The Soil Survey

The soil survey delineates the basal soil pattern of an area and characterises each kind of soil so that the response to changes can be assessed and used as a basis for prediction. Although in an economic climate it is necessarily made for some practical purpose, it is not subordinated to the parti­ cular need of the moment, but is conducted in a scientific way that provides basal information of general application and eliminates the necessity for a resurvey whenever a new problem arises. It supplies information that can be combined, analysed, or amplified for many practical purposes, but the purpose should not be allowed to modify the method of survey in any fundamental way. According to the degree of detail required, soil surveys in New Zealand are classed as general, . district, or detailed. General surveys produce sufficient detail for a final map on the scale of 4 miles to an inch (1 :253440); they show the main sets of soils and their general relation to land forms; they are an aid to investigations and planning on the regional or national scale. District surveys, for maps, on the scale of 2 miles to an inch (1: 126720), show soil types or, where the pattern is detailed, combinations of types; they are designed to show the soil pattern in sufficient detail to allow the study of local soil problems and to provide a basis for assembling and distributing information in many fields such as agriculture, forestry, and engineering. Detailed surveys, mostiy for maps on the scale of 40 chains to an inch (1 :31680), delineate soil types and land-use phases, and show the soil pattern in relation to farm boundaries and subdivisional fences. For special studies, particularly in areas of very intricate soil pattern, detailed surveys are made for maps of 20 chains to an inch or other larger scales. They are a direct aid in advisory work, and in many fields of research where the problems are linked with the distribution of individual soil units and modifications of these units induced by man's activities. The soil survey is considered under three ma_in headings as follows: Units of soil mapping and classification; General conduct of the soil survey; Soil classifications for special purposes.

UNIT~ Of SOIL MAPPING AND CLASSIFICATION The soll:mappingunits are necessarily closely related to the taxonomic classes of the soil classification and are named accordingly. Ideally the basal unit of both mapping and 133 classification is a simple uniform one containing a single other parts of the country. Thus 10 soil types belonging to kind of pedon so that tJie variations within th~ unit are no seven distinctive series may be grouped broadly as follows: greater than those withm the pedon. In practice, however. these ideal units are rarely large enough to be of general N orthem yellow-brown earths use when shown on s.oil maps. Consequently the actual Puhbi clay loam basic unit of soil mapping, the soil type, is generally a somewhat varied one; usually it contains an assemblage. of Riponui sandy clay like pedons with, in places, a smaller number of unhke ~ Riponui sandy loam pedons regarded as inclusions within the type. Northern podzols Soil classification in New Zealand has developed along two Wharekohe silt loam main lines - one based on the American system, and the Wharekohe fine sandy loam other, the genetic system, based originally on early Russian Wharekohe sandy loam work. The American method classifies soils into types, Parahaki silt loam series, and families. Its basic unit is the soil type which is given a composite name comprising a geographic name :to Northern red-brown loams indicate the series, followed by textural and other dis­ tinguishing names, and is subdivided where required into Kiripaka silt loam phases on the basis of characteristics potentially significant Whatatiri friable clay to land use. It has the advantage of providing simple refer­ Ruatangata friable clay ence names for the use of advisory workers, farmers, and others dealing with the land. The genetic method classifies soils in an interpretative way, according to groups of soil­ The Soil Type forming processes (p. 157) . Its basic unit, which is a The soil type is the basic unit of soil mapping. In the narrow one containing a single kind of pedon, is given a field an endeavour is made to subdivide the soil covering descriptive name in terms . indicating its genesis. It has the an area into a number of homogeneous or near-homogeneous advantage, as a research tool, of enabling the student to segments so that these may be classified and predictions classify and name the soil of any particular site without made as to their behaviour under various conditions. Each of reference to a central correlating authority, in terms that these segments is a soil type. readily convey to others an understanding of its nature. Each soil type is a unique combination of internal The soil types, series, and families of the American system characters and site features which are assessed in the field correspond in an approximate way with appropriate lower and in the laboratory by chemical, physical, biological, and categories of the genetic classification; for ordinary purposes mineralogical studies of the soil horizons including the parent they can be classified in the genetic system by naming the material, and by examination of the form and other modal* part of the type, series, or family, as is commonly characteristics of the site. The endeavour should be to done for the higher categories. In soil surveys the mapping select a homogeneous soil unit rather than a unit which units are generally expressed as soil types and series, and are merely has certain uniform soil-body characters. arranged in groups according to the common names of the genetic nomenclature, in order to show the relationships The problem of recognising a soil type calls {Qr good that link the soils with one another and with the soils of judgment on the part of the pedologist, just as recognising a species requires judgment on the part of the biologist. But *When referring to a soil or profile, modal is used with the mathe­ biological units are commonly disposed in distinct steps matical meaning of "the most abundant" as distinct from medial which refers to the middle of a sequence. Such profiles should not with the intergrades missing, whereas soil units commonly be confused with the general soil. profile which is commonly merge into one another with smooth gradations ( see p. 14) . reconstructed from many observations, portrays the salient features In both cases the problem lends itself to the manoeuvrings in a general way, and is sometimes termed a constructed universal. of the "splitters" and the "Jumpers" (see Appendix 14). To 134 maintain uniformity in recognising a~d e~tablishing soil types standards established on earlier pages. The nomenclature the following points should be borne m mmd: is illustrated by the following examples: Timaru silt loam; Kerikeri friable clay; Waimakariri stony 1. "Any one soil typ~ i!}cludes the soils that are ali_ke . ,in sandy loam; Waimakariri shallow sandy loam; Egmont black characteristics that are s1gmficant to the na'11;1fe and functiornng silt loaqi; and Hokio strongly mottled sand ( all the soils of the of the soil in the natural landscape." (Umted States Manual, Hokio series are mottled, the name indicating the degree of p. 12). Differences that are not signifi~ant in the natura~ ;l~nd­ mottling and associated conditions in this particular type) . scape, but which are significant to special crops, are subd1v1S1ons within the type. Historically, soil types were named according to the series 2. Where the soil type consists of more than one kind of pedon and the texture of the topsoil only, and in New .Zealand it must be capable of being describe~ ~n terms of a modal pedon those distinguished by additional terms were regarded as together with pedons that are trans1t10nal to modal pedons of subtypes. Since, however, the type should include all its other types. The variations within a type should not he greater subtypes, this system involved more complex terminology, than the differences between it and other types, and there sho~ld not be too many pedons in one type ·that are capable of bemg for which there were no grounds other than historical. equally well placed in another. Consequently such subdivisions of the series are now re­ 3. All parts of a soil type have like site c~aracteristics ( cli~a~e, garded as soil types. topography, parent material, etc.) and like mternal charactenstics (arrangement and kind of soil ~or_izons, colour, tex!ure, structure, chemical composition, etc.). Vanah~n must necessanly be all?wed, The Soil Phase but it should be narrow. The soil typ~ should be suffipeat sods, sd_ted and flooded phases m lower levels of classification. As with the soil type, good subdividing recent soils of alluvial flats, and so on. The practical judgment is necessary if series are to be established phase names are placed afte~ the soil-type name as fol~ows: in a sound and useful manner. Oxford silt loam, easy rollmg phase; Mata clay, slightly At one time it was thought that soils of a series should eroded phase; Rukuhia peat, burned phase. be identical in profile, excepting only differences in topsoil texture. Upon this concept was founded the existing system of naming soils using a geographic name to denote the The Soil Variant series combined with a textural name to denote the type. The soil variant should be clearly distingu!shed from t~e Differences in topsoil texture, however, are mostly soil phase. It is a unit of conve~ience, designed. to avoid accompanied by other differences in · the profile. Such a unnecessary multiplication. of. sen~s n~mes. It 1s cl?sely concept therefore is too simple, and if strictly applied related to the soil from which it derives its name: but. differs would result in the formation of a large number of unitype in characteristics at the same . level o! ~lassification. ~t series. This would not only defeat the purposes of the series permits the soil surveyor to avoid e~tablish1~g se~r~te so~l grouping, but also, in a varied terrain like New Zealand, types for soils of minor . extent w1th~ut 1eopardismg his would result in a multiplicity of series names too cumbersome narrow definition of the senes; thus a sod may be defined as for any practical purpose; a new category with a simple a variant in one survey, and later raised to t~e rank o~ a nomenclature suitable for advisory workers and others would separate series when found to be more e~tens1ve. By usmg then be required for grouping the like unitype series. the term variant, the soil surveyor t~lls_ his r~ade_rs that he Special care should be taken, in dealing with soils on recognises in the profile enough cr1tena to JUShfy a_ new alluvial plains and on hilly and steep land, to ensure that series but for one reason or another 1t cannot be conveme~tly series names are not multiplied unnecessarily. Usually the established. As with the phase, the variant may be al?phed soils of such terrain are so varied in detail within a small at other levels of the classification should the need anse. compass that no useful purpose is served by creating numerous, narrowly defined series. Too many field men are over-intent on drawing attention to differences; it is equally The Soil Series as important (although more difficult) to stress similarities. The soil series is a grouping of soil typ~ with si~ilar particularly where these are likely to be reflected in a wide modal profiles, similar temperature and mois~ure regnne~. variety of land use. and the same or very similar paren! material~. In Ne:V The series is given a geographic name indicating a locality Zealand it is. used with a somewhat wider mea1;1mg !ban m where it is well developed, or in some instances the locality the United States. Types within a series may differ m s~ch where it was first recognised. The geographic name should characters as texture, slope, stoniness, degree of erosion, be a well established one; where a name is duplicated in topographic position, and depth to ~rock, where these another part of the country, it should preferably be used characters do not greatly modify the kmd and arrangement as a soil name in the locality that is most widely known. of soil horizons. the published list of post offices being a useful guide. The In New Zealand and the United States, the soil seri~ ~y modal type of each series should have a defined type itself is seldom used as a mapping unit iJ?- s~il surveys: I! 1s locality where the characteristics of the series can be in­ not sufficiently homogeneous for . the ob1ect~ves of detailed spected; these type localities should be recorded in reports soil surveys, and on more generalised maps 1s usually better for the guidance of future workers. 138 139 The Soil Family mappable units should be so constituted that, for the The soil family is a grouping of like s~r~es at a l~vel below objectives of applied soil science, it can be simply phased the main soil group. The need for recogmtion of this _category for ~uch characteristics as slope, stoniness, and degree of is shown by the common tendency t~ extend a senes name erosion. to include the soils of several senes, for exan:iple, ~he The~name of a soil family is taken from the name of a frequent references to Kaikoura-like and Haas.t-hke smls. leading series, preferably a median one. In order to avoid Although attempts to establish the soil family have _been confusion with a series name, it should have a distinctive made in some districts, it has not yet been estabhs~ed e_nding, preferably adjectival as in the stage names of biostra­ satisfactorily in New Zealand, but it appears to be evolvmg !1graphy, where for example the geographic name Nukumaru as a class somewhat below the level of Category V of the 1s used for the Nukumaru formation but is changed to genetic classification (p. 169), formed of like ~eries by Nukumaruan in order to designate the Nukumaru stage parcelling together similar kinds of parent maten~l; such (Fleming, 1953, p. 103). families retain the major differences among senes. !'he findings of the United States Soil Survey Subcommittee The Soil Complex dealing with soil families (United States ~anual, p. 301) as applicable in New Zealand, are summarised as follows: 1:he_ soil coI?plex is a compound mapping unit containing an mtimate mixture of two or more so1t-lypes- or series that In diverse soil regions a ~ombinatio1:1 of thr~ or more of c~nnot 1?e differentiated on ordinary detailed soil maps. the following criteria has given tentatively satisfactory sub­ Smee soil complexes do not form a category in the soil division of the main soil groups involved: classification, it is wrong to give them separate taxonomic 1. Kind and sequence of h~rizon~ within the ma~!er names. They s.hould be allotted composite names derived horizons that define the mam soil groups. Fam1hes from the names of their principal constituent units joined separated on these criteria expres~ the _median concepts of by a hyphen, for example, the Horotiu - Te Kowhai complex main soil groups and of the vanous mtergrades between which includes not only the types indicated but also inter­ grades between them. them. 2. Relative degree of horiz~n differentiation - the de~r~e Since a soil complex cannot be defined in terms of a of expression of master hor12ons that are charactenstic modal profile and its variations, its ·constituent units should of a specific main soil group. This co':ers in part the be ~~scribed as _if _they had been mapped separately, and in differences that were formerly expressed m New Zealand ~dd1t10n a descnption of the pattern s.hould be given, includ­ as "stages of soil development". mg the percentage occupied by each unit. These descriptions 3. Mineralogy of the solum - major mineralogical di~er­ can be illustrated usefully by very detailed maps of small ences associated with strongly contrasting parent matenals, sample areas on an unusually large scale. particle size distribution, or kind of clay (but within the limits of the main s.oil group). Hill Soils and Steepland Soils 4. Relative "size" of the solum - such as differences in In New Zealand where more than _two-thirds of the land thickness of the solum not associated \vith degree of surface is steep or hilly, special mapping umts re used in expression of the master horizons. order to permit soil mapping at a reasonable pace, to avoid Criteria 1 and 2 provide homogeneity of kind, sequence, over-multiplication of series names, and to express the relation and degree of expression of the horizons. Criteria 3 and 4 between hill soils and their counterparts on rolling or steep appear to be below them in level of abstraction. In trial slopes where this relationship cannot be properly expressed groupings made in the United ~tates, many of. the character­ by phases. istics dropped between the senes and t~e fanuly levels were Where the angle of the slope varies but parent material primarily functions of the parent maten~l not fully reflected and other soil-forming factors are reasonably uniform, there in the criteria listed above. The family as a group of is generally a gradation of soil properties that is correlated 140 141 with the angle of slope; the soils can be arranged in a surveys and for generalised compilations from existing de­ simple toposequence which on areas of hilly and steep land tailed maps, and it is especially useful • where it recurs gives rise to somewhat intricate yet predictable patterns of repeatedly in the landscape. According to the purpose and soils. Thus in most places the soils on the rolling land are scale of the map, it is used at different levels. of refinement, well developed and reasonably uniform; those on the hilly the constituent units being chpsen at the appropriate level of land are more varied, some being rather similar to the soils on classification. Thus associations may show combinations of rolling land and others less developed; and those on the soil types, series, main soil groups, or other soil classes. steep land are still more varied, with a greater proportion of Soil associations are named and described · according to soils that lack well developed horizons. their constituent units and the nature of the soil pattern, in By convention, complexes of this kind with soil patterns the same way as soil complexes, the more important soils dependent upon a single toposequence are not given com­ being classed as dominant, co-dominant or subdominant posite names. Generally on hilly terrain they are named according to the relative area that they occupy. after their rolling counterparts if these exist, and on steep land they are named according to the modal soil of the steep The Soil ~ ------slopes (with angles of slope ranging approximately from ~ l set is a convenient mapping umt sed on general 28 to 38 degrees); the sequence of soils formed from surveys m New-Zmarrd-and-is a-grouping of soils with like weathered greywacke under northern rain forest, for example, profiles or like assemblages of profiles. Its constituent soils is Mama clay loam, Marna hill soils, and Te Ranga steep­ need not be geographically associated, and small areas of land soils. In places, however, the soils formed on hilly other soils within its perimeter are disregarded. Sets are terrain resemble those of the steep land more closely than chosen as far as possible to meet the practical objectives of those of the rolling land, so that the main break in the soil the survey and are not necessarily of equal pedologic rank. sequence comes between the hilly and rolling land rather than between the hilly and steep land; in such cases, the It has been customary to give the set the geographic name hill soils are named after their steepland counterparts. In of one of its leading soils. However, this simple nomen­ naming steepland and hill soils, the textural name is generally clature is confusing where the set contains two or more omitted, since soil slope is more important and textures soils with well established names, and in such circumstances tend to be varied, but textural or other names can be added composite names are preferable. when necessary to distinguish between two or more soils Although evolved as an expedient for rapid wartime bearing the same ·geographic name. The convention of non­ general surveys, the flexible groupings of like soils ·classed as composite naines for hill soils and steep land soils does not sets are useful for many practical purposes since, excepting apply where differences in parent material or other soil­ those indicated as complex assemblages, they can be defined forming factor give rise to soils of more than one topo­ in a broad way in terms of a modal soil and variations from sequence within the mapping unit. For such units composite it. names are necessary as for ordinary soil complexes. Undefined Soil Groupings It is sometimes expedient to indicate the distribution of The Soil Association certain soils on a map in a less definite way than is required The soil association is a compound mapping unit com­ by the soil association or complex. These soils may be monly used on generalised soil maps and consists of a grouped into relatively large areas, as for example on steep pattern of geographically associated soil units; each of these rocky terrain of little economic importance where a time­ is named and described, and the proportion of each lies consuming examination of the pattern is not justified; or within limits that are defined. The soil association is essen­ they may be grouped into smaller areas, as for example tially similar to a soil complex but for the most part the where their relationship to other units is obvious and the pattern is sufficiently coarse to be resolved on ordinary establishing of special associations or complexes for each detailed maps. It is employed as a mapping unit in original one of them would make the legend unduly complicated. 142 143 Such areas are usually indicated on the map by multiple requirement to enable the soils to be mapped in classifiable symbols connected by "+" (for example TK + H) where units as they are encountered so that field work can proceed the symbols represent distinct soil units, and by " - " ( for systematically; it can be added to and revised as the survey example TK - H) where they represent related soils passing progresses. The units of the legend should be suited to the into one another by a smooth transition. In the soil report, detail f the natural soil pattern as well as to the scale of these areas are described appropriately under the relevant the map and the purpose of the survey (see p. 133), other- units for the constituent soils, special mention being made . wise they are likely to be stretched beyond their conventional of the more important areas. definitions and parts of the map are likely to become Small areas of prominent soils are commonly shown on confusingly detailed. a map by means of symbols without drawing boundaries, for example, the soils of saline, swampy, rocky, and strongly Base Map eroded areas. This device is used also on small-scale maps The base map for the survey should be a properly to denote the soils of areas such as river flats, which, controlled one capable of being fitted with other maps. It although too small to be separated on the scale used, are should be appropriate for the survey and have sufficient detail of real significance to land use. to enable the soils to be shown in relation to base data, for example, to enable soil boundaries to be correctly placed in relation to streams, roads, buildings, and other topographical CONDUCT OF THE SOIL SURVEY features. For detailed surveys, it should show such features as villages, farm boundaries, drains, and plantations, which Preparation for Survey are necessary to enable the final map to indicate land use in The kind of survey and ·the scale of the soil map should relation to soil. The base data are checked and amended as be carefully considered and decided with finality before necessary during the progress of the survey; soil boundaries mapping is commenced. If this is not done correctly the that are difficult to trace without a resurvey, owing to meagre project cannot proceed smoothly and will be the subject of base data, lose much of their practical value, and are a delays and frustration. constant source of annoyance to users of the map. The geology, geomorphology, and Pleistocene history of Base maps may be larger in .scale than the final map but the area, where known, are valuable aids to the understand­ should be drawn so that they are readily reducible to the ing and hence the mapping of the soil pattern. Where they final scale for publication. A large-scale base map is used are not available, the relevant facts needed to explain the by some soil surveyors because it allows ample room for the soil pattern are obtained as the survey proceeds, since a soil data to be clearly drawn. It has, however, the serious knowledge of the soils themselves is a valuable aid ·in disadvantage that it tempts the inexperienced soil surveyor elucidating the past history of the land surface. After con­ to clutter it up with detail that interferes with the compilation sulting geological and other maps and reports that give of the final map, thus defeating the initial purpose of the relevant information about the area, a reconaissance is made, survey by distracting attention from the need to choose noting the major soils and examining key areas in some appropriate units. As a consequence, it is often the cause ·of detail, in order to gain sufficient information to draw a repeated requests for enlarging the final scale of the map preliminary skeleton legend and decide on the kinds of after the survey is well advanced. Base maps on drawing paper units to be mapped. Whatever fluid devices are used for the are preferred by some, since they are easily handled and can legend at the beginning of the reconnaissance, by the time be coloured as the work progresses. Transparent base maps the preliminary inspection is completed and before field are preferred by others to permit data to be transferred mapping begins, the framework of a controlled working directly, and also to allow sun prints to be made directly. legend of soil units as such should be drawn up, and not for preliminary distribution and other purposes. Base maps merely a scheme of soil-forming factors or soil characteris­ that have not been adequately prepared can give rise to much tics . th~t allows multitudinous combinations. Inevitably this avoidable delay, and consequently the time spent on carefully prehmmary legend will be incomplete, but it is an essential preparing them is time well spent. 144 145 Field Work and Soil Register Land-use Correlations In general and district surveys. the boundaries of the main topographical units of the landscape are commonly the first ~lthough the soil survey. as explained on page 133, is not sketched on the map. followed by the boundaries of soils of itself a land-use survey. it is the basis of determining the within these units. advantage being taken of site features such p~ttem o! best land use. but only when taken in conjunction as microrelief. plants. and drainage. that are found to be with soeial and economic factors* ( cf. Kellogg. 1959a). correlated with the soils. In these surveys soil boundaries are Problems of utilising unused land. of improving present determined at fixed locations with spade and auger (see page use. ?r of selecting land suitable for some specific crop are 129); between these locations the boundaries are sketched questio~s of moment in newly developing countries. In with the aid of secondary evidence. They are not traversed attemptmg to solve problems of this kind, the first step is throughout their length as is virtually done on detailed sur­ to undertake a soil survey so that any available experience veys. Commonly roads are traversed first and additional cross­ can be transferred to the sites in question from other sites country traverses are made as required. Where air photos are with identical. or_ simila~ soils. Where such experience is well available. the mapping is frequently done on these. as they d?cumented. 1t 1s possible not only to predict some of the show many features such as topography. geologic structure. kmds of l~nd use for which the soil is naturally suited. but differential soil-moisture effects. and pattern of land use. that also to estimate the potential production at say three levels - can be correlated with soil conditions. Results are replotted the average production per acre of used areas; the production on to the controlled base map. area by area. as the work of the. best 10 pe~ cent of. the land users ( a relatively easy continues. In detailed surveys. where the soil is examined poten!1al for which to aim); and the production from field by field and farmers need to be interviewed in succession expenmental plots where limiting factors have been amelior­ the mapping is most conveniently undertaken farm by farm: ated as far as knowledge permits. Where experience is incomplete or lacking. it is possible As. t~e s_urvey proceeds. a soil register should be made. to attempt predictions from the · basal requirements of the contammg m summary form the relevant information about plants to be grown. Although these requirements are different each soil unit. Separate sheets are added for each unit as for different plants. the higher plants require of the soil established. and information is added periodically from field seven cardinal conditions for satisfactory growth. They need: books and other sources as it becomes available. If this ( 1) a site which is relatively stable and where competition register is kept systematically and revised from time to time from other organisms is not too severe; (2) suitable conditions the i1:1formation requi_red for the soil report is compiled by of soil temperature. and of (3) soil air; ( 4) soil water; and !he time. field work is completed. A guide to the kind of (5) root penetrability; (6) adequate supply of nutrients. mformatlon re~rded f~r each ~oil in the register is given including possibly some related growth-promoting substances; by the followmg headmgs which were used in a North and (7) relative freedom from toxins (Taylor. 1952). Too Auckland survey: often in the past. a soil has been condemned as unsuitable Name of soil unit Local name for crops without careful consideration to discover which of Mapping symbol Present use these seven conditions are unsatisfied and to what extent they Classification Present cover could be modified. Generally. the soil nutrient status is Profiles (modal and variations) Topdressing practice easiest to modify by the relatively simple expedient of adding Parent material Responses on experimental plots fertilizers. In many place$ soil air and soil water can be Relief and elevation Potential uses modified teadily by such practices as drainage and irrigation. Climate Productivity (average, best far- The other conditions are usually more difficult to deal with. Native vegetation mers, and experimental plots) the soil temperature regime being one of the most impractic­ Drainage Factors limiting productivity able to modify on a large scale (Taylor. Dixon. and Pohlen. Natural fertility Erosion 1955). Type locality, distribution, and Water supply *Land utilisation and other land surveys are based on economic and area (acres) Additional notes socia! conditions as well as on soil capability. Hence they are more Sample data transient than soil surveys, the mapping units of which are based on existing soil properties alone. 146 147 Whenever possible, the soil survey party works in ~lose cooperation with specialists in land use and other subJ~cts, of significance to land use such as sand d_unes, stones: and who supply the additional information needed to achieve boulders are indicated where appropnate by smtable the final objective of coordinating the soil survey and land­ stippling; which may also be incorporated in the soil use data. Thus in an agricultural district, the party cooperates colours. The boundaries of soil units that merge gradually with the local advisory officer, who is brought into the project into e>ne another through broad transitions, owing to a at an early stage and takes part in the preparation of the final gradual change in climate or other soil-forming factor~ are report; in a forested area it cooperates with an officer o~ th_e shown by dotted lines; this distinguishes the~ from ordm~ry Forest Service, in an orchard district with the local horti­ soil boundaries which indicate narrow transit10ns and w~1ch cultural officer, and so on. are shown by broken lines. All these symbols are shown m a map reference together with the topographic symbols. Preparation for Publication The soil units are identified by symbols, either letters or numbers. For this purpose l~tters hav~ ~he great adv~ntage of After field work has been completed, the soil map and flexibility in that they permit the pos1t10~ of the soil on _the report are prepared for publication. This is the final stage legend to be changed without upsettmg the numerical of the soil survey. In practice it has proved a difficult stage, sequence, and also allow a symbol to be use~ again for the partly because not enough preliminary compilation is done same soil on other maps; but they are not easily found on a during the course of the survey, and partly because of the long legend, nor do they permit s~cient co~binations to natural reluctance to abandon ideas that cannot be substan­ give each of a large number of soils appropnate symbols tiated without additional investigations. Such investigations that are easily remembered. Numbers have the advantage of are properly not a part of the soil survey but are rather being readily found on the legend but ~hey _cannot be all~­ the subject of recommendations for future projects arising cated before the legend is completed; if. this done, and If from it. Until the work is published, the informati0n obtained their position on the legend is changed o_wmg to l~te chan~es by the soil survey is relatively inaccessible and for the most in classification, the numerical sequence 1s upset with the nsk part cannot be used without interpretation personally by the of perpetuating mistakes in the published report. For these soil surveyor. Consequently, the preparation for publication reasons, the soil units are indicated by letter symbols where should be finished without delay and before the departure of practicable, esp_ecially on detailed .or other surveys of s~a!l essential members of the survey team. areas where soil legends are relatively short; they are md1- cated by numbers on general or other surveys of large areas Soil Map and Legend where the legends are long. The soil map shows reference inf?r~ation n~eded by !he In New Zealand, separate colours are rarely allotted to reader to identify it, basal topographic mformat10n, supenm­ each soil unit. Usually the same ~olour is given t~ soil~ ~at posed soil survey inforr1!ation, and ~pproIJr:iate legends. For are closely similar, the symbol bemg the means of 1den~1fymg identification purposes, It has upon It the title and date, the the individual soil unit. Colours are used as a gmde to name of the publication that it accompanies or the reference identification of soil areas, and as an aid in grouping similar number, and suitable acknowledgments to the soil surveyors soils on the map. They are arranged according to the. broa~ and others responsible for the information that is shown. pedological classification. On maps' where all the mam soil For orientation and location it gives clearly the direction groups are represented, the basic colours conventionally used of north and the scale of the map (areal and linear), and are: contains small-scale diagrams showing the position of the Green -Brown-grey and yellow-grey earths (bluer shades map in relation to New Zealand and the position of ·each for brown-grey earths) sheet in relation to others. Brown - Yellow-brown soils (except yellow-brown loams) Red - Yellow-brown loams Since slope has an important influence on land use, steep­ Purple -Brown granular clays land and hilly soils are indicated on the soil map by vertical Blue - Red-brown loams and diagonal hatchings respectively, and where possible these Grey-brown - Podzols hatchings are incorporated in the soil colours. Other characters Yellow -Recent soils Orange - Gley and organic soils 148 149 The lighter shades of these colours are allocated to the less of the soils; and land use as related to the soil pattern. In leached or less developed soils of each group and the darker many reports, precise technical material which for many shades to the more leached or more developed soils. In this readers is difficult and unnecessary, is amplified in a separate way broad sequences within the main groups are indi~teci as section. well as the main group itself. On some maps, grey is used for steep land soils, indicating that steep skeletal and other weakly developed soils are in an integral part of the steep­ SOIL CLASSIFICATIONS FOR SPECIAL PURPOSES land complex. For the benefit of users of the maps, a standard For special investigations and land-use purposes, there are basic colour is adopted for each main soil group as far as many ways of systematically arranging the soils other than practicable; but if followed strictly on many district and in the taxonomic classification. For special land-use purposes, detailed maps where a large number of different colour they may be arranged advantageously according to the soil separations are required, this would lead to difficulties in properties that are most relevant. Grassland advisory experts printi:tg and to the production of maps difficult to read and commonly state that there is no significant difference between drab m appearance. On such maps, leading soil groups retain two soil types delineated on the map: what they mean is that their conventional colours and others are given the colours there is no significant difference in management methods and best suited to the particular map. yields when the soils are used for grassland farming, say To meet the requirements of the many users of the map, dairying; but this uniformity in management methods may not the soil legend is usually set out in two ways. For those who necessarily apply when the land is used for other purposes, think of soils in relation to land forms, it is arranged say, for fruitgrowing. Consequently, in order to meet the needs physiographically, the soil units being classified according of special kinds of land use, or of particular practices such to the land forms with which they are associated. For those as topdressing or drainage, the soil units are conveniently who thi~ of soils in terms of their similarities, it is arranged regrouped according to the properties that show correlations ~olog1~ally, the soil units being classified in terms of the with the particular land use or practice under consideration. mail!- soil groups (for example, see Cutler, Richards, and In the investigation of soil processes and related problems, Collie, 1957). the soils may be arranged advantageously in sequences. In this way the facts known about one soil are arranged in rela­ tion to the corresponding information about other soils in the Soil Report sequence, enabling progressive relationships to emerge. A The soil report and soil map together provide an indepen­ soil sequence may be arranged according to one of the prime dent reference to the significant information on soils and land soil-forming factors, or according to some narrower criterion use acquired by the soil survey and cooperating organisations. which is allowed to vary in a known way. Usually the object When published, they are permanent records allowing the is to keep one or more factors constant, in order to study public to have access to this information without the need for the effects of the factors that are allowed to vary. Thus, consultation with those who were employed on the original soils under study may be arranged in rainfall sequences, work. They are published in a form that is suiiable for parent-rock sequences, or drainage sequences according to advisory officers and students who are basing their studies on progressive differences in rainfall, in rock composition, or in soil and, as far as reasonably practicable with a technical drainage. subject, for farmers and others who are directly using the land. The body of the report should be neither so technical The Soil Suite as to be understood by a limited group only, nor so simplified Soil development sequences that have proved of value in as to have little value for the scientific worker. many investigations are the soil suites. In these, the parent The general order of the contents in published bulletins is rock or in certain cases the parent material is kept as constant usually on the fc_>llowin~ lines: purpose; general description of as possible and the soils from it are arrang:ed p~ogressively the area; the_ so1l-formmg factors such as climate, vegetation, according to the degree of development of soil honzons. Such parent matenal, and topography; description and classification arrangements allow the characteristics inherited from the 150 151 parent material or parent rock to be distinguished from those massive quartzo-feldspathic sandstone, a sequence of soil acquired during soil formation and from induced charac­ development due largely to progressi~e differences in the teristics that do not affect the profile as a whole but are original vegetation which ranged from d1cotylous-podocarp to lesser modifications due generally to man's cultural activities. kauri forest and to scrub after kauri (fig. 16). In the early Normally suites are confined to one general geographic thirties go~d information from farmers' experience and environment, for example, humid subtropical North Auck­ experimental plots was available for farmmg an early land, or subhumid temperate Marlborough. Extended suites­ member of the suite, Waiotira clay loam, and a late memb_er, may · however embrace sequences extending across sev~ral Wharekohe sandy loam. On the Waiotira clay loam, which major geographic environments, for example, the progression had retained much of its fertility from the forest burn, pastures from high-country yellow-brown earths through southern and were shown to respond to lime and phosphate topdressings central to northern yellow-brown earths. In making suites, but the responses were slow. Wh~n cultivated, t~e s?il yielded parent rock and proximate parent rock are grouped together a coarse tilth that required considerable consolidation before for many purposes. For many detailed investigations, the pastures could be re-established. By contrast, the Wharek~he suites have to be refined by subdivision into minor suites soil was exceedingly infertile in its natural . sta~e, g_rowmg based on finer differences in the composition of the parent little beside low scrub and fern. After cultivation 1t con­ rock or parent material; for example, the soils derived from solidated naturally to form a reasonable seed bed, and the olivine basalts may together comprise a suite, while those sown pasture responded quickly to lime a1;-d. pho~phate from a particular kind of olivine basalt form a minor suite. fertiliser; less lime was required than on the Wa10tira soil, but Not all suites can be shown as a simple linear arrangement of on the other hand the added lime was more critical for soils, and in many cases more complex arrangements are successful pastures. As the need for lime and phosphate was necessary to show clearly the dominant and subordinate satisfied, potash quickly became 3: limiting f~ct?r. At-that sequences involved. Thus, in the suite based on arkosic time the middle members of the suite (the Wa1otira clay and greywacke and comprising yellow-brown earths, podzols, and the Ripoimi and Hukerenui soils) had reverted largely to their intergrades, the sequence of yellow-brown earths to low-producing pastures and second-growth scrub, and the podzols is dominant, but, owing to differences in drainage, last member - the Wharekohe soil with pan..::_ was not used many of the soils lie on subordinate sequences, forming sub­ at all. On arranging the soils of the district in suites, it became suites that branch off the main one. obvious that the problems involved in utilising the Waiotira In defining a suite, the kind of parent rock ( or in certain clay, although accentuated, were essentially the same as cases the parent material) upon which it is based and the those of the Waiotira clay loam. On the Riponui and range of soils that it embraces must be indicated. If a specific Hukerenui soils the problems were progressively more like name is necessary, it should be derived from the names of those associated with Wharekohe sandy loam, but the the main soils of the suite (preferably the first and last members) as for complexes and associations. The majority of the coastal soils of the Manawatu district, for example, can be arranged in the Waitarere-Omanuka suite from coastal sands; this covers the sequence of yellow-brown sands to sandy gley soils together with subsuites covering part of the sequence from regosols to yellow-brown earths (Cowie and Smith, 1958, p. 39). This main suite may be subdivided into minor suites, such as the Foxton-Pukepuke suite which covers Waiotira Waiotira Riponui Hukerenui Wharekohe Wharekohe clay loam clay sandy loam sandy loam sandy loam sandy loam the sequence of yellow-brown sands to sandy gley soils formed with pan from very weakly weathered coastal sands (loc. cit., p. 18). FIG. 16. Main members of Waiotira-Wharekohe suite, North The usefulness of the suite classification is illustrated by Auckland: a sequence of soils from yellow~bro:"n earths to the Waiotira-Wharekohe suite; this is a sequence of soils, podzols formed from massive sandstone. S011 d1ff erences are from northern yellow-brown earths to podzols, formed from due largely to the former forest cover. After C. F. Sutherland (Taylor, 1952). 152 153 proximity of the clay subsoil to the surface created ':Vaiotira­ Summary of the New Zealand Genetic Soil like problems in cultivation, while on the pan_ va~iant, _the problem of drainage was more acute. By cons1denn~ smtes Classification* in this way, the future pattern of land use for the sods, and many of the practices required, were predicted (Taylor and The" genetic system of soil classification, as used in New Sutherland, 1936; Grange, 1939). In 1950 A. C. S. Wright Zealand, was based on the limited amount of Russian work and H. Breen, using the Aspergillus niger method, showed that was available in the early thirties. Since it was ~evelo~d that earlier members of the suite were high in "available" in comparative isolation from the rest of the world, 1t cont~ns copper content, the middle members moderate to low, and the concepts that differ in varying degrees from those on which later members very low - demonstrating that the suite classifi­ the main soil classifications overseas are based. Its nomen­ cation could be used as a basis for investigation of minor clature is also somewhat different, owing to the difficulties elements. The suite approach was subsequently used with that hindered correlations between the main groups of success by Wells ( 1956, 1960). As an aid in forming so~l different countries and to the confusion resulting from suites in New Zealand, a classification of parent rocks 1s conflicting correlatioi:is suggested by th~ all t?o few visiting given in Appendix 4. pedologists. These differences are steadil_y bemg resolved as liaison becomes closer among pedologists throughout the world. Correlations between soil groups recognised in New Zealand and their overseas equivalents are gradually becoming more definite. the chief soil groups on normal sites after acidic parent rocks are: the brown-gr~y earths, w~ich are approximately equivalent to non-calc1c brown soils; ~e yellow-grey earths, which are in part grey-brown podzohc soils with fragipan, but in part are only weakly clay illuvial if at all; the high-countryt yellow-brown earths, which are, in the main, subalpine acid brown soils; the southern and central yellow-brown earths, which cover a sequence of temperate soil~ fro~ brown earths to acid brown soils to grey-brown podzohc soils; the northern yellow-brown earths, which are for the most part subtropic red-yellow podzolic soils or yellow earths; the central and southern podzols, which in their various forms correspond clos~ly with those found overseas; and the northern podzols, which are subtropic podzols and in part are included in red-yellow podzolic soils by some overseas authorities. Of the other soil groups recognised, the rendzina, gley, and organic soils are approximately equivalent to the over­ seas groups with the same names; the yellow-brown sands

