, palago-, silico-, titano-, erosion, 115-7 vermo-, 45 land use, 91-3 Thermal-efficiency, and index, 34; 2-7-2; fig. 2*7-2- tab. see Central (55-74), High country (77-8), 2-7-7 Northern (61, 64), and Southern (73-85) zone soils Th nthwa . Yell loams ssification, 33-44; fig. 2-7-2-2-7-7 -brown moisture (regime) index, 34-44 land use, 94 Time, soil-forming factor, 14 see Central (51-61), and Southern (86) zone soils Tirau ash, 9, 60 Yellow-brown pumice soils, 50-1, 59; Pl. 23, 27 Tongariro ash, 9, 52 erosion, 117 Topogenous peats, 26 forestry, 98 Topography, soil-forming factor, 7-10, 15 land 93-4 Town and Country Planning, 119-123 use, Yellow-brown sands Acts of Parhament, 119, 120, 123 erosion, 117 Heretaunga Plains, 120, 122 land use, 93 Talert Plams, 122 reclamation, 99 Treading, changes caused by, 107 see Central (56, 74), Northern (66-7), and Tussock, see Grasslands Southern (74-86) zone soils Yellow-grey earths, 21 erosion, 114-5 V land use, 89, 91 see Central (54-70), and Southern (77-84) zone soils Vegetation, 11-13 Z pre-European, 12; tab. 1*4-1 present day, 13; I’4-1 tab. Zonal soil classification, 30; tab. 2-5-1 96-9; 1-4-1 changes, tab. soils, 30-89; tab. 2-5-1 Volcanic ash, 8-9 land use, 89-96 Volcanic rocks, 8 related to climate, 35; tab. 2-7-5 Volic soils, 26 Zones, 47

136 SORS INDEX

information for is be found in Soil names in italics are those of reference sites. Further analytical these to Chapter 11, in Part 3 of this bulletin, Soils of New Zealand, N.Z. Soil Bur. Bull 26(3).

Legend symbols are those used on the Soil Maps of the North Island and the South Island, New Zealand (Scale 1:1,000,000), accompanying this volume.

Legend Legend symbol symbol Acheron 24b 77, 78 Eglinton 72a 75, 86 Ahaura 28b 70, 73-4 Egmont 64a 53, 60-1; tab. 4-3-1, 4-5-1, 4-3-1, 4-5-2; Pl. 15, 23, 27 Ahuriri 89a 60, 112; tab. 4-5-3- 4 5 5; Pl. 24, 28 Esk 94a 60 - - Akeake 86a 62 Eyre 91a 83 Alexandra 3a 76, 113; Pl. 5 Aparima 17a 84 Aponga 38b 64 Arahura 28a 70, 73, 74 Foxton 54a,b,c 56,117 Aranga 75a 65 Arapohue 52a 63; tab. 4 3 1; Pl. 24, 28 - - Arrow 6a 77 Ashwick 19b 81 Glendhu 7a 69 Atawhai 70b 71 Grampians 10 76 Atua 20a 58, 114 Gwavas 22a 58 Awapuku 74a, 76a 65

Haast 45a 78, 116 Barrhill 93a 83, 100; 4 3 1; Pl. 24, 28 14b 58 tab. - - Halcombe 54-5, Bealey 26b 78, 116 Haldon 10a 69, 80, 106; tab.4-4*l Becks in la 76 Hamilton 73b 61, 100; tab. 4-3-1; PI. 23, 27 Belmont 33c 55, 101; tab. 4-3-1; Pl. 22, 26 Harihari 92b 74 Blackball in 28a 74 Hauraki 86a 62; tab.4-5-1, 4-5-2 Blackstone 4a 77, 114 Hauroko 28a 85 Brooklyn 70b 71 Heslington 50a 71 Bryneira 72b 86 Highcliff 67b 82 Burrell 96c 53 Hinahina 43a 73, 85 Hokitika 90b 74 Hollyford 72a 86 Horea 55b 62 Camphill 67a 117 Hororata 19a 81 Cargill 68a 82, 117 Horotiu 66c 61 Carnavon 54c 56 Houhora 55a 67 Cass 25a 78, 115; Pl. 6 Hukerenui 47a 65; tab. 4-4-1 Churchill 73c 61 Hundalee 16b 69 Clare la 76 Hurunui 30b 70, 81, 116 Claremont 8a 80 Cluden 4a 77, 100, 101, 114; tab. 4 3 1; - - Pl. 21, 25 Clydevale 11b 80 Ikamatua 90b 74 Conroy la 76, 101, 113; tab. 2-4-1, Inglewood 65b 53 4-3-1; Pl. 22, 25 Cromwell in lb 76 Crookston 16a 80 Crown 13a 58, I 14 Judgeford 32b 55; tab. 4 3 1; PI. 10, 22, 26 thorpe - -

Dairy Flat in 38d 64 Kaharoa 56b,c 50 Dannevirke 33a 59; tab. 4 5 1; PI. 23, 27 Kaherekoau 82a 86-7 - - Denniston 44b 73, 116 Kahui 64b 53 Drummond 68b 86 Kaikoura 26a 78, 115 Drybread 2a 76, 113-4 Kaingaroa 57g 51, 100, 101, 117; tab. 4-3-1; Dublin 24b 77-8 Pl. 23, 27 Dun 71a 71, 117 Kaipaki 84a 62-3 Dunstan 26a 78 Kaipara 86b 67

137 Legend Legend symbol symbol Kairaki 53a 82, I17 Molesworth 24a 77 Kairanga 95a 57, 60 Molyneux lb 76; PI. 5 Kaitangata 16c 80-1 Monowai 59a 86 Kaitoa 51a 71 Motukarara 88a 83 Kakahu in 16c 80-1 Moumahaki 36b 54 Karaka 66b 61 Mackenzie Ic 76 Karangarua 92b 74 McKerrow 46b 75 Karitane 15a 80 Katikati 60a 51 Katrine 25a 78 Kauru 7a 80 Kekerengu 16b 69 Naike 73b 61; tab. 4-3-1; Pl. 23, 27 Kenepuru 30c 70 New Plymouth 65a 53 Kini 81b 74 Ngapara 4b 69, 80, 114 Kiripaka 77a 66; tab. 4 3 1; Pl. 23, 27 Ng aroma 57d 50-1 - - Kiwitea 66a 55 Ngaumu 34a 59 Kopua Ngauruhoe 97a 100, 33a,b 59 48-9, 101; tab. 4-3-1; Pl. Korokoro 32b 55, 115; Pl. 9, 10 24, 28 Kotinga 43c 73 Kourarau 31a 58-9 Kowai 93a 83 Oamaru 67a 82 Ohai 18a 84 Ohakune 63a 52 b er aepanea O b -2 Okaihau 30, 66; Levin 66a 55 79a tab. 2 -4 -1, 4 -3 -1; Pl. 27 a 78 , Okaka 30a,b @23, I um O Pll a t tab. 4 3 1; Pl. snnburn 3d 154; tab. 4 3 1; - - - - 1 2 2601; 21, 25 Longwood 44b 85Pl. Omanaia 38a 64 Lowburn Omarama 2a 76, 101; tab. 4-3-1; Pl. 21, 25 38b Onahau 43c 73 One Tree Point 48b 65, 101; tab. 4 3 1; Pl. 22, 26 - - Onewhero 73a 61 Mahinapua 53b 74 Opaheke 41a 62, 64 Mahoenui 35b 54, 56, 59, 115 Opita 73c 61 Maihiihi 62b 61 Opouri 30c 70 Mairaki Ila 80 Opuha 12a 80 Matroa 62d 61 Oropi 56b 50 Makara 35a 56, 116; Pl. 10 Otanewainuku 58a 52 Makarewa 92a 87 Otanomomo 8 lb 86, 100; tab. 4 3 1; Pl. 24, 28 Makarua 83a 57 - - Otira 45b 74 Makotuku 31b 58 Otorohanga 62a 61 Malakoff 67b 86 Oturehua 5a 77, I 14 Mamaku 57f 51 Owaka 29a 85 Manawatu 94a, 95a 57, 60 Mangamahu 36a 54, 59 Mangatarata 13b 58 Mangatawhiti 41c 62 Mangatea 31c 62 Paengaroa 56a 50 Mangaweka 20b 100; 4 3 1; PI. 22, 26 Pahaoa 35a 59 tab. - - Manorburn inlb 76;tab.4-3-l;PI.24,28 Pahiatua 35b 59,115 Manunui 57d 51 Papakauri 77a 61, 66; tab. 4-3-1; Pl. 23, 27 Mapiu 62c 61 Paremata 21b 55; tab. 4-3-1; Pl. 21, 25 Mapua 18a 69 Patua 65b 53, 61; tab. 4-3-1; Pl. 23, 27 Maraetotara 21a 58 Patumahoe 73a 61 Marakopa 32a 62 Patutu 30a 70 Maramarua 41c 62 Pihanga 98a 52 Marton 14a 54-5, 58, 101; tab. 4 3 1; Pl. Pikikiruna 51b 75 - - 21, 25 Pinaki 54a 66-7 Marua 39d, 40a 64, 106, 116; tab. 4-4-1 Pohangina 23d 55-6 Mata 41b 64 Pokaka 63a 52 Mataikona 23c 58 Pokapu 47b 65 Matakaoa 60c 52 Pongakawa 83a 51 Matamau 33b 59 Porirua 21b 55;tab.4-3-1;Pl.21,25 Matapiro 13a 100, 54, 58, 112; tab. 4-3-1, Potikirua 80a 59 4 5 3-4 5 5; Pl. 21, 25 Puhoi 38a 64, 100; 4 3 1; Pl. 22, 26 - - * - tab. - - Matawai 57e 51 Pukekoma 27b 81 Maungatua 43b 81 Pukemutu 15b 84 Mayfield 19a 81 Pukepuke 54b 56 Medina 15b 69 Puketeraki 25b 78, 101; tab. 4-3-1; Pl. 22, 26 Middlehurst 70a 117 Punakaiki 51b 75 Mokau 36b 54 Puniu 87b 62