*Extracted from Taylor and Pohlen (1968). . tNorthern, central and sou.them, high couJ?-try, etc., are conve_ment local terms in common soil names used w1thm New Zealand 1tse'lf, but the more widely known equiv~lent_ terms s1;1btropic, ~emperate, subalpine, etc., are more appropnate m referrmg to soils of the New Zealand sector, which extends from the antarctic to the tropics. 154 155 cover a sequence from regosols to acid brown soils on coastal down slope by gravity, and removals by wind and water), sands; the yellow-brown pumice soils and yellow-brown accumulation ( colluvial, alluvial, and air-borne), and mixing loams from volcanic ash of finer texture are related to the (by such means as expansion and contraction) . ando soils, the pumice soils being the more regosolic; the red-brown loams and the brown granular loams and clays are derived from basic and intermediate rocks, some being latosols or latosolic soils, particularly in the north, and some having strong affinities with other groups; the recent soils CATEGORIES OF THE CLASSIFICATION from alluvium are equivalent to the alluvial soils of overseas pedologists; and the recent soils from very young or actively The higher categories of the New Zealand classification accumulating volcanic ash are regosolic or have regosolic A are subdivided according to the following criteria: horizons. Category I - basal form of the soil body; In arriving at the soil classification, many soil terms Cateogry II - main energy status as indicated approximately by tended to be used in a local sense not completely acceptable the ·latitudinal and altitudinal zones and by soil to overseas pedologists, and other terms introduced tenta­ moisture; tively as popular names were cumbersome for scientific use, Category III - (a) argillisation, or (b) the counter processes of particularly for the expression of intergrades. For these accumulation, removal, and mixing. reasons, in analysing the system of classification for more The classes of Category I cut across latitudinal and alti­ precise technical use, certain words were perforce coined. tudinal climatic zones while those of Category II lie within The technical terms, however, do not replace ~he popular them. Those of Category III are the principal classes, many names for other than technical purposes, since pedology of which are comparable with great soil groups of other needs a popular terminology suited to local needs. classifications. Names of the classes are derived for the most The New Zealand genetic classification is an attempt to part from the names of the basal forms, but a few are classify the soil as a dynamic system as it occurs in its derived from processes of accumulation or removal. Those environment. To obtain appropriate criteria for classification, in Category I end in -iform, those in Category II in -ous, the soil is considered as a system consisting of three inter­ and those in Category III in -ic. Concise technical names dependent parts (Taylor, 1949, pp. 111- 2) - the wasting, for classes are coined at these levels only. organic, and drift regimes. The wasting regime includes the processes of both physical The lower categories are subdivided according to processes and chemical weathering, together with the associated con­ and properties of genetic significance that modify the prin­ centration of chemical elements in various horizons and loss cipal classes as follows: (IV), kind and degree of illuviation, of elements by way of the drainage waters. The organic gleying, accumulation, etc.; (V), state of enleaching; (VI), regime - the impact of life on the soil - is the medium by parent material; and (VII), texture and other properties,, which intrinsic energy is replaced in the soil system and keeps mainly of the topsoil. Names of the classes in these categories it operating. It includes the addition to the soil system of are descriptive and are derived by modifying the name of the organic matter (with its supplies of carbon, nitrogen, and principal class by the appropriate adjectives or adjectival mineral elements, its power to retain cations and anions, phrases. and its effects on aggregation, on soil moisture and on soil The classification of the main soils is necessarily considered air), the organic cycling process by which living organisms independently of intergrades, the names of which may be take up chemical elements from the soil and return them derived at any level by compounding class names. to surface horizons, and the conditioning of leaching, illimeri­ sation, and argillisation by modifying the chemical and energy balance. The drift regime embraces the mechanical Category I disturbance of the soil system by inorganic agencies. It The first category of the soil classification is built upon includes the mechanical processes of erosion (movements 11 distinctive basal forms of the soil body which were 157 recognised in the early stages of soil surveys. The names tures. This basal form is exceedingly common and, owing to of the soil classes are set out below: the effect of modifying processes, gives rise to many sequences. CATEGORY I Podiform - (podzol) soils also occur characteristically in humid" areas. They have prominent 0 2 and ash-grey struc­ tureless silica-rich A2 horizons, and commonly but not Technical Names I Common Names alwars have humus and iron illuvial horizons. Owing to the· transient nature of the 0 2 horizon after clearing of forest, Sitiform . . Brown-grey the A2 horizon is the main differentiating characteristic. Palliform . . Yellow-grey Spadiform (red-brown) soils have red to brown soil Fulviform . . Yellow-brown bodies, typically without spectacular differentiation of Characterised by developed Podiform . . Podzols horizons Spadiform Red-brown horizons and with innate blocky and granular structures that Latiform . . "Ironstone" persist even when ordinary aggregates are crumbled to finer Nigriform . . Rendzina-like particles. They contain more sesquioxide colloids than do Soloniform . . Solonetzic Madentiform . . Gley fulviform soils, hence the stability of their structures. They Characterised by lack of de­ Organiform Organic are commonly formed from basic igneous rocks, or from veloped horizons Skeliform . . Skeletal (including sediments derived from these rocks. recent) Latiform ("ironstone") soils have a sheet-like morpho­ logy due to the arrangement of sesquioxides in distinct layers that are commonly concretionary. Their sand frac­ Sitiform (brown-grey) soils are formed in semi-arid areas. tions are characterised by secondary minerals. Owing to Their topsoils are brownish grey with platy structure, and their high content of sesquioxides, they have the brown to red the subsoils are brown. There is little obvious development colours of the spadiform soils and for the most part are ex­ in the profile, other than a thin topsoil and a marked clay ceedingly friable. illuvial horizon which in most places is a stronger brown Nigriform (rendzina-like) soils have deep non-peaty top­ colour than the horizons above. Soluble salts are present in soils, and have little or no B horizon. Generally they have well small amounts, and in many profiles there is a band of developed structure. They are commonly derived from calcium carbonate deposited below the clay illuvial horizon. limestones or other rocks rich in bases. Owing to the small area with a semi-arid climate, these soils Soloniform (solonetzic) soils are poorly represented in are not widely represented in New Zealand. New Zealand. They occur in semi-arid areas in low­ Palliform (yellow-grey) soils are formed characteristically lying or other spots flushed with soluble salts. They have in subhumid areas. They have well developed A1 horizons, friabie greyish topsoils and hard dark columnar structures, grey to very dark brownish grey in colour, with weak struc­ with diffuse humus in the subsoils. Although their topsoils ture. They have · a fragipan or .genetically similar massive may be low in soluble salts, they have alkali subsoils with horizon, in most places at depths below 10- 24 in. and com­ a high salt content. The lower parts of their subsoils in many monly yellowish in colour, with a gammate or reticulate places are lighter in colour and contain calcium carbonate. pattern of grey veins. The common name of yellow-grey Madentiform (gley) soils have predominantly gleyed earth was derived from the general yellowish grey appear­ horizons associated with high ground water,* while organi­ ance of the soil exposed in road cuts and similar excavations. form (organic) soils have bodies dominantly composed of organic matter. Skeliform (skeletal) soils show little or no Fulviform (yellow-brown) soils occur characteristically in profile development and include a wide range of weakly the humid areas. Typically they are well drained soils without developed mineral soils. spectacular differentiation of horizons, although many have illuvial horizons commonly of clay. They have yellow to *Where a high water-table is not present, soils which are dominantly gleyed but cannot be identified as gleyed modifications of other brown subsoils that for the most part have blocklike struc- forms, may be considered as pseudomadentiform. · 158 159 Category II In the second category, the main energy status of the soil as indicated approximately by latitudinal and altitudinal zones and by soil moisture is used to subdivide the basal forms. Thus, at this level the basal form and main energy status are combined to express the soil as a dynamic system. The latitudinal zones are indicated by prefixes as follows: per- (tropic), ad- (subtropic), pro- (temperate), de- (sub­ antarctic), and e- (antarctic). Corresponding altitudinal zones are indicated by the addition of el- (signifying elevated) to the prefix. Thus the prefixes elde- and ele- refer to soils of I the subalpine and alpine zones respectively, which have many features in common with the corresponding soils of the subantarctic and antarctic. Similarly, elpro- refers to elevated soils of the subtropics or tropics which correspond to lowland soils of the temperate zone, and elad- to elevated soils of the tropics which correspond to lowland subtropic soils. The subalpine commonly covers the ,scrub forest, scrub, and herbfield to. the level indicated by the upper limit of continuous plant cover over the easier more stable slopes; the alpine covers areas at higher altitudes where the plant cover is discontinuous or absent. The lower limit of the subalpine is about 3,000 ft in the south and 4-5,000 ft in the north, and the upper limit is about 5- 6,000 ft in the south and 6-7,000 ft in the north ( fig. 17), but varies considerably with local conditions. The boundaries of zones are actually determined by reference to the dominant soils and not merely by reference to such measurements as latitude and altitude.* Most of the basal forms of Category I reflect in a general way the kinds of soil processes that are governed in large measure by effective moisture. Skeliform, however, does not indicate the effective moisture, and consequently phasic subdivisions based on soil-moisture classes (p. 45 need to be introduced here. Phasic subdivisions are also used, either here or at the level of Category III, for other classes that cover too wide a range of moisture to express the soil system adequately.