138 Legend Legend symbol symbol Rahotu 87b 53 Te Rauamoa 62d 61 Ramiha 33c 55 Teviot 25b 78 Rangiora 41a 64, 106; tab. 4-4-1 Tima 4b 80 Rangitoto 96d 61 Timaru 8a 30, 80, 82, 101, 114; tab. Rangiuru 75a,b 65 2-4-1,4-3-1;Pl.7,8,21,25 Raukumara 37a 59 Tinopai 75c 65 Raumai 14b 54-5 Tinui 20c 58 Hill 55a,b 62, 67, 117 Tirau 62a 60-1; tab. 4 3 1; Pl. 23, 27 Red - - Renata in 33c 55 Titiraurangi 45c 85 Resolution 46b 85 Tokomaru 14a 54-5 Rimutaka 37a,b 56, 59, 116 Tokoroa 57a 51 Riverton 53b 86, 117 Tuhitarata 34b 59 Rockvale in 38d 64 Tuparoa 36c 59, 116 Rosedale 29b 70, 85 Turakina 23a 55-6 65, 101; 4-3-1; Pl. 23, 27 Rotomahana 96a 50, 100, 101; tab. 4-3-1; Pl. Tutamoe 75b tab. 24, 28 Ruahine 37b 56, 59 Ruakaka 84a 67 Ruapuna 19b 69-70, 81 Urewera 58b 52 Ruatangata 78a 66;tab.4-3-l;Pl.23,27 Ruatoria 36c 59, 116 Rukuhia 84b 63