*It is often expedient to recognise upper and lower phases of soils a.1e pv ade::, in the altitudinal zones, for example, the upper (upper ele-) and lower ('lower ele-) alpine zones. The soils of the basement zones (those which do not bear the prefix el-) are also commonly subdivided into upland and lowland phases. Where necessary, ele­ asea llO)S vated soils may be phased by referring to the latitudinal zones in which they occur; for example, a subalpine soil in the tropics (lJ coo,) .lH!:>l:IH may be classed as ".tropic elde-". 160 161 To simplify names as much as possible, the prefix pro­ The grade of argillisation is applied in a comparative may be omitted from the nam~s of classes that are well way. The grade attained by the more stable soils that date represented in the temperate zone - that is, of all except from the last zone-wide, climatic, soil-destroying catastrophe the spadiform and latifom1 soils, from the names of which is taken as the standard for the particular moisture region the prefix ad- may be omitted since they are better repre­ of the zone. If moisture is adequate, the standard is weak sented in the subtropics. This convention is applied also in the subantarctic zone, moderate in the temperate zone, to the names of soils in the corresponding altitudinal zones. and strong in the subtropic and tropic zones. Where soils Names of classes in Category II are indicated by the suffix conform with the standard for a region they are con­ -ous as in the following examples: formably argillised, where markedly less weathered than the standard they are subargillised, and where they are CATEGORY II considerably more weathered they are surargillised. Category I Many subargillised soils arise from local disturbances later Technical Names I Common Names in time than the last zone-wide catastrophe; others occur in places where the rate of erosion or accumulation is Fulviform soils . . Perfulvous . . Tropic yellow-brown Affulvous• Subtropic or northern yellow-brown sufficiently rapid to rejuvenate the soil continuously. (Pro-) Fulvous . . Temperate or southern yellow-brown Surargillised soils have soil bodies that are more strongly El(pro-)fulvous . . (Elevated yellow-brown, corresponding to temperate, in tropics and subtropics) weathered than the conformably argillised one's because Dcfulvous . • Subantarctic yellow-brown Eldefulvous . . Subalpine or high country yellow-brown they antedate them. Strictly, "surargillised" should be applied only where the soil body (the complete profile) ( Perskelous .. Tropic skeletal t; I Adskelous .. Subtropic skeletal is retained continuously from a former weathering cycle Skeliform soils .. ·o ~ (Pro-) Skelous Temperate skeletal to the present day. If an erosion interval has intervened, :a lDeskelous .. Subantarctic skeletal Eldeskelous .. Subalpine skeletal the remains of the old soil body are more correctly regarded as merely the surargillised parent material of the •In prefixing "ad", the common rule of assimilation is applied. present one. Since it is often impossible to tell to what extent erosion has occurred, and since the horizons even of incomplete old soil bodies can strongly affect the develop­ Category m ment of present-day soils, a convention is adopted. A soil In the third category, the classes of Category II that is said to be surargillised, at least in part, if a recognisable contain mineral soils with developed horizons are subdivided depth of the old soil body remains; if, however, the material according to the state of weathering of the soil body as of the old soil body has been transported from its original indicated by the kind and grade of argillisation (pp. 24- 27). site, continuity is broken and the new soil formed upon The other classes ( organiform and skeliform) are sub­ this material is regarded as being derived from a new divided according to the processes of accumulation, removal, sedimentary deposit of pre-argillised materials. Subargillised and mixing, which tend to oppose the progressive develop­ soils naturally tend to have soil bodies similar in many ment of a weathered soil body and the formation of horizons. respects to those of conformable soils of cooler zones The kinds of argillisation are indicated by the dominant where argillisation is weak, and surargillised soils to those residual clays, the three broad groups of which (Appendix of warmer zones where argillisation is strong. 7, p. 192) are used as criteria. Names of classes with In class names, the grade of argillisation, where not characteristic properties dominated by amorphous clays and conformable with that of the zonal region, is indicated by crystalline oxide clays are distinguished from those with adding the prefixes sub- (subargillised) and sur- (sar­ crystalline layer silicate clays by the prefixes amo- and oxi­ argillised). These divisions are applied in the broadest respectively. To simplify the names, the prefix oxi- is possible manner, but it is sometimes necessary to split the omitted from the latiform soils as, ·in these, crystalline subargillised soils into the younger and the older subargillised oxides are usually dominant. Contractions are also used for soils in the tropic and subtropic zones, because of the wide some other common soils ( see p. 164) . range of weathering they embrace. 162 163 ]' .0 (U Names of classes in Category III are indicated by the ]' ::a'o' ::a'o' (I) E ~ (U (U suffix -ic. In forming them the prefixes denoting grade "O !6 ro (I) (I)§ § (I) § of argillisation (sub- and sur-) are placed before the zonal ...... 'a0 ... 0 eu ~c8 'a 'a~ c8 prefix of Category II and those denoting kind of argillisation (!)-~bl) C: "O~ c:~0 ~o ~o~ ~§ (amo; and oxi-) are placed after it. For some common 0 '8 ~§ o3 O~O~o 0~ -~ ~ :::~ ~ ::: ~ ~ ~~ soils, appropriate contractions are used as shown in the examples on the opposite page. :3 ~ ·5o "'(I) Processes that govern the accumulation of organic matter "O "O C: "'(I) -~ and determine in part its composition are used to subdivide < "' 0 ~ "'::s the organiform classes. Thus the (pro-) organic soils are i:: ] 0 "'::s "'::s (I) ro ..c:: :.:::~ 0 0 C: divided into the lodic soils (blanket peats) and the platic .s "'... e, ·;;; ..c:: (I) 0 ... e, soils (concave basin peats). Lodic accumulations are (I) e~ 6 ;,-. 0 e 0 ot; climatic or ombrogenous. They form under suitable con­ ~ j < ~ e St ~ ~ < - -~ :g"' tribution and occur where normal decomposition in the zone =: .Bo(!)= "' is slowed down owing to local conditions of topography, 8 ~ (I) "' "';,-. ~"' ~;,-. E ro (I) ... ro soil, and high ground water. For the most part, they ~ "' ro C: ·i 0 u 6 (I) ..9 ::s "'6 occur in humid regions in basins where the ground water ~~ 0. ro... ro C: C: ... C: ..9 is close to the surface, but they are not confined to such z (I) "3 ~ ~ ~ ~ C: C: 0 0~ 0 0 C: regions. They include the small patches that form near ...... (U ... 0 .0 ... e ~ 6 ~ .0 (I) .0 bl) 0... springs and seepages. In general they contain more mineral ~ ·~ ~ ~ C: .0 e 0 (I) 0 matter than the lodic accumulations. The soils of raised 0 ..9 ~· ..9 ~ ~ 0 --6 u ~~ ;,-. G) ... bogs which are in part ombrogenous and in part soligenous 1 ;,-. ;,-. .0 e (I) (I) (I) or topogenous are regarded as intergrades (lodi-platic or ...... E (.) -~ ro 0. ~... ro c~ "' ro ... ·a 0 plati-lodic soils). C1) ~ ~~ ~ C1) 0 ... 0. 0. 0. ... 0. 0. ... 15 Processes that govern the accumulation, removal, and E E 15 ::s (I) 55 ~ 5 (I) ::s Cl) mixing of mineral matter are employed to subdivide the (:,-. r-' r-- r-' r-' Cl) ~ skeliform classes. Thus the (pro-) skelous soils are divided .$.!a ~ into luvic soils (recent soils rejuvenating by water-borne ·,n5 ~ ·s ~ accumulation), volic soils ( recent soils rejuvenating by air­ "'"' ·s ~ "'"' ]*"' ~ ~ ·s u=-= ·- C1) "' ·s fl) ·- 0 borne accumulation), clinic soils (skeletal soils rejuvenating c: E ·s ·s (.) fl) "O"' ro "' ->-~-~ fl) ·;; by movement down slope), and regic and lithic soils -5 "O-~ 8-~ -~ .Z"3 -; "O-~ ro ro -r::, ~z > .0 't:: -~ .0 ro .o ro (regosols and lithosols which are not rejuvenating).* Luvic I "3 ::s ::s ::s 0. 6 ::s >< and volic soils are properly recognised by their internal ~ Cl) Cl) Cl) Cl) < Cl) 0 I < evidence of accumulation, their upper· layers being younger ·s~ ·s~ -~ fl) *For some purposes it is convenient to refer. to subdivisions of soil "' fl) - "'::s ::s body form by using terms based on names in Category III. When -i:' 0 0 0 > "O this is done, the suffix -oid is used in order to prevent confusion bl) "3 ro with names that are properly part of the classification. Thus ~ l,l,c IA I u ,-;-- I ~ "luvoid" refers to soils with soil bodies similar to those of the ...0 -6 I luvic soils, for example the alluvic, ]uvic, and deluvic soils. Similarly, < I "affulvoid" can be used to refer to the perfulvic, affulvic, and surfulvic soils. 164 165 than the lower ones. However, where the soil is developed, intergrades to fulvic soils - and are not solely clinic soils; as on a flood plain, on a single thick accumula­ similarly the luvic and volic soils are generally much less tion, it is conventionally retained in the luvic soils (although extensive than their associated intergrades, since accumula­ it is strictly regic rather than luvic) on the grounds that tion over wide areas is rarely so fast that it prevents the it is in a strongly accumulating environment. Other than partial expression of basal forms other than skeliform. melanisation of the topsoil, clinic soils show little or no profile differentiation, because they are continually being Pha,sic Subdivisions Based on Soil Moisture rejuvenated by removal, accumulation, and mixing con­ As described under Category II (p. 160), phasic sub­ sequent on colluvial movement down slope. For specially divisions based on the soil-moisture classes are applied at detailed studies, they may be divided into phases according the level of Category III as needed. to the dominant process - regressive and accumulative clinic In some arrangements of the soil classification, notably soils; and where necessary, this principle may be used . to on the legends of some soil maps, the approximate moisture subdivide other classes. The regic and lithic soils . have class for particular soils has been indicated indirectly by little or no profile development because insufficient time noting their association with a soil that has a characteristic has elapsed since the inception of soil formation, rather moisture regime. Thus rendzina-like soils "associated with than because of soil-rejuvenating processes. The regic soils yellow-brown earths", and those "associated with yellow­ are formed on drifts of fine texture. Where soil formation grey earths" are indicated as falling into different moisture is rapid, as in warm, humid regions, they are short-lived. classes. The association of one soil with another, for this The lithic soils occur on hard, massive rocks and coarse or any other reason, can be conveniently expressed with an drifts ( such as lava flows and moraines), which are so adjective formed by prefixing "co-" to the technical name resistant to change that they persist for a long time without of the soil class appropriate for the purpose in hand, for the formation of evident soil horizons. example, co-fulvic nigric soils and co-pallic nigric soils. In subdividing the eleskelous and eskelous soils, two In applying the soil-moisture classes it is important . to additional classes are needed, the gelic and frigic* soils, appreciate that they express soil moisture only and are not which refer to soils stirred by frost action. Gelic soils are a substitute for the more detailed characterisation of the found in regions such as the alpine, where the surface is soil body as required in the lower categories of the classi­ bare of insulating vegetation. Under these conditions the fication. For example, the Okarito soil of Westland is surface soil is lifted by fr<1St and, following the thaw, its correctly classed as a hydrous podic soil at the level of finer fractions tend to be blown away, leaving a stony Category III but, however strong the implication, it is not surface layer or "pavement".· Frigic soils, which occur in definitely indicated as a gley podzol until it has been classed antarctic regions when~ this and allied processes are strong, in Category IV. ·have subsurface permafrost. In some small areas in the temperate regions of New Naming of lntergrades in Category Ill Zealand, soils are found with little or no profile develop­ The names of intergrades at the level of Category III are ment due to continuous mixing by organisms. They are derived by compounding the class names. The stem of the classed as bioturbic soils. They are best illustrated in the subordinate name, with the connecting vowel "i" is linked nesting areas of burrowing sea birds where, besides being by a hyphen to the full name of the class that the intergrade thoroughly stirred, they are enriched by droppings. · most closely resembles. Thus, in the progression from a In the New Zeal~d sector ( outside the antarctic and clinic to a fulvic soil, a fulvi-clinic soil is one which shows alpine regions) skelifoi:m soils are very much less extensive some fulvic characters but has not the structural B horizon . than their intergrades to associated soils. In humid temperate associated with fulvic soils, and a clini-fulvic soil is one regions, for example, soils on steep slopes are mostly that shows the characters of a fulvic soil, although modified by slope conditions. In a similar way, a podi-fulvic soil is <•since the elegelic and efrigic soils are very limited in their weakly podzolised, and a fulvi-podic soil is moderately geographic range the zonal prefixes may be omitted where the meaning is clear. podzolised but retains some fulvic characters, especially in 166 167 the subsoil. For conciseness, it is usually unnecessary to Category V repeat zonal prefixes; thus a fulvi-alluvic soil is an intergrade In the fifth category, subdivision is based on the state between the northern rapidly accumulating recent soils from of enl.eaching whicfr isi the balance of the incoming and alluvium and the northern yellow-brown earths. outgoing mineral ions in the active fraction of the soil Where it is desired to indicate that the soil is an abnormal body: Where the effects of the drift regime are small, the intergrade resulting from the burying of part or the whole state of enleaching in a general way expresses the state of an old soil, the connecting vowel "o" is used in place of near equilibrium between the rate of weathering, the of "i". Thus a composite soil, the upper part of which is rate of leaching, and the cycling of mineral elements by formed in fresh alluvium and the lower part in concave the organic regime. It is not identical with (but is basin peat, is named a luvo-platic soil to distinguish it from approximately indicated by) the degree of salinity (p. 112) the luvi-platic soil which is a normal intergrade formed and the percentage base saturation of the soil, which are from peaty loams, peaty clays, or other admixtures of the criteria used for classification. It may be applied to the peat and alluvium. Similarly a fulvo-surfulvic soil is a soil as a whole or to individual horizons~ but unless otherwise composite soil, the upper part of which may be from specified refers to the average for the solum. The classes soliflual or glacial material, while the lower part is old for state of enleaching other than saline (and their approxi­ surweathered soil. mate correlations with percentage base saturation) are: weakly (over 50), moderately (30-50), and strongly (less Category IV than 30) enleached; where needed, the subclasses very The fourth category is subdivided into broad class\!s based weakly . (70-100), and very strongly (0-15) are also on the salient remaining morphological differences, which separated. are interpreted in terms of the kind and degree of the· processes that produced them. Such processes fall into two Category VI groups: those that lead to, and those that tend to retard, The sixth category is divided according to the remaining the development of ordinary soil horizons. The effects of combinations of soil properties due directly or indirectly to the first group of processes include the kind and degree difier~nces. in parent materials. The. classes are named by of illuvial development in the soil, such as arises from referrmg directly to the parent matenal, as in the examples illimerisation (p. 110), podzolisation, and in a few soils "from strongly argillised greywacke", "from comminuted desalinisation; also included is the degree of gleying of schist", and "from weakly decomposed fem peat" (i.e., soil. horizo.as (p. 81), which may be referred to individual D4, see p. 125). horizons or to the soil ·as a whole, but unless otherwise stated refers to the B horizon where it is most common. Category VII Illuvial horizons, for example, those in podzolised soils, are referred to as "humus illuvial" or "iron illuvial", etc.; The final category of the classification is subdivided or, as in the case of related formations, they are referred according to texture, the organic profile, and to modifications directly to the formation itself, as "with concretions" or (including ·those due to man) that affect the soil profile "with fragipan" (pp. 104, 109). Separation of the main partially but not strongly enough to be expressed in higher classes at this level is based on striking differences in the categories. degree of expression of the criteria used. Hence, clay Commonly, the texture of the topsoil is given, but it illuvial, gleyed, and other terms, when used without quali­ may be supplemented as necessary by the texture of the fication, connote moderate or· strong degree. The effects subsoil, for example, "sand on clay". The organic profile of the second group of processes such as erosion and of ·many topsoils is subject to rapid modifications following accumulation and those giving rise to mixing, all of which modifications of vegetative cover, whether natural or man­ tend to retard the development of soil horizons, are used induced. Consequently, as a differentiating character of the in a similar way, particularly for the skeliform soils and current soil system, it is introduced into the classification their intergrades, as in "weakly accumulative luvic soils". at this low level, its more stable eflects having already 168 169 been covered in the higher categories. The nomenclature is taken from the classification of organic profiles (seep. 115) but, in the absence of detailed information, the differences in organic profiles have commonly been indicated in a broad way by reference to the vegetation that has produced them, as in "scrub melanised" and "tussock melanised". Where modifications due to man or other agents change both topsoil and subsoil sufficiently, they are classified systematically at appropriate higher levels of the classification or as intergrades. Where, however, they affect only the topsoil, or partially affect conditions in other horizons, as in most artificially drained soils, they are best expressed at the low level of Category VII.

GENETIC NAMES Genetic names for soils emerge from the criteria applied to them under the various categories. To give each criterion its appropriate connotation, terms derived from Categories III- V and also those from VI- VII are reversed in order; that is, those from Category V are given first and followed by those from IV and III and, where applicable, VII and VI. The complete names are generally long, but simpler names are derived by omitting characteristics that are weakly expressed and terms that are subordinate or redundant. Usually for example, the state of enleaching need not be given for podic or latic soils where it is almost always strong; "fragipan" need not be included where it is indicated together with its form by the term "gammate"; and clay illuvial, gleyed, or other terms of Category IV which imply well expressed characters, need not be qualified (p. 168). If table 6 be taken as an approximate analysis to Category VI of five common soil types, the simple genetic names are: Okaihau gravelly friable clay: concretionary Jatic soil from strongly argillised basalt Taupo sandy silt: moderately enleached subalvic soil from rhyolite pumice Taita clay loam: strongly enleached clay illuvial sur­ fulvic soil from strongly argillised greywacke Timaru silt loam: moderately enleached gammate pallic soil from moderately argillised loess Conroy gravelly sandy loam: weakly enleached clay illuvial sitic soil from comminuted schist :~ For many purposes the names are further simplified by

THE CLASSIFICATION ZONALLY ARRANGED In the early years of the soil survey, the multiplicity of units and the many confusing ideas about their classification led to attempts to arrange the soils zonally in an endeavour to get some main threads of order. The zonal arrangement was based on the New Zealand modification of Marbut's normal site (p. 28), and in effect represented an attempt to classify the soils keeping certain factors constant. The soils on such normal sites were called zonal since they occurred in a dear zonal pattern. In this way, differ­ ences due to various miscellaneous factors were set aside, and differences due to climate and vegetation were allowed to emerge. Other soils were regarded as dominantly in­ trazonal or azonal, or as intergrades. This arrangement has proved most valuable for demon­ strating and helping to understand soil relationships, and is stil1 a useful method of presentation. It is not, however, 173 a necessary part of the classification; it is no more than a special arrangement of the classes of Category III. The Appendices classification may be zonally arranged in two main ways­ first, by arranging the soil classes in zonal, intrazonal, and APPENDIX 1-Equivalent Measurements and azonal groups; and secondly, by arranging zonal soils and Abbreviations in Common Use their associated intrazonal soils in groups according to the various zones. Length The main soils of the legend of the soil map in A Descrip­ 1 inch = 2 · 54 centimetres 1 mile = 1 · 6 kilometres tive Atlas of New Zealand (Taylor and Pohlen, 1959) are 1 centimetre = 0 · 394 inch given in table 7 together with technical equivalents of the 1 metre = 39 · 37 inches common soil names. 1 kilometre = 0 · 6214 miles

Area 1 acre = 0·4047 hectares 1 square mile = 2 · 5899 square kilometres 1 hectare = 2 · 47 acres 1 square kilometre = 0 · 3861 square mile

Volume 1 cubic inch = 16 · 387 cubic centimetres 1 cubic metre = 1 · 308 cubic yards 1 litre = 0 · 8799 quarts 1 gallon = 4· 546 litres = 1 · 2009 U.S. gallons

Weight 1 pound = 0 · 45359 kilograms 1 kilogram = 2 · 2046 pounds 1 gallon of water at 62°F (16·7°c) weighs 10 pounds 1 cubic foot of water at 60°F weighs 62 · 37 pounds

Angles of Slope and Per Cent Grades Degrees Per Cent Degrees Per Cent 2 3·5 15 26·8 4 7·0 20 36·4 6 10·5 25 46·6 8 14· 1 30 57·7 10 17·6 40 84·0

Equivalent Map Scales (by C.T.T. Webb) British Units Fractional Scale (R.F.)* 32 miles to inch 1 :2,027,520 16 miles to 1 inch 1: 1,013,760 4 miles to 1 inch 1 :253,440 2 miles to 1 inch 1: 126,720 1 mile to 1 inch 1 :63,360 40 chains to 1 inch 1: 31,680 20 chains to 1 inch 1: 15,840 10 chains to 1 inch 1:7,920 5 chains to 1 inch 1:3,960 *R.F. = representative fraction. 174 175 fractional Scale (R.F.) British Units APPENDIX 2 - Main Map Series in New Zealand with the 1 : 2,000,000 31 · 57 miles to 1 inch National Grid 1: 1,000,000 15 · 78 miles to 1 inch 1 :250,000 3 · 95 miles to 1 inch By C. C. T. Webb, Department of Scientific and Industrial 1: 100,000 1 · 58 miles to · 1 inch 1 :25,000 0 · 395 miles to 1 inch Research. or 31 · 56 chains to 1 inch Maps showing the National Grid and published in New Zealand by the Department of Lands and Survey are: Textural Symbols Series No. Scale Kind Symbols commonly used in forming abbreviations for soil textural N.Z.M.S. 1 1 :63,360 Topographic names and in qualifying them are: N.Z.M.S. 2 1 :25,000 Topographic s sand or sandy It light N.Z.M.S. 3 1: 15,840 Photo mosaic si silt or si'lty h heavy N.Z.M.S. 18 1 :250,000 Topographic cy clay gr gravel or gravelly N.Z.M.S. 86 1: 15,840 Topographic (Rotorua- 1 loam or loamy st stony Taupo only) p peat or peaty b bouldery N.Z.M.S. 177 (parallel 1 :63,360 Cadastral (shows grid cuts c coarse r rocky with N.Z.M.S. 1) in margin) m .. ... medium fr friable Miscellaneous Varying scales National Parks etc. f ...... fine sh ...... shallow d deep A comprehensive list of maps published by the Department of Lands and Survey is given in the Department's Catalogue of Maps, Thus clay is abbreviated as cy, friable clay as fr cy, light silt amendments to which are published quarterly and· circulated to loam as lt sil, gravelly peaty loam as gr pl, clay loam as cyl, fine holders of copies of the Catalogue. sandy loam as fsl, and so on. The early or provisional editions of the N.Z.M.S. 1 series have a grid that is not in terms of the datum for the National Grid determined in 1949 but is based on the meridional circuit. Con­ sequently in these editions discrepancies of several hundred yards may occur between the "provisional grid" and the National Grid for the same area.

176 177 APPENDIX 3 - Use of the Hand Lens and Pocket Magnet colourless fungi, or microfauna such as protozoa. Generally the in Soil Studies grazing of mesofauna, for example, mites and Collembola, produces rough-walled cavities, but soft-bodied mesofauna for example, Nematodes and Enchytracids which generally accompany decom­ Hand Lens position under moister conditions, are associated also with the smooth... type of cavity. lly J. D. Raeside and Beryl C. Barratt, Soil Bureau. Fauna and Fauna/ Remains: When present, chitinous residues With the unaided eye, the pedologist can make only a composite should be · noted, as they indicate the scarcity or absence of micro­ appraisal of the soil horizons. Properties that pertain to the organisms capable of breaking down this kind of organic substance. individual aggregates or the constituent mineral grains cannot be These residues also aid in the identification of some of the active fully resolved. A hand lens is thus an indispensible item of field fauna. In places, the living fauna may also be found grazing in a equipment. Generally, detailed microscopic study of the soil in the cavity formed in plant tissues or occupying cavities in the mineral field, beyond the resources of a hand lens, is neither practical nor soil. In the latter case, light-coloured species are more easily necessary, except for special purposes as, for example, the study of detected against the darker soil background. some biological factors in the soil in situ. The general nature of Fauna/ Excrement: Research is still in progress on the variety of grain coatings and the most prominent features of the soil fabric form and the content of faecal pellets and casts produced by the can be conveniently determined in the field, but detailed microscopic soil fauna but it has been found that a given species can produce study of the soil is best conducted in the laboratory. more than' one kind of dropping according to the materials ingested. The most suitable hand lens is a two- or three-component lens However for convenience in description, a small number of pellet with a maximum inagnification of 10 or 12 diameters. This permits types ar~ recognised according to the soil fauna with which they several different degrees of magnification. Observations that can seem to be most frequently associated. They are: conveniently be made with such a lens are considered for convenience Mite type- Usually formed by mites, Collembola, and Diptera u~der three main headings: organic materials; soil microstructure, larvae. Small (generally less than O· 1 mm in diameter), discrete, m1croporosity, and special formations; and parent materials and spherical or oval, humified, rust to dark brown, lacking mineral soil skeleton. grains. Enehytraeid type - Associated particularly with enchytraeid Organic Materials populations. Small (0· 15-0· 2 mm), discrete, subspherical, Concentrations of organic matter can occur in surface humus rugose, generally well humified, brown, but containing varying layers or where roots are concentrated, as on the surfaces of peds amounts of mineral grains and clay owing to variation in species and stones, in cavities of various origins, and overlying impenetrable behaviour. soil horizons or underlying layers such as the unweathered parent Arthropod type - Also formed by small surface-feeding earth­ rock. They may be little decomposed and of recognisable origin, worms. Visible to the naked eye_ ( 1 · 0-3 mm long), discrete, they may be finely comminuted, or they may be mechanically or well . humified, dark brow.n, containing mineral grains but low intimately incorporated with the mineral soil. in clay. Plant Remains: Components of recognisable origin are identified Worm casts -largely due to surface-casting earthworms. Well as to plant species and organ, and their colour is described in simple humified, generally brown or greyish brown, containing mineral colour terms or, in critical cases, the Munsell notation. The nature grains and clay, spongy or coarse rugose cast granular structure and degree of their decomposition is described according to the kind ( 5-10 mm in diameter) . of tissue attacked, the organisms associated with it, and the quantity Distribution of Rootlets: Rootlets may be evenly distributed and quality of discoloration and disintegration. through each horizon or they may follow preferential paths; in Rust-brown discoloration, particularly in fibrous leaves, is usually some soils of heavy texture rootlets follow fissures between associated with very feeble general decomposition, and it is aggregates. There is no suitable field test for living or dead roots. detectable in the herbage before leaf fall. It probably induces decay­ In some soils healthy roots preponderate, whereas in other soils resistant properties and it has been causally associated with the part there is a preponderance of roots that are discoloured, distorted, or played by vegetation in the differentiation of mulloid and moroid indented by the relatively weak agencies of decomposition which profiles. Brown and brownish-yellow stains, on the other hand, show are unable to keep pace with the supply of dead root material and that decay is occurring even when externally the structure appears cannot decompose it completely under the unfavourable soil con­ intact. When present, fungal mycelia, generally brown or white but ditions prevailing. sometimes of other colours, are noted, together with the main tissue attacked. External evidence of structural breakdown is given by com­ Soil Microstructure, Microporosity, and Special Formations pression or other distortion, by translucence or transparency, and by Observations on the mineral soil with the aid of the hand Jens the breakdown of tissues into smooth, tapering hollows. The often are conveniently considered under the headings of . microstructure, invisible agents of this kind of decomposition may be bacteria, microporosity, colloidal coatings, and nodular and crystal growths. 178 179 Microstructure: No satisfactory nomenclature for soil micro­ structure has yet been devised, but where possible it is named in The presence of colloidal coatings on the grains of he mineral the same terms as macrostructure. The size smoothness and skeleton is an impcrtant soil character. In some of the yellow-brown angularity of the peds are noted, and also thei; lustre, using _such earths on the margin of the Catlins district, for example, the terms . as _earthy, saccharoidal, vitreous, and waxy, as this reflects the horizon under the humus topsoil is brown and the mineral grains organ_isatipetrology. The classes, with their International example soils formed from the ~reywackes of <;anterbury a~ t e Scale equivalents (p. 83) for comparison, are: schists of Otago, little may b_e gamed by att~mptmg a separation. In Very -coarse-1-2 mm soils derived from more basic parent matenals, however, these two l fractions may be easily differentiated. . Coarse -0· 5-1 mm ~coarse sand (0 · 2-2 mm) Medium -0·25-0· 5 mm The proportion of magnetite, on the other hand, ca~ be _obtamed J with reasonable accuracy (within the limtis of. field eshmat_10n) and Fine -0· 1-0·25 mm }fine sand (0·02-0·2mm) Very fine -less than O· 1 mm there is little likelihood of the magnetite fract_1on overlappm~ other less magnetic fractions. In many cases the yield of m_agn~hte can be used as a direct measure of the degree of contamm~hon C?f a parent material derived from a sedimentary rock by _matena~ derived from basic sources; it is therefore not only an easily obtamed but Pocket Magnet also a very useful field character. By J. D. Raeside. A small pocket magnet can be used to supplement the informa­ tion obtained from the use of the hand lens in studying the nature of the mineral skeleton of the soil and getting some information about its provenance. The most convenient magnet is a small pot magnet of the type manufactured by Eclipse. The magnet is made of Alcomax steel in the shape of a cylinder and (together with keeper) is ~16 in. in length and in diameter. This magnet is sufficiently powerful to separate, not only magnetite of high magnetic susceptibility, but also oxide minerals of lower susceptibility and non-magnetic minerals with inclusions of magnetite or ferromagnetic oxides. The separation can be made with a small piece of paper over the end of the magnet or with the bare poles. A convenient procedure is to make a preliminary or first separa­ tion with the magnet-pole surface approximately 1 cm above the powdered soil which should be as nearly dry as possible. A second separation is then made with the magnet about O· 5 cm above the 182 183 APPENDIX 4 - Parent Rocks of New Zealand Soils 10. Quartzo-feldspathic mudstones (undifferentiated), including sandy mudstones: By J. J. Reed, New Zealand Geological Survey. 10a. Normal 10b. Highly siliceous The broad classification of parent rocks of New Zealand soils set 10c. Highly micaceous out below is intended to serve as a guide in forming soil suites and 10d. Calcareous in grouping and naming the various rock types in connection with 10e. Bentonitic soil descriptions. In classifying limestones and other calcareous 1Of. Carbonaceous rocks which on weathering lose most of their mass by solution 11. Limestones (undifferentiated): particular attention is paid to the impurities since these give rise t~ 1 la. Mainly soft or shelly limestones the residual clays which impart their characteristics to the soil. 11 b. Crystalline limestones 1 lc. Marbles Plutonic and Volcanic Rocks and Gneisses Unconsolidated Cover Beds 1. Granites (undifferentiated), including diorites, amphibolites, etc.: 12. Volcanic ashes (undifferentiated): la. Potassic 12a. Coarse rhyolitic (Kaharoa, Taupo, Gisborne, Whanga- lb. Sodic mata) - related to 3b 2. Gneiss (undifferentiated) : 12b. Fine rhyolitic (Waihi, Tirau) - related to 3b 2a. Acidi~ 12c. Mixed rhyolitic-andesitic (Mairoa, Rotomahana) 2b. Basic 12d. Hornblende-andesitic (Hamilton) - related to 4a 3. Rhyolites and dacites (undifferentiated) : 12e. Hornblende-augite-andesitic (Egmont, Stratford, Burrell) 3a. Normal rhyolites and dacites - related to 4a 3b. Hypersthene-plagioclase rhyolites and ignimbrites 12f. Hypersthene-augite-andesitic (Tongariro, Ngauruhoe) - 4. Andesites and andesitic basalts (undifferentiated) : related to 4b 4a. Hornblende-andesites and andesitic basalts 12g. Olivine basaltic (Rangitoto, Tarawera) - related to 5 4b. Hypersthene-augite andesites 13. Loess (undifferentiated): 4c. Altered spilites, dolerites, etc. 13a. Quartzo-feldspathic ( derived from greywacke and 4d. Alkaline andesites and basalts argillite) 5. Olivine basalts 13b. Quartzo-feldspathic with · chlorite, epidote, and sericite 6. Ultramafites (undifferentiated), including gabbros, norites, and ( derived from schist) associated altered volcanics and sediments 14. Gravels with interstitial and covering silts, etc., of similar com- position, mainly alluvial (undifferentiated): 14a. Greywacke gravels 14b. Schist gravels Strongly lndurated and Metamorphosed Sedimentary Rocks 14c. Granitic and siliceous-greywacke gravels with minor 7. Greywa~kes and argillites (undifferentiated), including dioritic sem1sch1sts: 14d. Granitic, dioritic, and greywacke gravels, etc. 7a. Arkosic 15. Gravels with covering silts, of different compositions, mainly 7b. Arkosic - tuffaceous alluvial (undifferentiated) 7c. Arkosic - tuffaceous with vitric tuffs and zeolites (less 16. Windblown sands, mainly coastal (undifferentiated): indurated than 7b) 16a. Quartzose 7d Siliceous (quartzites, cherts, etc.) 16b. Quartzo-feldspathic 8. Quartzo-feldspathic schists (undifferentiated) derived from grey­ 16c. Ferromagnesian and magnetite-rich wacke and argillite 16d. Calcareous (shelJ beds, silty sands, etc.) 17. Silts and clays, mainly alluvial (undifferentiated): 17a. From acidic rocks 17b. From intermediate rocks Moderately to Weakly lndurated Sedimentary Rocks 17c. From basic and ultrabasic rocks (including Limestones and Marbles) 17d. From quartzo-feldspathic sediments 9. Quartzo-feldspathic sandstones and conglomerates (undiffer- 18. Peats (undifferentiated) entiated): 9a. Normal 9b. Highly siliceous 9c. Highly micaceous 9d. Glauconitic 9e. Calcareous 185 APPENDIX 5 - Recognition and Nomenclature of Deposits similar mineralogical characteristics. The lack of certainty of of Volcanic Ash recognition has made the compilation of isopach maps and even maps of distribution very difficult. In many cases not only is the By D. Kear, New Zealand Geological Survey. source of the ash unknown but the rock type of the parent volcano is also in doubt. New techniques may be required before Volcanic ash of Recent and upper Pleistocene age is widespread the older.. ash beds can be differentiated satisfactorily and before in the North Island of New Zealand. It occurs as primary deposits their distribution can be determined and explained. On the other of ash at the present ground surface, as rewashed material in river hand, it is possible that existing techniques will be adequate if and coastal terraces, as distinct beds within peat and alluvial these beds are subjected to the same detailed field work as the sequences, and even as a cover upon the "human occupation younger deposits have been in recent years. layers" · of the archaeologist. Over most of the central part of the North Island, it is the parent material of the soil, and in most other parts of the Island it contributes to the parent material in greater or less degree. Because of their wide distribution in New Zealand, volcanic ash beds are specially significant to the pedologist and the Quaternary geologist. When their main distinctive features have been identified, and especially after they have been datedJ ash beds form valuable marker horizons in sequences that in many places are far away from the source of the ash. Initial problems of identification and dating are often quite considerable, but practical techniques for field observation and subsequent description and nomenclature have evolved steadily through the publications of many workers. Volcanic ashes have been identified mainly by their macroscopic lithology, and recently they have been described from type localities in the manner adopted for other rock units. Isopach maps (showing the thickness of the ash) have become of fundamental importance in the study of ash beds; they indicate the likely position of the source, they enable variations in the lithology to be studied, they help to resolve differences of identification, and they form a basis for calculating the total volume of the shower material. Breaks in the ash sequence, typically indicated by fossil soil horizons, are useful in limiting the vertical extent of individual formations. Thus a formation becomes the total product of one or more eruptions which were intimately connected in time and space, and which can be assigned broadly to a period of volcanic activity in which there were no long breaks. The products of a single ash shower would rank as "members", and some workers have already made use of the fact that not all members need be named. Several formations may be considered as showing an essential unity, and may thus be styled as a "group" but, since it is exceptional for volcanic ash to be present in thick sequences to the exclusion of all other material, ash formations are usually recognised as part of groups of strata that include other rock types. This system of nomenclature works well for the younger ash beds, especially since their correlations and identifications can often be compared in the light of radiocarbon dates and mineralogical determinations. Recent unpublished work may also assist their correlations with floral and coastal aggradational sequences. The older ash beds, however, are not so amenable to the above techniques of recognition and nomenclature. Many are highly weathered, and in addition their identification is hampered by erosion. Mineralogical differences between some of them have been noted to a limited extent in the past, and additional work upon these lines may yield valuable results in the future. Such work, however, cannot differentiate between ash beds that have 186 187 APPENDIX 6 - Measurement of Soil Radioactivity, and Both field measurements of gamma activity and laboratory measure­ Measurement of Soil Moisture and Density by Neutron and ments of the beta radiation were made. For the laborat