Waiareka 67a 71, 82, 101; tab. 4-3-1; Pl. 24, 28 Sedgemere 8b 69 Waihi 60c 52 Selwyn 90a 72, 79, 83; 4 3 1; Pl. 24, tab. - - Waihopai in 10a 69 28 Walkakahi 49a 82; tab. 4 -3 -1; Pl. 24, 28 Spenser 46a 71, 78-9 Walkare 39b, 42a 62, 64, 101; tab. 4-3-1; Pl. I1, Spooner 29b 70, 85 22, 26 9a 81; 4-3-1; Pl. 21, 25 Steward tab. Walkiwi 27a 85, 115; tab. 4-3-1; Pl. 22, 26 Stewart 70a 82 Waikoikoi 16a 80 Stratford 65a 53; 4 3 1; Pl. 23, 27 tab. - - Waimahaka 29a 85 Struan 5a 77 Waimairi 81a, 85a 83 Summit 70a 82 Waimakariri 90a 72, 79, 83 Waimarama 31a 58 Waimate North in 78a Pl. 17 Waimatenui 74b 65, I 17; tab. 4 3 1; Pl. 23, 27 - - Tadmor 29c 70, 73, 74 Waiotira 38b,c 64, 116 Taihape 23a 55-6, 58 Waiotu 78a 66 69 Taita 34b 30, 55; tab. 2-4-1, 4-3-1; Pl. Waipara 8b 22, 26 Waipawa 13b 58 Wairakei 57b 51 Taitapu 88a, 92a 72, 83; tab. 4-3-1; Pl. 24, 28 Takapau 22a 58 Wairaki 27a 85 Takitimu 72b 86 Wairama 31c 62 Takitu 74a 65 Wairua 86b 67 Tangatara 58a 52 Waitakere 74b 65 Tangitiki 42c 64 Waitaki 3a 76 Tangoio 23d 58 Waitekauri 60b, 61a 52 66 Waiteti 57f 61; 4 3 1; PI. 23, 27 Taraire 79a tab. - - Tarawera 96b 50 Waitoa 87a 62 Taumata 38c,d 64 Waitohi Ila 80 Taupo 57a,b,c 30, 50-1, 59, 100, 106, 117; Waiuta 44a 73 Wakamarama 45b 74 tab. 2-4-1, 4-3-1, 4-4-2; 4-5-1, 4-5-2; Pl. 19, 23, 27 Wakanui in 92a 108 20a 114-5 Tautuku 43a 73, 85, 101, 116; tab. 4-3-1; Wanstead 58, Pl. 22, 26 Warea 64a 53 Te Anau 59a 86 Warepa 12a 80 Te Houka llb 80 Warkworth 39c 64 Te Kaha 60a 51 Wehenga 27b 81 66b 61 Tekapo 24a 77, 106, 115; tab. 4-3-1, Weymouth 4-4-1; Pl. 22, 26 Whakamarama 60b 52 Te Kie 76a 65, 67, 100, 117; tab. 4-3-1; Whakatane 57c 51 PI. 24, 28 Whangaehu 21a 55-6 Tekoa 26b 78, 115 Whangamata 61a 52 Te Kopuru 48a 65 Whangamoa 30a 70, 116 Te Kuiti 62b,c 61 Whangamomona 36a 54 Templeton 91a 72, 83; 4 3 1; Pl. 24, 28 Whangaripo 39a 62, 64; tab. 4 3 1; Pl. 22, 26 tab. - - - - Temuka 85a 83, 100, 101; tab. 4-3-1; Whareama 23b 58, 116 Pl. 24, 28 Wharekohe 47a,b 30, 64, 116; tab. 4 3 1, 4 5 1, - - - - Tengawai 10a 80 4*5-2; Pl. 22, 26 Te Ranga 40a 67, 116 Whetukura 31b 58-9 Te Rapa 87a 62 Windley 71a 86

139 CONTENTS OF PARTS 2 AND 3

PART 2

CHAPTER 6. Mineralogy of New Zealand Soils

6 I Mineral Weathering (by M. Fieldes) - *

6-2- Mineralogy of Sand Fractions (by M. Fieldes and A. V. Weatherhead) Range of Minerals in Sand Fractions; Mineral Assemblages in Parent Rocks; Mineral Assemblages in Sand Fractions; Conclusion; References.

6 3 Clay Mineralogy (by M. Fieldes) - - Introduction; Conditions of Clay Formation; Structure and Classification of Soil Colloids; Clay Mineralogy and Genetic Classification of Soils; Summary of Dominant Constituents in New Zealand Soils; References.

6-4- Amorphous Constituents (by K. S. Birrell and M. Fieldes) Introduction; Soils Containing Amorphous Constituents; Nature of Amorphous Con- stituents; Estimation of Amorphous Constituents in Soils; Conclusions; References.

CHAPTER 7. Soil Chemistry

7-1* Soil pH, Calcium Carbonate, and Soluble Salts (by R. B. Miller) Soil pH; Calcium Carbonate; Soluble Salts; References.

7-2- Organic Matter (by L. C. Blakemore and R. B. Miller) Introduction; Organic Matter; Total Nitrogen; Carbon/Nitrogen Ratios; Total Sulphur/ Nitrogen, and Organic Phosphorus/Nitrogen Ratios; Organic Matter per Horizon Acre; Chemistry of Plant Litters; The Organic Cycle; Conclusions; References.

7-3* Cation-exchange Properties (by A. J. Metson and L. C. Blakemore) Introduction; The Exchangeable Cations of Soils; Analytical Methods; Cation-exchange Properties of New Zealand Soils; Conclusions; References.