Fm. 18. Probe in position for gamma-ray measurements. The ·*The instrument used in these measurements was a scintillometer manufactured by auger is 3 ft long. Gibbs and McCallum, 1955. Canadian Aviation Electronics Ltd. 188 189 fitted with a thin casing such as 20-gauge steel tubing or aluminium Measurement of Soil Moisture and Density by Neutron and tubing some 2 in. in diameter; if polythene is used for this purpose Gamma-ray Scattering recalibration may be necessary. The use of the probe on the surface of the soil is possible but requires care. By B. A. Meylan, Dominion Physical Laboratory. The ease with which measurements at various depths may be repeated at the sam7 spots without disturbing the . soil, the rea?y If a compact source of fast neutrons is placed within a homo• determination of moisture contours, and the convemence of obtam­ geneous medium, the neutrons travel radially outward from !he ing results immed_iately without awaitin_g labor~tory determinations, source until they collide with the nuclei of atoms of the surrom:idmg constitute the chief advantages of this techmque. On the other material. In these collisions they may be absorbed or elastically hand, the apparatus costs so!Ile £400, r~quires safety precautions scattered. For the elements usually contained in soils, elastic and trained personnel, and gives approximate measurements only. scattering is the predominant mechanism by which the neutrons lose energy. When the neutron has the same energy as the Soil density may be measured by a comparable technique using surrounding atoms it is said to be a thermal neutron and then, on a gamma-ray source (op. cit.). The apparatus is constructed as the whole, it neither loses nor gains energy. part of the portable soil-moisture instrument described above. From the measurements of soil density and of soil moisture by Of the elements in soil, hydrogen is by far the most effective volume, the soil moisture by weight is calculated. in slowing neutrons down . because it has a mass very nearly that of a neutron and its neutron cross section (that is, the probability that a collision will occur) is very high. Consequently in the sml around the source of fast neutrons there is a dense spherical cloud of slow ( that is, thermalised) neutrons, the density and extent of the cloud depending on the amount of hydrogen present. If there is a lot of hydrogen, the cloud is dense and compact, and if there is little hydrogen, it is less dense and will extend further. The hydrogen in most soils occurs almost entirely in the soil water and thus a measure of the number of slow neutrons near a source of fast neutrons will give a measure of the moisture content. It has been found that provided the moisture content is measured on a volume basis, a single calibration curve will suffice for most soils. In relatively homogeneous and uniformly moist soil hC?rizons th_e method measures the moisture content of a sphere of sml approx1• mately 12-18 in. in dia!Ileter, the volume b_eing greatt:st _at !ow moisture contents. In honzons that are not umformly mmst 1t gives measurements that integrate the moisture content of a volume of soil of irregular size and shape determined fargely by the moisture pattern. Measurements of moisture content, of co_urse, cann_ot ~e interpreted in terms of water table unless the moisture tension 1s known. Since some elements such as chlorine and particularly boron are very strong absorbers of slow neutrons, errors in the estima_ted moisture content occur when the soil contains appreciable amounts of these elements. The measurements are also affected by soil horizons rich in organic matter which contains hydrogen. Under such conditions, the calibration of the apparatus is adjusted with the aid of a standard, but little or no recalibration is necessary when measuring soils that are similar. Instruments suitable for field measurements utilising this technique have been developed in a number of overseas laboratories (Belshaw, Cuykendall and Sack, 1950; van Bavel, Underwood, and Swanson, 1956· Hol~es and Turner, 1958; Phillips, Jensen, and Kirkham, 1960: and van Bavel, 1961). A portable instrument designed and constructed · at the New Zealand Dominion Physical Laboratory is about 12 in. tall, 10 in. long, and 6 in. wide, weighs about 12 lb, and has a probe about 2 in. in diameter and 18 in. long. In use, the probe is lowered into a hole in the soil. Where measurements are repeated from time to time, the hole is capped when not in use and may be 191 APPENDIX 7 - Provisional Classification of Soil Clays with M Prefixes used for Special Purposes* · APPENDIX 8 - Kind, Composition, and Status of Indigenous Vegetation By M. Fieldes, Soil Bureau. By A. P. Druce, Botany Division, Department of Scientific The clays commonly found in parent materials and other horizons and Industrial Research. are classified provisionally as follows: gJ The following indicates the information required to record sd Prefix indigenous and associated exotic vegetation for the purpose of soil m~ Classification of Clays (for Dominant sc: Constituents) surveys (seep. 47; for a more detailed method see Druce, 1959). SC2 1. Amorphous hydrous colloids 105 Allophane (Si-Al; ex rhyolitic or andesitic SU/ glass) ...... Allo­ Kind of Vegetation Hydrous felspars (Si-Al; ex felspar) ...... Hydrofelso- The kind of vegetation is recorded as forest, scrub, fernland, ~h1 Hydrous alumina (Al; ex basic and ultra­ tussock land, shrub-tussock land, swampland, herbfie1d, etc. If the m basic minerals) Hydroalumo­ vegetation is not continuous (that is, if bare ground is present) the of1 Palagonite (Si-Al; ex basalt or basaltic percentage area covered by the particular kind of vegetation is glass) Palago- th~ estimated. an 2. (Crystalline) Layer silicates ot Composition th~ a. Micaceous a l Weakly hydrated mica · Mico­ The species or groups of species recorded are those likely to Illite .... Illo­ contribute most to the litter of leaves, bark, twigs, and branches. lit~ Clay-vermiculite Vermo­ The minimum number of species and groups it is desirable to know Montmorillonite Moro- is not great; they are listed below: b. Kaolinitic :~ M etahalloysi te coJ Kaolinite }Kao- Trees* me Group 1: Kauri, cedar, and the podocarps - rimu, miro, matai, foj 3. Crystalline oxides and hydrous oxides totara, Hall's totara, kahikatea, silver pine, toatoa, and tanekaha. a. Of silicon Group 2: Beech trees - hard beech, black beech, mountain beech, mJ Primary quartz 1s ·1· silver beech, and red beech. ma Secondary quartz j l lCO- mo b. Of aluminium Group 3: "Broadleaved" trees - taraire, tawa, puriri, mahoe, me Gibbsite Gibbso- fuchsia, lacebark, pukatea, titoki, hinau, and maire, and the soi c. Of iron "coastal" subgroup of karaka, ngaio, kohekohe, and pohutukawa. paj Goethite Group 4: Kamahi and towai (tawhero), northern and southern mtl Lepidocrocite rata, tawari, quintinia, toro, rewarewa. kn1 Haematite fFerro­ ~ Magnetite J are d. Of titanium Shrubst mo Anatase Titano- of Group J: Ericoid shrubs - manuka, kanuka, Spanish heath (Erica ho1 For special investigations the phases of fulvic soils, for example, /usitanica), tauhinu ( Cassinia spp.), mingirningi ( Cyathodes may be illo-fulvic, vermo-fulvic, moro-fulvic, kao-fulvic, etc. Suitable C. SUCl juniperina and fascicu/ata), Dracophyllum spp. \ the adjectives can be added as required to show subordinate clay Group 2: Spiny shrubs - matagouri or wild Irishman (Discaria wbJ constituents. toumatou), gorse (U/ex europaeus), hakea (Hakea spp.). ] *Modified after Fieldes. 1958. Group 3: "Broadleaved'' shrubs - rangiora, wineberry, tutu, five­ finger, koromiko (Hebe spp.), Coprosma spp., Himalayan ~ honeysuckle (Leycesteria formosa). 19! Group 4: Shrub composites with broad, leathery leaves - leather­ 19~ wood ( O/earia spp. and Senecio spp.). ~b~ Group 5: Broom (Cytisus scoparius), lupin (Lupinus arboreus). has •Refer to The Trees of New Zealand by Cockayne and Turner (1958), and Trees and Shrubs of New is 1 Zealand by A. L. Poole and Nancy M. Adams (1963). fro tSee Poole and Adams (op. cit). 192 193 Pern~ Examples Bracken (Pteridium aquilinum var. esculentum) Forest Histiopteris incisa Primary red beech - silver beech- kamahi - tawari - quintinia forest Scented fern (Paesia scaberula) Modified primary red beech - silver beech forest Crown fem (B/echnum discolor) Modiijed primary silver beech forest (50 per cent cover of trees) Common blechnum (B. capcnse) Cut-over primary rimu-miro-kamahi forest Tree-ferns - ponga or silver tree-fern (Cyathea dealbata), mamaku Cut-over primary rimu-rata-hinau-tawa forest or black tree-fern (C. medu/laris), Cyathea smithii. weki Secondary tawa-mahoe forest (J)icksonia squarrosa), and weki-ponga (D. fibr(?sa) Secondary hard beech- kamahi forest

Tussock Grasses Scrub Hard or fescue tussock (Festuca novae-zelandiae) Primary leatherwood (Olearia colensoi) scrub Silver or poa tussock (Paa caespitosa - several kinds) Modified primary leatherwood (Senecio elaeagnifolius) scrub Red tussock (Danthonia sp. - several kinds) Secondary fuchs1a-wineberry scrub Snow tussock (Danthonia spp. - many kinds. several similar to Secondary tauhinu scrub red tussock in tolerating poor drainage) Secondary manuka scrub (75 per cent cover) BJue tussock (Paa colensoi - several kinJs) Tussock Land Exotic Pasture Grasses ( associated with indigenous vegetation Primary snow tussock land in second growth) Modified primary red tussock land Yorkshire fog (Holcus lmuitus) Secondary silver tussock land Sweet vernal (Anthoxantlzum odoratum) Danthonia spp. Shrub-tussock Land Browntop (Agrostis tenuis) Primary Olearia-Danthonia shrub-tussock land Secondary Dracophyllum-Danthonia shrub-tussock land Other Plants Raupo (Typha muel/eri) Flax (Phormium tenax) Mountain flax (P. co/ensoi) Toetoe (Arundo spp.) Cutty-grasses (Gahnia spp., Carex spp., Mariscus ustu/atus) Rushes (Juncus spp.) Mountain daisies ( Celmisia spp.) Maori onion (Bulbinel/a hookeri) Scabweed (Raoulia spp.)

Status If possible the vegetation at the site is recorded as primary, that is, vegetation which has developed parallel with the soil under the influence of the original biotic factors; modified primary, that is. primary vegetation which has been altered as a result of new biotic factors (introduced animals and plants); cut-over primary, that is, primary vegetation from which the millable trees have been removed; or secondary, that is, vegetation which has developed as second growth either by direct succession or indirectly through pasture after destruction of primary vegetation. In the last case a new development cycle of soil and vegetation is initiated.

*See New Zealand Ferns by Dobbie (1951), and A Book of Ferns by Stevenson (1959). 194 APPENDIX 9 - Composition, Status, and Classification of white clover together with other high-producing pasture plants, Pastures, and Aid to Identification of Common Grasses and depending on the seed mixture sown and subsequent management, Clovers as follows: Grasses By J.P. Widdowson, Soil Bureau. Perennial ryegrass (Lolium perenne) Pasture, as a kind of vegetation, refers to grassland used for the Short rotation ryegrass (Lolium multiflorum x L. perenne) - grazing of livestock, whether it be unmodified tussock land, or H.1 ryegrass sown grassland following the clearing of scrub or forest, or Timothy (Phleum pratense) -Thrives on moist conditions following cultivation. It is a plant community characterised by Prairie grass (Bromus catharticus) - As a special purpose a few dominant grasses and, generally, by one or more clovers, pasture and a number of weeds. The dominant plants present within a Meadow fescue (Festuca pratensis) -Slow to establish given pasture depend on the species sown, the nutrient and Paspalum (Pasp~lum dilatatum) N~d warm climate; mainly moisture status of the soil, the climate, and the grazing management. Kikuyu (Penmsetum clandes-l m northern part of North For soil survey purposes, the composition, status, and classification tinum) Island of pastures are recorded. Kentucky bluegrass (Poa pra- tensis) Occasionally present Composition Annual poa (Poa annua) On a given site, the two or three species of grasses, clovers, or •Clovers weeds that dominate the association are noted, for example, White clover (Trifolium repens) ryegrass - white clover pasture, browntop - yorkshire fog - suckling Red clover (Trifolium pratense) clover pasture, and salicornia - sea barley grass pasture. If required, additional species in the pasture are listed in order Without irrigation th~e pastures are confined to areas with rain­ of importance. These minor constituents are often indicators of falls in excess of 30 in. per annum. In the North Island they are soil fertility, moisture status, management, etc., and may provide extensive in the Waika,to, around Gisborne and Napier, and in the additional useful information about the site; for example, barley Manawatu. In the South Island they are extensive in Southland, grass and scotch thistle indicate an opening of the pasture sward, and they occur in Ellesmere County in Canterbury and under buckshorn plantain is indicative of saline conditions, and annual irrigation in mid Canterbury and Central Ota:go. poa generally indicates high fertility and a plentiful supply of soil moisture. Status 2. Pastures of Soils that are Very Poorly or Poorly Drained The status (see p.47) of the pasture on a given site is recorded together with management details, for example, vigorous two-year ryegrass - white clover Pastures of badly drained soils consist characteristically of plants, dairy pasture, temporary short-rotation ryegrass - red clover hay pasture, such as those in the following list, which thrive in permanently moist runout browntop - yorkshire fog pasture. soil conditions and tolerate periods of inundation: A. Plants that Thrive on Edges a/ Lagoons and are Fre- Classification of Pastures quently Inundated In the following classification* the main species of grasses and Reed sweet grass ( Glyceria aquatica) - Grows submerged in water clovers that may be encountered on a site are grouped according Mercer grass (Paspalum distichum) to the habitat in which they most commonly occur. Sev~ral species, Floating sweet grass (Glyceria fiuitans) however, such as browntop, sweet vernal, and even perenmal ryegrass, Reed canary grass (Phalaris arundinacea) - Not common are very adaptable and occur over a wide range of habitats. B. Plants that Thrive on Wet Soils (listed in order of decreas- 1. Pastures of Fertile Soils Where There is No Limiting ing tolerance to moisture) Factor to Production Meadow foxtail (Alopecurus pratensis) Knee jointed foxtail (A. geniculatus) With an adequate supply of nutrients and moisture, adequate Rough stalked meadow grass (Poa trivia/is) drainage, and favourable temperatures during the growth period, Timothy (Phleum pratense) the fertile habitat is characterised by vigorous swards of ryegrass and Creeping bent (Agrostis stolonifera) tl'fhis classification is based on that of Saxby (1956) and includes data from Yorkshire fog (Holcus lanatus) Hilgendorf (1935) and Madden (1940). Tall fescue ( F estuca arundinacea) 197 l

Rushes (Juncus spp.) and sedges (Carex spp.) are also present in Clovers many places. Legumes are usually absent but on the better-drained Suckling clover (Trifolium dubium) fringes of the habitat the following may occur: Clustered clover (T. glomeratum) Lotus major (Lotus pedunculatus) Striated clover (T. striatum) Strawberry clover (Trifolium fragiferum) White clover (T. repens) 4 Pastufes of Moderately Fertile and Low-fertility Soils · Without Seasonal Moisture-deficiency ·3. Pastures of Moderately Fertile and Low-fertility Soils While high-fertility grasses and <::l~>Vers may be sown. on the With Seasonal Moisture-deficiency moist soils of moderate to low fertility they seldom persist; low­ fertility species such as browntop become dominant and suppress Pastures on the drier soils of moderate to low fertility are con­ the sown species. In the North Island the browntop-dominant sidered in two subgroups, the pastures of the periodically dry soils astures occur in a narrow belt which for the most part is further of the South Island and North Island respectively: fnland than the danthonia-dominant pastures; they ext~nd. from the Wairarapa to the East Cape and are also present m mland A. South I stand Taranaki. In the South Island a similar narrow belt of brownt<;>P­ In the South Island, these pastures are found on the east coast dominant pastures extends southward along the downs and foothills from Marlborough to North Otago with rainfalls of less than 30 in. of Canterbury to the Waitaki River; other areas occur in the per annum. The following species occur in pastures where the soils downs and foothills of South Otago. The main pasture plants are: are subjected to moisture deficiency during the summer: Grasses Grasses Browntop (Agrostis tenuis) Cocksfoot (Dactylis glomerata) Sweet vernal (Anthoxanthum odoratum) Perennial ryegrass (Lolium perenne) Yorkshire fog (Holcus lanatus) Crested dogs tail ( Cynosurus cristatus) Danthonia spp. Phalaris (Phalaris tuberosa) Clovers Sweet vernal (Anthoxanthum odoratum) Old man twitch (Agropyron repens) Suckling clover Chewings fescue (Festuca rubra subspecies commutata) Lotus pedunculatus and L. hispidus- In North Island areas Browntop (Agrostis tenuis) Many weeds abound in these browntop-dominant associations. Goose grass (Bromus mollis), barley grass (Hordeum muri­ They include hawk weed (Crepis capillaris), catsear (Hypochaeris num), and hair grass (Vulpia sp.) are likely to be present radicata), ribgrass (Plantago lanceolata), and self-heal (Prune/la where the sward has opened. vulgaris). . Clovers Included in this group of pastures in the South Island are the Wllite clover (Trifolium repens) lowland tussock lands. Just as the browntop-dominant association Suckling clover (T. dubium) has responded to topdressing with lime and superphosphate and Subterranean clover (T. subterraneum) oversowing with clovers (and in some cases grasses), so too have Lucerne (Medicago sativa) the tussock lands responded. Plant nutrient deficiencies have been the chief problem and are now being corrected; legumes are On shallow soils white clover and ryegrass do not persist with improving the nitrogen supply so that better grass species can be prolonged periods of moisture deficiency. grown. Thus, with correct management, the pastures on these moist soils of moderate to low fertility can be improved to the level of B. North Island pastures in Class 1. In the North Island these pastures are dominated by danthonia and extend from the East Cape to the Wairarapa where on much of S. Pastures of Windblown Sand Country the hill country the soils are shallow and dry out rapidly during Pastures on windblown sand country along the coastline, and summer. The following species are characteristically present: in some cases inland ( as near Cromwell in Central Otago) , are of Grasses limited extent. The main species are: Danthonia (Danthonia spp.) Marram grass (Ammophila arenaria)} Ratstail (Sporobolus capensis) Silvery sand grass (Spinifex hirsutus) On moving sand New Zealand rice grass (Microlaena stipoides) Pingao (Scirpus frondosus) . Hair grass (Vulpia bromoides) Sand fescue (Festuca littoralis) } Sweet vernal (Anthoxanthum odoratum) Brome (Bromus arenarius) Also present to a lesser extent are blue grass (Agropyron scab­ Sand bent (Deyeuxia billardieri) On fixed sand rum), silver hair grass (Aira caryophyllea), and plume grass Harestail (Lagarus ovatus) (Dichelachne crinata). Indian doub ( Cynodon dactylon) 198 199 Where rainfall is adequate on the older fixed sand dunes, rye­ key by Elser (1953) ; for further information reference may be grass - white clover pastures of Class 1 can be established following made to Allan (1940), Hilgendorf (1952, 1961), and McNeur an initial period of consolidation and building of fertility; they can (1956) be maintained by careful management to prevent a weakening of the turf and exposure of the underlying sand to erosion. _,..,. -~- Leaf blade ______6. Pastures of Saline Soils Pastures that are characteristic of saline soils (see p. 112) are found in many places adjacent to, or associated with, salt-meadow vegetation which occurs near the mouths of tidal rivers or near the shores of estuaries and saline lakes. They are found also in small areas on the salty soils of Central and North Otago. Although plants found in salt meadow have the ability to tolerate appreciable concentrations of soluble salts, most pasture plants are sensitive to soluble salts even at low concentrations." For example, seed germination may be impeded at concentrations of less than Ligule . O·l per cent, white clover does not persist above O·l per cent, and ryegrass does not thrive above 0·2 per cent. As the salinity of the soil increases, pasture plants are replaced by other plants that are able to tolerate greater concentrations of soluble salts; since these plants differ in their tolerance to soluble salts, their presence or absence can be used to estimate the salinity , , of the soil. In moist soils, plants are able to withstand much higher ... ,., salinities than in dry soils, but many species (for example, the annual sea barley grass) are able to complete their life cycle before · the soil dries out and the salinity affects them. @ The following plants, which occur both in salt meadow and in © pasture on saline soils, are arranged in order of decreasing tolerance to soluble salts.* Very tolerant (2·5 per cent soluble salts) Salicornia Salicornia australis Salt fathen ..... Chenapodium g/aucum Three-rib arrow grass ··-·· Trigolochin striatum Salt grass Puccineflia stricta Moderately tolerant (1 · 5 per cent soluble salts) Trifoliate Atriplex ...... ·...... Atriplex spp. Sea barley grass ...... H ordeum marinum leaf Scirpus . . Scirpus spp. Slightly tolerant ( 1 · 0 per cent soluble salts) Selliera ...... Selliera radicans Buckshorn plantain Plantago coronopus Batchelors button Cotula coronopifolia Creeping bent Agrostis stolonifera Aid to Identification of Common Grasses and aovers Most grasses and clovers are readily identified from their seed heads. Since, however, the seed heads may be pr~ent for only a month or two during the year and may not be found at all in a closely grazed pasture, grasses and clovers must often be identified from their vegetative characteristics, that is, the leaves, stems, and roots (fig. 19). The following aid to the identification of common © grasses and clovers found in New Zealand pastures is based on a FIG. 19. Diagnostic features of common grasses and clovers: (a) *Compiled from Dixon and Harris (1938); Hughes, Hodgson, and Harris (1939); prairie grass, (b) ryegrass, (c) red clover. Drawn by G. C. and Evans (1953). Jackson. 200 201 Grasses Barley grass .Bud rolled, hairs on leaves and Noh-Twitchy Grasses (without rhizomes) sheath, ligule short, clasping ears Sweet vernal Bud rolled, hairs on leaves and Distinct coloration at base of sheath sheath, ligule short, ears absent and Red replaced by hairs, characteristic scent Perennial ryegrass Leaf bud folded, hairless, ligule short, and taste small ears, lower surface of leaf Ratstail Bud rolled, hairs on edges and base shiny of leaf, ligule absent and replaced by Chewings fescue Bud 'folded, hairless, ligule often ring of hairs, ears replaced by hairs, absent, shoulders in place of ears, leaves tough and harsh sheath base pink when young and brown when dead Italian ryegrass ...... Bud rolled, hairless, ligule short, ears Twitchy Grasses ( with rhizomes) present, lower surface of leaf shiny, Poa pratensis Bud folded, hairless, ligule short, seeds awned. ears absent, canoe tip Meadow fescue Bud rolled, hairless, ligule short, ears Kikuyu grass Bud folded, leaves hairy at base, present, upper surface and edges of hairs on sheath, ligule replaced by leaf rough and cutting hairs, vigorous stolons Tall fescue Very simila1· :to meadow fescue, but Browntop Bud rolled, hairless, ligule short, ears much taller and coarser absent, lower side of leaf dull Phalaris or Canary grass Bud rolled, hairless, ligule- very long, Old man couch Bud rolled, hairs on leaf and sheath, swelling on ·base of stem at ground ligule small, clasping ears, rhizomes level have sharp hard tips Yorkshire fog Bud rolled, hairy leaf and sheath, Paspalum Bud rolled, hairs on base of leaf and ligule long, ears absent, sheath white sheath, ligule long with hairs behind with red veins it, cigar-shaped leaf Yellow Creeping fog As for yorkshire fog but with Crested dogstail Bud folded, hairless, ligule short, rhizomes ears absent, lower surface of leaf shiny

Clovers No distinct coloration at base of sheath True Clovers (stipules membraneous and transparent and Cocksfoot Bud folded, hairless, ligule long, ears veined with green or red, leaflets with stalks of equal length absent, flat sheath except suckling dover) Floating sweet grass Bud folded, hairless, ligule long, ears Red clover Leaves and stems hairy, stems erect absent, leaf with canoe tip, usually not creeping, stipules end in two long growing in water with leaves floating points usually hairy, leaflets ovate Annual poa Bud folded, hairless, ligule long, Alsike Leaves and stems hairless, stems leaves with canoe tips and ,trans­ erect, stipules long and pointed, versely wrinkled, generally in flower leaflets similar to red clover Danthonia species Bud folded, sparse hairs on leaves White clover Leaves and stems hairless, stems and sheath, ligule_absent and replaced creeping, stipules are pointed and lie by tuft of silky hairs, leaves narrow closely along stem, leaflets heart­ and greyish green · shaped Timothy Bud rolled, hairless, ligule lon:g, ears Strawberry clover Leaves and stems hairless, stems absent, bulb-like swellings at base of creeping, leaflets long and oval, seed stem heads become swollen and look like Prairie grass Bud tolled, hairs on leaves and strawherries sheath, ligule long, ears absent, Suckling clover Annual, stems and leaves usually sheath closed hairless, stems creeping - not stolons, Goose grass ...... Bud rolled, hairs di:l leaves and leaflea small and heart-shaped with sheath; ligule short and raggett, eani central leaflet stalk longer than other absent two, flowers small and yellow 203 Subterranean clover Annual, leaves hairy particularly on APPENDIX 10 - Hydrological Characteristics of Soils lower surface, stems creeping - not stolons, leaflets heart-shaped and By A. P. Campbell, Ministry of Works. -round and may have black or brown or purple markings depending on This appendix is included in recognition of the need for variety defining the hydrological characteristics of soils. The classifications Haresfoot trefoil Annual, leaves and stems hairy, now used are still in process of development and are not yet stems erect branched and reddish, supported by enough hydrological data for any complete scales leaflets long narrow and greyish of measurement to be established. green, flower head brush-like hairy A generalised classification of the hydrological characteristics of and pink soils is given in the map "Provisional Hydrological Regions of New Zealand" (in preparation), which is in the nature of a general Medicks (stipules toothed and coloured green, central leaflets guide to assist in the more detailed classifications of areal hydro­ on longest stalk, spike produced from end of midrib leaves logy. Detailed mapping to show particular characteristics such as trifoliate) ' water yield, flood potential, erosion status, etc., will follow the collection and analysis of run-off and rainfall data for areas under Lucerne Leaves sometimes downy on lower survey. Catchment measurements and all other hydrological data surface, stems erect, leaflets oval with are .published annually, as they become available, in the Hydrology toothed edge on upper half, flowers Annual of the Soil Conservation and Rivers Control Council, usually purple, black spiral seed pod which has been issued since 1953. Black medick Annual, hairs on stem, stems creep­ ing - not stolons, stipules large and toothed, leaflets heart-shaped, flowers yellow and small Flood-producing Characteristics Burr clover ...... Annual, leaves and stems hairless stems creeping, stipules finely The method of measuring the flood-producing potential is given toothed, leaflets heart-shaped, seed by the standard empirical formula adopted for flood estimation in pod with two rows of hooks forming New Zealand (Ministry of Works, 1961) namely: burr Qp=CRSA¼ Lotus (bird's foot trefoils - stipules large and leaf-like so Where Qp = flood peak in cusecs; that each leaf appears to have five leaflets, flowers yellow) C = a constant depending on catchment characteristics; = rainfall factor; Lotus major ..... Leaves and stems usually hairless, R stems erect, 8- 12 flowers in head S = catchment-shape factor; Lotus hispidus Leaves and stems hairy, 3-4 flowers A = catchment area -in square miles. in head The constant C is determined from a consideration of the slopes of the catchment and the effect of soil infiltration and vegetation (the vegetative cover including litter). The infiltration-vegetation subfactor is of major importance in classifying the effect of soil on flood sizes. Hydrological data are being collected to establish definite scales of measurement which can now be estimated only approximately. The scale of measure­ ment in table 8 refers to catchments of a particular size ( 5 miles in length), because the soil and vegetation of catchments has a much greater influence on flood peaks for small areas than it has on flood peaks for large areas. District data on flood measurements are being recorded to ~ssist in the closer estimation of this subfactor, and available information will appear in summarised form in future revisions of the formula. Measurements to express the average slope of catchment areas are of prime importance in estimating flood potential. The standard formula includes a simple method for estimating the average slope of the catchment area by analysis of the slope of the main stream, this giving results approximately equivalent to those obtained directly by topographical slope measurements. 205 TABLB 8. VALUES FOR CATOIMENT INFIL1RATION-VEGETATION (Soil Conservation and Rivers Control Council, 1961b). The sedi~ CHARACTERISTICS ment discharge from catchments is usually expressed in a formula which relates sediment discharge to run-off (Jovanovic and Vukcevic, Infiltration_- 1958): Soils Vegetation Vegetation Subfactor I where~G = instantaneous sediment discharge, usually in tons per second; Impervious soils (such as clay soils Mainly bare surfaces .. 1·2 with poor structure, e.g., north­ Average short-graz.ed pastures . . 1 · 1 A = a coefficient which is a measure of the erosional ern yellow-brown earths) 30 per cent of area in long grass, scrub, 1 ·0 characteristics of the catchment; or bush Q instantaneous rate of stream flow in cusecs; Any soil if saturated is included 60 per cent of area in long grass, scrub, 0·9 = here or bush . n = a number reflecting how sediment discharge varies 100 per cent of area in long grass, scrub, 0·8 with the magnitude of the storm. Values of n are or bush commonly between 1·5 and 2·5. Moderately absorbent soils (such Mainly bare surfaces . . . . 1 · 1 as medium textured soils with Average short-grazed pastures .. 1 ·0 The coefficient A can be used to class a catchment as weakly, good structure, e.g., southern 30 per cent of area in long grass, scrub, 0·9 moderately, or strongly erosive, while the number n indicates the yellow-brown earths) or bush rate of change of erosion with . intensity of storm. Available data 60 per cent of area in long grass, scrub, 0·8 or bush are published in the Hydrology Annual (op. cit.). 100 per cent of area in long grass, scrub, 0·7 or bush Ground-water Depletion Absorbent soils (such as deep Mainly bare surfaces .. 1 ·0 yellow-brown sands and pumice Average short-grazed pastures . . 0·9 Hydrological measurement of base-flow recession curves provides soils) 30 per cent of area in long grass, scrub, 0·8 a measure of the water storage in the soils and underlying rocks or bush 60 per cent of area in long grass, scrub, 0·7 of catchments during dry-weather periods. Standard methods of or bush observing and recording· information have been described (Soil 100 per cent of area in long grass, scrub, 0·6 or bush Conservation and Rivers Control Council, 1961a).

Infiltration and Surface Detention Data for the infiltration-vegetation subfactor can be provided in a generalised way from measurements of flood peaks and rainfall, but for close study of · rainfall and run-off relationships, and of the part which soil plays in these relationships, run-off records are analysed to produce more detailed information. Curves are derived which show the variation of infiltration with time during continuous· storms. These assist in deriving the water.. holding capacity of catchments and show the effects of such proper­ ties as surface compaction. Other data are obtained to record the depth of water temporarily detained on the surface of a catchment for various rates of flood run-off. This surface · detention is the measure that indicates the separate influence of vegetation. With sufficient records, an analysis of seasonal variation of these quanti­ ties can be made. The objective in current work is to r~ord suffi­ cient ~ata to outline typical conditions for ·each major soil under various conditions of vegetation. A further objective is the correla­ tion between these measurements and measurements of soil structure and moisture.

Erosional Characteristics Hydrological measurement of the erosional characteristics of a whole catchment is provided by suspended sediment sampling during floods to establish values for suspended sediment rating curves 206 207 APPENDIX 11 - Land-capability Classification in New "The subclasses represent convenient groupings of subordinate Zealand, with Special Reference to Soil Conservation characteristics. A land-capability class is determined by the degree of limitations in land use, together with the hazards involved. Th~ following notes have been compiled from information Within a given land-capability class the subclasses are determined supplied by officers of the Soil Conservation and Rivers by the kind of limitation. For example, within class III land, suited Control Council, Wellington. , for <;:ultivation but subject to severe hazards, most frequently we have sfoping land subject to water erosion, but we also have The land-c~p~bility classes used by soil conservators in New smooth land subject to wind erosion and wet land that produces crops only if drains are installed and maintained. ZealaJ?,d are s~mllar to those used in the United States (Soil Con­ "Within each subclass the land that is suited for essentially the servation Service, 1954, p. 27) which are outlined below: same kind of management and the same kind of conservation treat­ Land-use Suitability Land-capability Class (Degree of ment is designated as a land-capability unit. A land-capability unit is (Broad Groupings) Limitations for Use) essentially uniform in all major characteristics that affect its I Few limitations. Wide latitude for management and conservation. It is the smallest unit recognised in use. Very good land. ( Green on the la!ld-capability classification, although greater detail may be coloured map.) i"ecogmzed for some local purposes in mapping." (Loe. cit., p. 28.) II Moderate limitations in use. Good In_ assessing the use-capability of land ·in New Zealand, "the land. (Yellow) classifier attempts to define within several broad classes what is III Severe limitations in use [for culti- the safe potential use for each land unit. The land unit in this Suited for cultivation vated crops]. Regular cultivation case is any area within which the characteristics of soil, slope, possible if hazards are provided vegetation, and erosion are broadly similar. The degree of refine­ against. Moderately good land. ment used in defining these characters depends upon the intensity (Red) or scale at which the classification is to be made. ITV Very severe limitations in use [for "Safe potential use means the use to which the land may be put cultivated crops]. Suited for occa- without causing . a deterioration in its ability to give a permanent sional cultivation or for some kind of sustained yield, and without causing a deterioration in adjacent or I relate

[•Class y1 -:- typical stable hil~ country needii:tg good farming practices for permanent prod~cllon, Class VU - typical unstable hill country needing special conservation practtces.) 208 209 APPENDIX 12 - The Preservation of Soil Monoliths position against the soil. A U-shaped tr~ncl~ is cut ~ehind the board and the top of the soil column which 1s !irmly ~ied on th~ By W. R. Owers, Soil Bureau. board with a linen strip, and this procedure 1s co1;1tmued until the whole column is safely secured to the board. While the lower The value of preserving soil monoliths has been recognised by soil horizons are being detached, the monolith is supported for safety scientists for many years. In Technical Note No. 7 of the Imperial by wooden props. Bureau of Soil Science ( 1930), Polynov, Baity, and Schokalsky ( of the Dokuchaiev Institute of Soil Science), and also Miklas­ zewski, describe methods for collecting a complete soil monolith; Mounting Schalcht describes a method of taking a soil section in situ · using If the soil in the metal or wooden box is rather moist, it. is adhesives for cementing the section on a mounting; .and Prescott allowed to dry for a few days so that it can absorb t~e se~lmg describes a method for preparing an artificial section in the solution. Its surface is trimmed smooth and sealed with dilute laboratory. cellulose acetate solution. To improve bonding . betwee~ the The methods here described for preserving soil monoliths include mounting board and the soil, about 18 1 in. galvamsed nails are procedures for collecting the monolith in the field and for mounting hammered through the board so that they will penetrate into the it later. The ordinary method of collection is similar to that soil column when this is placed upon it. The surfaces to be described by Polynov and his co-workers (loc. cit.), but the bonded are both coated with concentrated . cellul~se acet~te procedures for preservation in plastic have been made possible solution, care being taken to avoid breaking_ the seah~g ap~l!ed more recently by the development of suitable plastic materials previously to the soil. The mounting board 1s _placed m P<;>sit~on and, in the main, they follow methods described by Smith and on top of the soil column, with part (ab_out 6-9 m. long) ~roJecting Moodie (1947, 1952). beyond it to carry the name of the soil, and the whole 1s . turned over and the box lifted off immediately. Where the monolith has been mounted in the field as described above, the mounting board Equipment and Materials is of course already in position and this procedure is omitted. For collecting the monolith, the equipment required is a spade, The solutions are allowed to dry before final trimming of the butcher's knife, and metal or wooden box (8 in. X 4 in. X 36 in.) monolith. The soil structure is exposed with the ~id of a den!is(s or mounting board and linen strips (18 in. X 6 in.). For mounting, pick which is levered along structural planes while ~xcess soil 1s the materials needed are a mounting board of plywood (6 in. X being removed by vacuum cleaner or compressed air. When the ½in. X 48 in.), cellulose acetate solutions ( dilute, 140 g cellulose monolith is reduced to less than 1 in. in thickness and is showing acetate per gallon acetone; concentrated, 450 g cellulose acetate per the structure plainly, it is allowed to dry thoroughly before being gallon acetone), and vinylite resin solution (240 g of vinylite resin, saturated with the vinylite resin solution. About 1 litre of this VYHH or equivalent, dissolved · in a 2: 1 mixture of acetone and solution is generally used. for each monolith and when i~ has methyl isobutyl ketone and made up to one gallon). evaporate_d it le~ves the soil ~ealed . and hard~ned. Excess ':ll01st1;1re in the soil at this stage combmes with the resm and turns 1t white. Collection The edges of the monolith are trimmed back to the width of the board,. and sides are fitted for protection and to improve its The Soil Bureau has employed successfully two methods for appearance. collecting monoliths. The usual procedure of collecting in a metal or wooden box has been found to be quick and straightforward. The surface of the soil profile in a pit or road cutting is trimmed smooth, and the monolith to be taken is outlined by placing the box over it and tracing the outline of the box upon the soil profile. With this outline as a guide, the surrounding soil is trimmed away until the soil column fits the box which is eased over it. The box and soil column are then removed by forcing a spade behind them and levering them away from the cutting. The surface of the severed soil column gives a good indication of the appearance of the final mounted surface. . Monoliths that are difficult to collect by this method (for example, from loose or stony soils) are obtained by cementing a mounting board directly to the soil. The surface of the soil profile is trimmed as smooth as possible and sprayed with dilute cellulose acetate solution. The board on which the soil is to be mounted is ~lso treated with dilute cellulose acetate solution and a linen strip 1s placed on the treated surface to assist bonding. When the solutions are dry, the board and soil profile are coated with the concentrated cellulose acetate solution and the board pressed into

210 211 APPENDIX 13 - Ratings for Some Chemical Analyses of New Zealand Soils Total Nitrogen (Total N, or_N)..:__ ___---:------

These ratings are after Metson (1956), except the phos­ Rating Range phorus section which is by W. M. H. Saunders, Soil Bureau. (%) Single-factor maps of New Zealand showing the areal dis­ Very high >1·0 tribution of variol.Mi ratings are in the course of publication by the New Zealand Soil Bureau. High .. 0.6-1.0 Medium 0.3-0.6 Low . . 0.1-0.3 Phosphorus (P) Very low <0·1

Range P (mg %•) Extracted By Carbon/Nitrogen Ratio (C/N) Rating Rating Range Truog Reagent I N H I SO, Very high Very high >24 High >5 >40 High .. 16-24 Medium 3-5 20-40 Medium 12-16 Low 2-3 10-20 Low .. 10-12 Very low 1-2 5-10 Very low <10 <1 <5