7-4- Calcium and Liming (by R. B. Miller) Introduction; Levels of Exchangeable Calcium in New Zealand Soils; The Effects of Lime on Soils; Liming New Zealand Soils; Quality and Rate of Application of Lime; References.

7*5- Magnesium (by A. J. Metson) Introduction; Magnesium Availability in Soils; Magnesium Status of New Zealand Soils; Conclusion; References.

7-6* Potassium (by A. J. Metson) Introduction; Potassium in Soils; Chemical Methods for Determining Potassium- supplying Power; Potassium Status of New Zealand Soils; Conclusions; References.

7-7* Phosphorus (by W. M. H. Saunders) Introduction; Total Phosphorus; Organic Phosphorus; Inorganic Phosphorus; Phosphate Retention; Phosphorus Uptake by Sweet Vernal; Conclusions; References.

7 8 Sulphur (by L. C. Blakemore, T. W. Collie, and A. J. Metson) - - Introduction; Analytical Methods; Distribution in New Zealand Soils; Conclusions; References.

7-9- Iron and Aluminium Extracted by Tamm’s Reagent (by W. M. H. Saunders) Introduction; Zonal Soils; Intrazonal Soils; References.

CHAPTER 8. Element Composition of Soils and Plants (by N. Wells)

8 1 Element Composition of Soils - -

8-2- Introduction Factors Influencing Composition; Relation to Genetic Classification.

8 2 Availability of Microelements - - Introduction; Iron; Manganese; Zinc; Copper; Molybdenum; Boron; Chlorine; Vanadium; Cobalt; Selenium; Iodine; Topdressing; Conclusions.

141 CHAPTER 9. Soil Physics and Engineering

9-1- Physical Data for Modal Profiles (by M. Gradwell and K. S. Birrell) Introduction; Physical Properties; Conclusions.

9-2- Ratings of Physical Properties for Soil Groups (by D. C. McDonald and K. S. Birrell) Introduction; Results; Reliability of Results; References.

9-3- ClassiScation of Soils on a Moisture Basis (by D. C. McDonald) Introduction; Method; Results and Discussion.

9-4- Correlation of Engineering and Pedological Classification (by R. D. Northey) Introduction; Methods; Results and Discussion; Conclusions; References.

9-5- Soil Corrosion (by H. R. Penhale) Introduction; Factors Affecting Corrosion of Metals; Factors Affecting Corrosion of Concrete and Cement Asbestos; Results of Field Tests of Steel; Results of Field Tests of Cement Asbestos and Concrete; References.

CHAPTER 10. Biology of the Main Soils

10 1 General Introduction

- -

10-2* A Preliminary Study of Soil Animals and Their Relationships to Some New Zealand Soils (by K. E. Lee) Introduction; Methods; Zonal Soils; Intrazonal and Azonal Soils; Discussion and Conclusions; References.

10 3 Algae on the Surface of Some New Zealand Soils (by E. A. Flint) - - Introduction; Methods of Study; Abundance of Algae at Time of Sampling; Distribution of Some Species of Algae; Effect of Base Deficiency on the Algal Community in Judge- ford and Taita Soils; Effect of Vegetation on the Algal Community; Conclusions; Acknowledgements; References.

10 Fungi in New Zealand Soils (by R. H. Thornton) -4 - Introduction; Methods of Study; Distribution of Species; Some Ecological Considera- tions; References.

10-5- Yeasts (by M. E. di Menna) Introduction; Methods of Study; Pattern of Distribution of Yeast Species; Conclusions; References.

10 6 Actinomycetes (by T. R. Vernon) - - Introduction; Methods of Study; Abundance and Distribution of Actinomycetes; Classification of Isolates; Conclusions; Acknowledgements; References.

10-7- Bacterial Flora and Microfauna (by J. D. Stout) Bacterial Flora; Microfauna; Interrelations of the Microfauna and Bacterial Flora; References.

PART 3

CHAPTER 11. Descriptions and Analyses of Reference Soils

11-1- Methods Pedology; Soil Physics; Soil Engineering; Sand Mineralogy; Clay Mineralogy; Soil Chemistry; Spectrographic Analysis; References.

11 2 Soil Descriptions and Analytical Data - - Abbreviations and Scales; Index of Reference Soils; Descriptions and Data; Litter Analyses.

I 1 3 Colour Plates of Reference Soil Profiles - -

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