·ltrng / 100 g soil Cation-exchange Capacity (CEC), Total . Exchangeable Bases (TEB), and Percentage Base Saturation (%BS) NOTE-Phosphorus extracted by Truog reagent ( · 002N H2 S0 at pH 3) gives a measure of plant-available phosphorus for most New4 Range Zealand soils. Anomalous high values are obtained on some recent Rating soils probably because of the presence of apatite in the sand fraction. CEC TEB BS Phosphorus extracted by N H2 S04 (normal sulphuric acid) is an (me. %)• (me.%) (1/J estimate of the total inorganic phosphorus less the most difficultly acid-soluble. Within soil suites the values generally decrease with Very high >40 >25 80-100 increasing stage of soil development. High 25-40 15-25 60-80 Medium .. 12-25 7-15 40--60 Low 6-12 3-7 20-40 Very low .. <6 <3 0-20 •Milliequivalents/100 g soil. Organic Carbon (Org. C, or C) and Organic Matter Exchangeable Calcium (Exch. Ca), Magnesium (Exch. Mg), Org. C Organic Potassium (Exch. K), and Sodium (Exch. Na) Rating Range Matter Nomenclature for Soils with % Range Peaty Organic Matter % Very high >40 >70 Peat Rating I Exch. Ca I Exch.--~ Ma I Exch. K I Exch. Na 30-40 50-70 Peat (loamy, sandy, etc.) 20-30 35-50 High Peaty (loam, sand, etc.) Very high .. >20 >6 >1·2 >2 10-20 17-35 Slightly peaty (loam, sand, etc.) Medium 4-10 7-17 High .. .. 10-20 3--6 0·8-1 ·2 0·7-2 Low 2--4 3·5-7 Medium .. 5-10 1-3 0·5-0·8 0·3-0·7 Very low <2 Low .. .. 2-5 0·3-1 0·3-0·5 0·1-0·3 <3·5 Very low .. <2 <0·3 <0·3 <0·1 NoTE-These ratings have been modified by A. J. Metson and NoTE-lt is assumed that organic matter = Org. C X 1·724 (Waks­ differ slightly from the earlier published standards. t) t man and Stevens, 1930, p. 97). When above 50 per cent, the To convert citric-so_luble K~O figuresf (Eexph~'Agureas~er(e~;1:essed organic matter may be determined by "loss on ignition". their approximate eqwvalents m terms o xc . aa me. % ) , multiply by 34. 212 213 Total Soluble Salts APPENDIX 14 - Methods of Soil Correlation Range Methods of soil correlation have been described 'by Dr Rating Charles E. Kellogg of the Soil Conservation Service of the United States Department of Agriculture (1959b). The me.% % I~·o/cm· IDllllimhoK_(,al) ../cm·t I On Soil following extracts from his paper set out the basic principles (estimated) that are used in attacking this complex and diffi'cult - problem. Very high .. >0·7 >2 >16 For the soil maps to serve their purposes, the kinds of soil shown High .. .. 0·3 --0·7 > 10 on them are defined by common standards and like soils are given Medium 0·8- 2 7-16 4-10 .. 0·15--0·3 0·4- 0·8 4-7 the same names. The system of soil classification is developed, Low .. .. 0·05--0· 15 2-4 maintained, and improved by soil correlation. Soil correlation is Very low 0· 15--0·4 2-4 0·7-2 .. < 0·05 <0·15 < 2 the scientific method by which the set ( or combination) of all the < 0·7 significant characteristics of each soil is specifically compared with . . •Conduct!~ty at 25 0 c of the 1 : 5 extract. the sets of characteristics of the already defined and named kinds tConduct1v1ty at 25° c of the saturation extract. of soils in the natural or taxonomic* system of soil classification and thereby the soil gets its name and its place in the system. l :f~~raJ~~ ~fC:~Ji~~eb~~~~n t~ota~dsalts ~n~ con~uctivity of the ,By extension of meaning in actual operations, the term "soil tion. of the salts. For New Zeal 1 e vad1;1~t10ns m the co~posi­ correlation," as an activity, includes: (1) Standards for the de­ relation is an con itlons an approximate scriptions of the characteristics of the soils and their associated environments; (2) definitions of kinds of soil as specific combina­ 25 Th ~ ~ (millimho/ cm X 0·350 = Tot~l soluble sal~ (%) tions of these characteristics by syntheses of the descriptions of like soils; and (3) development, maintenance, and continual revision rangee O~Xl~e~ff~~:t ~~ sg!fble salts are generally noticed within the of the system of soil classification. yary considerably in their ~~rer~eiie tf~alsasl~lufte ski~d but pl_an!s The first step in soil correlation is the description and evaluation 1 of the sets of soil characteristics in standard terminology. Actually, =i~:J°~; ~°c;il~he e~ects of excess soluble · salts being ~fos~o~r~~ of course, no two soils are completely identical. In this context and "nonsaline" soi~ l;g:;;u!iiyt~~- Tth ~ boundary between "saline" 0 1 we must recall that "a soil" is an indi_vidual three-dimensional body a per cent total soluble salts. on the surface of the earth unlike the adjoining bodies. Those that are essentially alike, wherever located, are included in a "kind of soil". The correct statement that soils are classified into kinds according to their characteristics is deceptively simple. We need to have in mind also the relative significance of the characteristics and how much range of each is permitted within one kind of soil. Characteristics of significance to soil genesis and to soil behaviour under use are given greatest emphasis. Some of the differentiating characteristics cannot be correctly measured in the field but can be correlated, through laboratory research, with accessory characteris­ tics that can be seen and measured in the field. Thus, a full definition of a kind of soil includes a statement of both differentiating and accessory characteristics, of the permissible ranges in each, and of any likely accidental characteristics that may serve as phase distinctions. Commonly such definitions include a definition of the typical or central concept of the kind of soil (as a class, within type, series, family, subgroup, group, suborder, or order) and of the boundary limit, together with the names of the adjoining kinds of soil. The field soil scientist searches out each combination of soil conditions that may be unique. Like ones are abstracted into definitions for a kind of soil.

•Toe basic, countrywide system of ~oil classification is commonly called a "natural" or "taxonomic" system- simply to distinguish it from other systems based primarily on genetic factors, on only a few selected factors, or on interpretations. Recently, engineers have been referring to it as a "pedological" system in contrast to the several engineering SYStems. 214 215 The precise plan of fieldwork for preparing a correlated field Having studied examples of all. t~e kinds of soil in the . ar_ea, legend depends upon data already available. In an entirely new the classifier develops a legend, gr~m~ a number and . descnphon area, the soil classificr-whoe\'er makes up the legend- begins by to each kind of soil. These descnphons are abstractions of all describing the soils in each major combination of the five factors - descriptions he had made in the field as supplemented_ by r~levant climate, living matter, parent material, relief, and age of landform - data from the laboratory on samples. In actual _pract1ce, th1_s . first that he can identify. Where they exist, emphasis is commonly given legend rs a trial. In making fi~ decisi_o!18 he will need add1t1onal those soils that bear the full imprint of the climate and living descriptions and perhaps specific add1honal laboratory . data for matter, because the soil scientist can apply more of what he doubtful cases. Much of this he gets after at least some tnal of the knows from the world literature· to them. Such soils, sometimes legend by mapping. called "normal" soils, are expected on well drained areas of gentle relief from materials of mixed composition - neither very The legend is tested in three primary ways as the work progresses: sandy nor very clayey nor dominated by any particular mineral - (1) Are the units mappable? Can they be sh'?w.n on the map and of sufficient age for the soil horizons to have been clearly accurately and consistently? Some clear and d1stmct taxonomic developed. Such soils belong in soil series that fall clearly within soil units occur in such small areas that they ca~ot b~ show!} the concept of one of the "zonal" soil groups. This does not separately on the maps. These units must be combm~d wit~ their mean that these soils are more impo•rtant than others or that unlike geographic associates into complexes as ma·pprng umts. they need more total emphasis. But it is easier to begin with them (2) Does _the legend have a cl~r pl~ce in it . for each kind of where they are present. One hastens to add, however, that some soil found in the field? If it 1s difficult (mtellectually, not countries contain no "normal" soils in this sense. The soil scientist necessarily physically) to distinguish on~ _kind of soil from another, can have only a general idea of what they would be, if present. the chances are that the two defimt10ns do not meet at a Yet by comparing the existing soils developed under different sets logical boundary in relation to th~ genesis ~f the S?ils. Or of soil-forming factors he can gain useful insights into the effects perhaps some kinds of soil are bemg found m mappmg that these factors have had. have yet to be defined for the legend. Associated in the same climatic area with the soils bearing the (3) Can the predictions abo~t tI?-e many areas of each kind of full imprint of the climate and living matter are many other soil needed to meet the obJechves of the survey, be made kinds of soil resulting from other combinations of vegetation, con;istently and accurately? If areas of the same kind of soil have relief, parent material, and age of landform. Some are steep, significantly different responses to management,. perh~ps the others are flat ; some are wet, others are very limy; and so on. mapping units are too broadly de_fined. If unhke soils have With a clear concept of the "normal" soil the soil classifier can identical responses, perhaps some umts are too narro'YlY defined. organise the other soils in relation to it. Yet it does not follow But before he decides, he must be reasonably certam that the that differences in parent material, for example, have the same soils do not have obvious genetic differences or that differences significance under all other conditions. Differences in texture of in response under other important uses cannot be expected. the C horizon that are significant in the normal position may not be significant in the hydromorphic (wet) position or in the After the legend is tested, numbers are applied to e~ch mappi~g oromorphic (steep) position. unit. For those that co relate with defined, known kmds of soil, Along with the taxonomic units, the soil classifier must also series names are at hand. For those that do not, descriptive names establish any subdivisions of them, as phases, that are essential are used. Thus we may say, "this soil we ar~ loo.king at correla_tes for reaching the practical objectives of the survey. That is, as with Miami silt loam." Or we may say, "this soil we are look1_ng natural units many soil types have fairly wide ranges of slope, at does not correlate with Miami silt loam as now defined, nor with stoniness, and thickness that have no significance to the soil body any other series that we know." in its natural state but that need to be broken into phases for As the soil survey is started in some area, during its progress, and practical maps to predict soil behaviour under cultural conditions. at its close field reviews are made. Although such reviews deal Yet characteristics that are significant and that are used to with all ph~ses of the soil survey work, including the accuracy of separate phases among soils potentially suitable for crop use, may the soil maps, efficiency of operations, and adequacy ?f the , res~lts have a different significance, or none at all, among other soils. for their intended purposes, a large part of the s01l cortefati~n Thus, phases for stoniness may be set up on some soils and not work takes place during the reviews. These reviews have five mam on others having the same range in stoniness because· other soil purposes for soil correlation: characteristics so overshadow the Tange in stoniness that it has no significance. The same may be said of separate soil types for ( 1) Field scie1:1-tists ar~ given _guid_ance on the d~fficu~t pr'?blems small differences in texture. of soil descriptions, soil classification, and the 1dent1fication of This problem of recognising small differences is especially difficult soil boundaries. with soil series that have within their range both arable and (2) They are also given guidance on the m~in_tenance of nonarable soils. There Is an unfortunate tendency, for example, complete field notes and the dev~lopment of descnptive legends. to carry the phase distinctions that are significant in the arable Those in use are ca.-efully checked m the field. part of the range also into the nonarable part where they are not (3) Soil maps are checked for accuracy and for conformity to significant. This wastes time, clutters up the map, and increases the difficulty of interpretation. the legend. 216 (4) Giving at least tenative names to the soils starts early. an old broadly defined soil series into two or more other series As the area is studied and data are accumulated, the soils in that are more specifically defined? (3) How does the soil correlator the area are finally · given tentative names and their places in know when to combine two or more older soil series that were the classification. wrongly separated from one another on the basis of an accidental (5) As the work progresses field scientists are given guidance characteristic? and help to identify the more difficult problems and to arrange There4. are no clear-cut, simple mechanical guides, nor can there for the essential data necessary to resolve the problems. be. Every one that has been tried has led to failures, usually in the Although the formal process of soil correlation goes through direction of far too many separations that are not distinctive. The three steps, problems are flagged as far in advance as possible in decisions are based on judgments of the interactions among the soil order to arrange for the necessary field and map data and characteristics and of the significance of combinations of them comparative studies both within and outside the survey area. to the -scientific and practical purposes of the classification. The correlator checks his judgment against those of other specialists in By taking the process through three stages - field co_rrelation. of related fields who help him. By the time that a soil correlator the area within a State or small group of States, mtermed1ate becomes faced with such responsible decisions, he has already correlation within a large group of States, and final correl~tion been making them under guidance in the field for years. And he within the nationwide system - it is possible to bring many Judg­ has seen the decisions being tested against practical experience. ments to bear on the classification by soil scientists with varying There is the evidence of standing water in the fields; of erosion, of degrees of breadth of experience. This is necessary to be sure that crop yields, of responses to fertilisers, of fhe naiive vegetation, of local conditions and relationships are fully understood and that experience with the use of machinery, and so on through a very the definitions and names are uniform within the national system. long list. He has tested his field judgment of identity, or lack of During this process of evaluating the validity of the classification, it, against laboratory data on samples of the soil horizons. He has many problems arise, partly because th·e soil correlators are tested the units in mapping; and he has seen the maps tested by comparing soils over wide areas. Although they try to develop farmers, land appraisers, engineers and others. Such judgments are standards for the description of the soil in the area of its greatest based on broad experience with both similar and highly contrasting extent decisions there affect the correlation over a wide area. Then soils, not simply with the special situation in a local area. too the redefinition of one soil affects the definitions of all its clo~e relatives. Thus unresolved problems about the proper nomen­ ,Besides these questions, he considers the probable extent of the clature of soils in areas where they are prominent, hold up soil. If only a few small areas of it are expected he establishes a correlations in areas where they are relatively minor, perhaps in variant of an established series, not a new series. a different State or group of States. Through all these steps, Within his assigned area each soil correlator tests his judgment judgments are made among alternatives. against those of his associates in cooperative soil survey work and Probably the most common question put to the soil classifier with other scientists and technicians. Near the margins of his area, is, "How do you know when a soil fits into an established kind and he tests his judgment against those of his colleagues in adjoining when it does not?" No one has a pat answer. With some over­ areas. Finally, the whole system as viewed by all the soil correlators simplification we can say that each time a soil scientist looks at a must fit together consistently. The same or similar kinds of soil soil to identify it, whether he realises it or not, he poses a choice occur in different parts of the country. For example, criteria used between two alternatives. At the level of a detailed soil survey, in the north-eastern part of the country for defining soil series in for example the soil classifier inay choose first between (a) Miami the Bt'own Podzolic group must be consistent with those used for silt loam, a~d (b) not-Miami silt loam. If the answer is not-Miami similar soils in the States of the Pacific Northwest. The same is silt loam, he then sets up another dichotomy, let us say, (a) true for part of the organic soils in the _Lake States, in the north­ St. Clair silt loam, and (b) not-St. Clair silt loam. If the answer east, and in the far western States. Not infrequently the soil corre­ is not-St. Clair, he tries again. If he cannot set up a dichotomy lator must depend primarily on his colleagues in another State or that results in a positive _ name, finally, after he exhausts all group of States for a decision. Although a soil is important in his possibilities, he is forced to establish, at least tentatively, a new assigned area, if the major occurrence is outside of it, he will soil series. need to get his guidelines from those responsible there. Without In going through this logical process, the answers to these longtime planning for such studies, either serious delays or errors questions can be very difficult even for the soil correlator who are inevitable. knows what is already known about the soils throughout the total Then too, many of the kinds . of soils in the United States have range of the occurrence. · been studied more in other countries than in our country. Kinds of Perhaps the three most common questions facing the soil soil common between the United States and Europe have been used correlator are the following: ( 1) When he examines a soil that much longer there than here. By studying this European experience has a combination of characteristics outside the limits of any we improve our judgments on the relatively longtime significance existing defined soil series, how does he know whether to establish of different sets of soil. characteristics. Although important for many a new soil series, to broaden the definition of the soil series most soils in the humid parts of the country, it is of immediate ·significance nearly like the soil in question, or to establish a variant within the to the wet soils ,common between the United States and Western nearest series? (2) How does the soil correlator know when to split Europe. 218 219 We have important areas of Gray-Wooded soils. But larger areas APPENDIX 15 - Soil Profile Records, Including Some New are found in Canada where there has been more experience with American Terms for Horizons and Some Engineering Terms them. Certainly we want to make full use of this Canadian experi­ ence. Illustrations involving a great many countries could be cited. Commonly Used in Soil Descriptions Through exchanges of results and experience better judgments can be formed in soil correlations both here and abroad. The knowledge we get this way, by reading and conversation, is the cheapest that Soil Profile Records we come by. The record of a soil profile contains three essential p~s: the Questions also arise about the level of intensity of predictions that name and classification of the soil; the characters of the site; and the soil correlator should have in mind. For example, in semiarid the description of the profile itself. regions areas of the same kind of soils are so situated in respect to water supplies and to other soils that some areas may be used for dry farming, some for extensive range, and some for irrigation. To have a useful and consistent classification the soil series must be Name and Classification defined in the same way in the three situations. Are they defined In the absence of an established soil name, the tentative name is narrowly enough for farm predictions under irrigation, or in broader given and clearly indica!ed as such ( sef: p. 131): It is inadvisable to terms? In actual practice the soil series arc defined to have predic­ give tentative geographic names to soils of mmor extent such ~ tion value under the intensity of P,ractical dry farming. Differences those mapped during special investigations of small areas; such soils in soil characteristics that are sigmficant to irrigation but not to dry may be referred to as variants of a related type . or simply named farming are pulled out for emphasis as phases. While in the extensive genetically. For classification purposes, the techmcal nomenclature areas soils that respond alike to range management may be com­ is used. bined into undifferentiated mapping units or complexes if their differences are not significant in hydrology and engineering. In many parts of the country a soil may vary in use significantly from extensive woodland to intensive vegetable production. For Characters of the Site series definition the soil correlator would consider combinations of The characters of the site may be summarised as: characteristics on the intensive side of the intermediate point in the t. Exact location. For key profiles, the grid reference is given and range, say intensive general farming or orcharding. the site is marked on a map (see pp. 17-18). The development of interpretations and their application are im­ 2. Topography. Position of the profile in the landscape. Aspect portant tests of the accuracy of soil correlation. But this kind of and slope at the site of the profile (see pp. 28-33). test has to be applied with a great deal of judgment because soils may be alike in terms of one kind of interpretation and very differ­ 3. Drainage, including depth of water table where applicable (see ent in terms of another. For example, in semiarid regions soils have pp. 33=-40). different relative ratings for crop use and for range use; and in 4. Vegetation - of environs, over profile, and assessment of previous humid regions the ratings are unlike for crop use and forest use. native cover (see pp. 47-49). All sorts of interpretations need to be considered. 5. Parent material, parent rock (actual and proximate), and D The soil classifier. must distinguish between soils having signifi­ layers (see pp. 19- 28). cantly unlike characteristics even though he cannot see their signifi­ cance in current interpretations. Equally, he must guard against 6. Climate, including amount of rainfall (inches) and. its distribu­ unneeded separations of soils based on insignificant differences. In tion (rain days) per annum, actual or estimated (see carrying on soil survey work we are commonly dealing with many pp.40-46). soils about which little is known and about which we have little 7. Land use and other relevant details (see pp. 57-58). specific recorded experience. In deciding about proper definitions of these soils and their place in the classification, we must be guided by the results of the more abundant research and experience on soils elsewhere, perhaps far away, where the effects of different Description of the Profile characteristics have been measured and their influence assessed. The description of the profi!e !tself may be. arran_ged conveniently This is a very difficult matter for judgment. After all, we cannot in three sections: ( 1) a descnption of the soil horizons of a pedon consider all soil characteristics in an extreme sense. No doubt a (pp. 16. 69); (2) the relationship to other pe_dons (p. 1~6); and man could spend his whole life working on one handful of soil. (3) explanatory notes. The first and seco!ld secti~ns ~e dehb~rately Our judgments must always be based on the relevant characteristics objective with the exception of the honzon design~hons which . at that determine the behaviour of the soil in both natural and cultural the present stage of kno_wledge !en~ to ~e i~terpret~tive. The third environments. section need not be entirely obJecttve smce it consists of person~! impressions and explanatory interpretations designed to help m understanding the objective record. 220 221 A convenient order for describing the characters of each soil Vegetation: Of site- Manuka, spanish heath, gorse, Pinus horizon is: radiata; Over profile- Manuka, gorse; Previous native. cover­ 1. Horizon designation; Hard beech (Nothofagus truncata). 2. Thickness; Parent Material: Deeply weathered greywacke. 3. Dominant colour; Climate: Rainfall, 50·6 in.; Rain days, 161; Mean temperature, 4. Texture, including stoniness, etc.; 5. Colour patterns, including mottling; 54·6°F. 6. Consistence and porosity, including compaction and cementa­ Land Use: Experimental regenerating native forest catchment. tion; Hills cleared 1850-60 for pastoral farming but pastures reverted 7. Structure, including compound and mixed structures, and to gorse and manuka which have been periodically burned characters of peds, including their consistence, coatings, interrupting regeneration to forest. Nearby pastures respond well and other variations; · to molybdic superphosphate. 8. Special formations such as pans, nodules, salt efflorescences, Profile: and infilled tunnels; rock fragments, etc.; 9. Biological observations such as abundance and character of 0 1 ¼in. Dry litter - leaves and twigs from manuka, living and dead roots, relation to root growth, worms, spanish heath, and gorse, insects, burrows, etc.; 02 ½in. very dark brown (l0YR 2/2) decomposed litter 10. Boundary, including distinctness and shape; with some recognisable plant fragments; friable; 11. Any diagnostic chemical observations such as pH. weakly developed fine and medium granular and crumb structure, many distinct elongated casts The · order is not invariable but depends partly upon ease of (5 mm); many roots, some fungal hyphae; sharp description and the relative impOTtance of the various characters; some field men, for example, prefer to describe mottling after boundary, structure, or to place Munsell notations at the end of the horizon A11 2in. very dark greyish brown (l0YR 3/2-3/4) clay description. Thickness may be expressed as such or, with simple loam; friable; weakly to moderately developed profiles, in terms of depth from the surface. In the explanatory medium granular structure with some coarse cast notes, personal impressions of the origin of the characters of the granules; many roots; indistinct boundary, profile are useful because the observer sees the profile in its en­ A12 3 in. very dark greyish brown (l0YR 3/2-3/4) clay vironment whereas those interpreting the written record do not. loam; firm; weakly developed medium and fine Descriptions of soil profiles vary in detail according to the nut structure with some coarse cast granules; purpose of the record. Detailed precise descriptions are required many roots; sharp irregular boundary, for some special investigations and should be made for modal B21 7 in. yellowish brown (lOYR 5/6-5/8) clay; very firm; and other key profiles .but they are time consuming and for many moderately developed coarse nut structure with purposes are neither necessary nor justified. · In publications for pale yellowish brown coatings on peels, some the general reader, very detailed descriptions of soil profiles are coarse prisms with dark greyish brown clay loam best kept to a technical section. in vertical cracks; few fine white and strong Since in ordinary descriptions some characters may be omitted brown mottles in upper 2-3 in.; many roots; in­ in the interests of brevity, a character that is not mentioned distinct boundary, cannot safely be presumed absent. For this reason a character is B22 8 in. brownish yellow (l0YR 6/6) clay; firm; moder- recorded as absent when its absence would not be expected. Thus ately developed medium blocky structure with if stones are reco:rded in the A horizon but are not present in pale yellowish brown filmy coating on peels, the B their absence from the B horizon is stated. weakly developed coarse prisms in places; few fine reddish yellow mottles; few roots; indistinct Example of Profile Record boundary, Ba 8 in. similar to B22 but structure is weakly developed, The following is an example of an ordinary technical description: a few small fragments of red clay (¼-1 in. diam.) Soil: Taita clay loam. are present, and the boundary is diffuse, qassification: Strongly enleached moderately clay illuvial sur­ C1 26+ in. brownish yellow and red (2·5YR 5/6) stony clay, fulvic soil from strongly argillised greywacke. with red elongated coarse mottles in inclined Location: Taita Experimental Station, 6 ch 'S of the Taita veins; firm; weakly developed coarse blocky Reservoir. In native forest catchment, 10 yd north of boundary structure. The stones are pieces of weathered between paddocks 3 and 4. A profile from reference pit for 1962 International Soil Conference. N160/508347. greywacke. Topography: pn northern side of narrow ridge top; altitude, NOTES-Upper horizons vary in thickness - 01 (¼-¾ in.), Au 370 ft; slope, 16 . (¾-2 in.), and A12 (3-5 in.). Mottles in B21 are absent from 70 to Drainage: Moderately well drained. 75 per cent .of pedon. The blocks of the C1 horizon tend to ·split 222 223 into thick vertical plates. Hard fresh greywacke occurs at a !evel 200 ft below the profile. A moderately regressive profile; associated Subsurface Horizons more weakly regressive profiles on the flatter areas ~?OW a str~nger Most of the horizons described, but not all, are generally accepted prismatic structure with more pronounced dark coaLmgs on pnsms, as B horizons. - and in places, a shallow A2 honzon. . An argillic horizon is an illuvial horizon in which silicate The clay loam in cracks in the B21 appears to be m!llled from clays"have accumulated to a significant extent. above. The pale coatings on peds appear to be clay skms for~ed An agrie horizon is an illuvial horizon of clay and organic by illuviation. Th~ high clay content and the presence of . rt:d matter formed under cultivation. Commonly it is immediately weathering" in the B3 and C1 indicate that the present soil 1s below a plough layer. formed in an old soil which was developed ~.md~r a former warm strongly argill1sing climate; the red mottled vems m the C1 resemble A natrie horizon is another special kind of argillic horizon a fossil gammate pattern. with prismatic or columnar structure, and with more than 15 per cent saturation with exchangeable sodium. A less detailed description of the same profile, more suitable for the general reader, is: A spodic horizon is an illuvia) accumulation of fre~ sesquioxides commonly accompanied by organic matter. The iron-humus pan Ai 5 in. very dark greyish brown clay loa~; firm; weakly of a podzol is spodic. developed medium nut structure with som_e coarse cast granules; many roots; sharp irregular A eambie horizon is commonly a (B) horizon. It is not strongly boundary, argillised and is insufficiently illuviated to be classed as argillic 15 in. yellowish brown clay; very firm; moderately or spodic. In clayey materials it may have well developed developed coarse nut to medium b_locky structu!es structure. with continuous clay skins, and with dark gre}'lsh An oxie horizon is a strongly argillised horizon containing brown clay loam in vertical cracks; few fine abundant free sesquioxides, usually comprising more than 12 per reddish yellow mottles; many to few roots; cent of the clay fraction. indistinct boundary, C on brownish yellow and red stony clay. The stones are pieces of weathered greywacke. Other Horizons An a/hie horizon is a bleached horizon, from which clay and free iron oxides have been removed or in which they have been so segregated that the colour is determined by the primary sand Some New American Terms for Horizons or silt particles. The A2 horizon of a podzol and the subsurface The terms introduced for diagnostic horizons in the new so~l eluvial horizons due to perched ground-water moving over an classification of the United States are useful for general soil impervious layer are examples of albic horizons. description. Their meaning !S bri_efly in~icat~d here,. and complete Calcic, gypsie, and salic are terms applied to horizons more definitions are to be found m Soil Class1fieation (Soil Survey Staff, than 6 in. · thick which are enriched respectively with calcium 1960, pp. 32-64). carbonate, gypsum, or salt. Surface Horizans A horizon that forms at the sur_face is named _an epipedon. The term is not quite synonymous with _the A horizon as generally accepted since the epipedon may mclude part or all of an Some Engineering Terms Commonly Used in Soil illuvial horizon if the darkenii:ig by the orgamc matter extends Descriptions from the surface into or through it. A mo/lie epipedon is a thick dark surface layer with. moderate By R. D. Northey, Soil Bureau. to _strong structure, with at least 1 J?Cr cent ?rgamc matter throughout, and with a narrow carbon/mtrogen ratio (P or le~). In amplifying soil descriptions, some engineering terms are com­ monly misused. To clarify them, the following notes have been It has a base saturation of more than 50 per cent, with calcmm prepared. as the dominant metallic cation. . An umbrie epipedon is similar but has lower base saturation, The sensitivity of soil material is the ratio of its natural strength a wider carbon/ nitrogen ratio, or both. The d~rk surface ~ayers to the strength when it is completely remoulded at the same water of some yellow-brown loams and acid gley soils are umbnc. content: · Soil material is said to be sensitive if it loses a substantial A histie epipedon is a thin peaty surface horizon, normally proportion of its strength when remoulded. The term is normally less than 12 in. thick. restricted to plastic materials. To test for this property in the field, a clod of moist soil material may be divided into two pieces and, after An oehric epipedon is too light in colou_r, or too: low in .o~ganic one has been completely remoulded, the strength of each is ass\;ssed matter, or too -thin to be classed as molhc, umbnc, or h1St1c. by shearing between the fingers. 224 The dilatancy, the tendency for a mass composed of discrete part­ APPENDIX 16 - Summary of Main Criteria for Soil Profile icles to expand when deformed, is an identifying characteristic of Descriptions · sands and silts. If a pat of moist silt on the palm of the hand is shaken vigorously by bumping, its surface becomes glossy as water is Order of Profile Descriptions _expelled. Application of pressure causes the surface to . dull and lighten in colour as the· water drains back into the specimen. 1. Depth or thickness of horizon; 2. Colour; 3. Texture· 4. Con­ sistence and porosity; 5. Structure; 6. Roots, etc.; 7. Kind ~f bound- The liquid and plastic limits are the water contents defining the ary. . upper and lower limits of the plastic range in remoulded soil mater­ ials; that is, the range of moisture content within which the soil is Repeat for each horizon and record location, position in landscape plastic. Materials of low liquid' limit contain little active colloidal and slope, etc., vegetation, parent material, together with climate, material either mineral or organic. Silts have a narrow plastic land use, etc. range so that little additional water is required to change them from a friable solid to the liquid state. Colour Patterns Mottles Gammate For"'8 Abundance ( %) Size (mm) Contrast Shape Few, <2 Fine, <5 ·Faint Subgammatc Many, 2-20 Medium, 5-15 Distinct Gammatc Abundant, > 20 Coarse, >15 Prominent Net-gammate Profuse, c. 100

Consistence Dry Moist Wet Cementation Loose Loose Nonsticky Nonplastic Weakly Soft Very friable Slightly sticky Slightly plastic cemented Slightly hard Friable Sticky Plastic Strongly Hard Firm Very sticky Very plastic cemented Very hard Very firm lndurated Extremely hard Extremely firm

Structure Grade of development Structureless (massive, single grain), weakly developed, moderately developed., strongly developed Shape and vize of aggregates (mm) Platy Prismatic and Blocky and Granular and Columnar Nut Crumb V, thin, 10 V. coarse, > 100 V. coarse, > 50 V. coarse, > 10 Stoniness With stones < 7 per cent, stony 7 - 30 per cent, very stony > 30 per cent.

Horizon Boundaries Sharp, almost a line; distinct < 1 in. (or < 10 per cent of horizon if thin); indistinct 1-3 in.; diffuse > 3 in. · Approximate Equivalents mm. 5 10 15 20 50 100 in. 0·2 0·4 0·6 0·8 2 4 226 227 COTTON, C. A. 1948: "Landscape." Whitcombe and Tombs Ltd, References Wellington. 509 pp. --- 1944: "Volcanoes as Landscape Forms". Whitcombe and Tombs Ltd. Wellington. 415 pp. AGUILERA, N. H.; JACKSON, M. L. 1953: Iron Oxide Removal from -- ; TE PuNGA, M. T. 1955: Solifluxion and Periglacially Soils and Clays. Proc. Soil Sci. Soc. Amer. 17: 359-69. Modified Landforms at Wellington, New Zealand. Trans. roy. ALLAN, H. H. 1940: A Handbook of the Naturalised Flora of Soc. N.Z. 82: 1001-31. New Zealand. N.Z. Dep. sci. industr. Res. Bull. 83. 344 pp. CowIE, J. D.; SMITII, B. A. J. 1958: Soils and Agriculture of ATKINSON, J. D. 1939: VII. Fruitgrowing. In NZ. Dep. sci. industr. Oroua Downs, Taikorea, and Glen Oroua Districts, Manawatu Res. 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Soil Sci. 72: of Organic Soils and Availabilities of 12 Plant Nutrients .. Soil Sci. 1-19. 92: 177-82. IGNATIEFF, V.; PAGE, H. J. 1958: Efficient Use of Fertilisers. F.A.O. LUNDBLAD, K. 1944: [Terminology for Plant Residues and Organo­ Agric. Studies No. 43. Rome. 355 _pp. genic Soils. Peat, Gyttja, and Dy.] Svenska Vall-o. Mossk-Foren. Kvartalsskr. 6: 197-204. JACKS, G. V.; TAVERNIER, R.; B0ALOI, D. H. 1960: "Multilingual MADDEN, E. A. 1940: The Grasslands of the North Island of iNew Vocabulary of Soil Science." 2nd ed. (revised). F.A.O. Rome. 430 pp. Zealand. N .Z. Dep. sci. industr. Res. Bull. 79. 45 pp. McCALLUM, G. J. 1955: Correction for the Effect of Cosmic JoFFE, J. S. 1949: "Pedology." 2nd ed. Somerset Press. Inc. New Radiation on Field Measurements of the Radioactivity of Soils. Brunswick, New Jersey. 662 pp. N .Z. J. Sci. Tech. B37: 172-8. 230 McDONALD, D. C. 1968: Classification of Soils on a Moisture Basis. In SoIL CoNSERVATION SERVICE, 1954: A Manual on Conservation of Soils of New Zealand. N.Z. Dep. sci. industr. Res. Bull. 26 (1).142 pp. Soil :and Water. U.S. Dep. Agric. Hdbk. No. 61. 208 pp. McNEUR, A. J. 1956: Grass Identification System Using Punched SorL SURVEY STAFF 1951*: Soil Survey Manual. U.S. Dep. of Agric. Cards. Grasslands Divn., N.Z. Dep. sci. industr. Res. Palmerston Hndbk. No. 18. 503 pp. North. --- ~1960: Soil Classification. A Comprehensive System. 7th METSON, A. J. 1956: Methods of Chemical Analysis for Soil Survey approx. Soil Conservation Service, U.S. Dep. Agric. ( Washing­ Samples. N.Z. Soil Bur. Bull. 12. 208 pp. ton). 265 pp. MINISTRY oF WORKS 1961: Provisional Standard for Empirical STEVENSON, G. 1959: "A Book of Ferns." 2nd ed. (revised and en­ Estimation of Flood Discharges. Tech. Memo. 61 (2nd Rev.). larged). Paul's Book Arcade. Hamilton. 168 pp. Wellington. SuOOATE, R. P. 1960: Time-Stratigraphic Subdivision of the Quatern­ NrKIFOROFF, C. C. 1941: Morphological Classification of Soil ary as Viewed from New Zealand. Quaternaria, 5. 13 pp. Structure. So-ii Sci. 52: 193-207. SumERLAND, N. W. 1953: Soil Conservation Survey of the Porewa --1959: Reappraisal of the Soil. Science, 129: 186-96. Stream Catchment, Rangitikei, New Zealand. Min. of Works NORTON, E. A. 1939: Soil Conservation Survey Handbook. U.S. Report. Palmerston North. 46 pp. Dep. Agric. Misc. Pub/. '352. 40 pp. TAYLOR, N. H. 1935: Water Supplies of Farms and Dairy Factories PHILLIPS, R. E.; JENSEN, C. R.; KIRKHAM, D. 1960: Use of Radia­ in Hamilton Basin and Hauraki Lowland. N.Z. Dep. sci. industr. tion Equipment for Plow-Layer Density and Moisture. Soil Sci. Res. Bull. 48. 58 pp. 89: 2-7. --- 1949: Soil Survey and Classification in New Zealand. Proc. POLYNOV, B. B.; MIKLASZEWSKI, S.; 8cHLACHT, K.; PRESCOTT, J. A. 7th Pac. Sci. Congr. 6: 103-13. 1930: Methods of Taking Profiles. Imp. Bur. Soil Sci. Tech. Soil --- 1952: Pedology as an Aid in Animal Research. Aust. vet. J. Comm. No. 7. 8 pp. 28: 183-9. POOLE, A. L.; ADAMS, NANCY M. 1963: "Trees and Shrubs of New --- 1955: The Role of Soil Science in New Zealand Problems. Zealand." Govt. Printer. Wellington. Trans. roy. Soc. N.Z. 82: 961-72. RAESIDE, J. D. 1956: Yellow-grey Eart~ of South Island, New --- 1958: Soil Science and New Zealand Prehistory. (Proc. N.Z. Zealand: an Example of Polygenesis in Soil Development. V/8 Arch. Soc.) N.Z. Sci. Rev. 16: 71-79. Cong. Sci. Sol Paris. Rapports Comm. V, Vol. E: 665-71. ---; CUNNINGHAM, I. J.; DAVIES, E. B. 1956: Soil Type in RAMSBOTIOM, J. 1953: "Mushrooms and Toadstools. A Study of Relation to Mineral Deficiencies. Proc. 7th Int. G1assl. Con/. pp. the Activities of Fungi." Collins. London. 306 pp. 357-67. RussELL, Sir E. J. 1958: "Soil Conditions and Plant Growth." 8th ---; DIXON, J. K.; POHLEN, I. J. 1955: Current Research in Soils ed. (revised iby E. W. Russell). Longmans, Green and Co. and Fertilisers. Proc. N.Z. Inst. Agric. Sci. pp. 34-39. London. 635 pp. ---; POHLEN, I. J. 1959: Soils and Land Use. In A Descriptive -- 1959: "The World of the Soil." Collins. London. 237 pp. Atlas of New Zealand (ed. by A. H. McLintock): 28-33, Maps SAXBY, S. H. 1956: Pasture Production ,in New Zealand. N.Z. Dep. 12 and 13. Govt. Printer. Wellington. Agric. Bull. 250. 203 pp. ---; --- 1968: The Classification of New Zealand Soils. In Soils of Scorr. R. H. 1959: . Land Utilization. In A Descriptive Atlas of New Zealand. N.Z. Dep. sci. industr. Res. Bull. 26 (1). 142 pp. New Zealand (ed. by A. H. McLintock): Maps 20 and 21. Govt. Printer. Wellington. ---; SulHERLAND, C. F. 1936: Field Work in North Auckland. SHARPE. C. F. S. 1938: "-Landslides and Related Phenomena." Annu. Rep. N.Z. Dep. sci. industr. Res.: 47-49. Columbia University Press. New York. 137 pp. TE PuNGA, M. T. 1954: Late Pleistocene Buckshot Gravels from SMrrn, H. W.; MOODIE, C. D. 1947: The Collection and Preservation Western Wellington, New Zealand. N.Z. J. Sci. Tech. B36: 1-13. of Soil Profiles. Soil Sci. 64: 61-9. THORNTHWAITE, C. W. 1948: An Approach towards a Rational ------1952: The Collection and P!feservation of Soil Profiles Classification of Climate. Geog. Rev. 38: 55-94. II. Soil Sci. 73: 243-248. Tooo, J. E. 1903: Concretions and their Geological Effects. Bull. SorL CONSERVATION AND RIVE.RS CoNTROL CouNCIL, 1953: Hydrology Geo/. Soc. Amer. 14: 353-60. Annual. Wellington. 86 pp. TRUOG, E. 1946: Soil Reaction Influence on Availability of Plant 1961a: Handbook of Hydrological Procedures: Pro­ Nutrients. Proc. Soil Sci. Soc. Amer. 11: 305- 8. visional Procedure No. 8, Base Flow Recession Curves. Welling­ ton. 5 pp. UNITED STATES MANUAL or UNITED STATES "SorL SURVEY MANUAL" 1951: See SorL SURVEY STAFF 1951. 1961b: Handbook of Hydrological Procedures: Pro­ visional Procedure No. 9, Suspended Sediment Sampling-Ap­ •In this handbook the United Stales Soil Survey Manual (Soil Survey Staff, 1951) is frequ_e!lllY Quoted as the United· States Manual in order to avoid cumbersome proximate Method. Wellington. 3 pp. repeuuon of the complete reference. VAN BAVEL, C. H. M. 1961: Neutron Measurement of Surface Soil Moisture. I. Geophys. Res. 66: 4193-8. Index ~; UNDERWOOD, N.; SwANSON, R. W. 1956: Soil Moisture NOTE-To shorten this index many subjects have been listed in the Measurement by Neutron Moderation. Soil Sci ..82: 29-41. "soil" section only, e.g., "colour" is indexed as "soil colour". WAKSMAN, S. A.; STEVENS, K. R. 1930: A Critical Study of the A horizgn, 71 B horizon, 72 · Methods for Determining the Nature and Abundance of Soil Abbreviations, textural, 176 Bacteria, 52 Organic Matter. Soil Sci. 30: 97-116. Absorbent soils, 206 Basal furm, 157- 9 Accumulations Base flow recession curves, 207 WELLS, N. 1956: Soil Studies using Sweet Vernal to assess Element air-borne, 165 Base map, 145 Availability: Part II. Molybdate ion fixation in New Zealand Category III, 157, 162, 165 Base saturationJ 25, 169, 113 Soils. N.Z. I. Sci. Tech. 37: 482- 502. drift regime, 156, 165-6 Basement zones, 160 --- 1960: Total Elements in Topsoils from Igneous Rocks: lodic, 165 Bases, 22, 102, 213 an Extension of Geochemistry. I. Soil Sci. 11: 409-24. nodules, 107 Basin peats, 119- 21, 165 WHITESIDE, E. P. 1959: A Proposed System of Genetic Soil-Horizon nomenclature Category IV, Bioturbic soils, 166 Designations. Soils and Fert. 22: 1- 8. 168 Bleaching, 52 platic, 165 Bog, 121, 165 WILDE, ~- A. 1946: "Forest Soils and Forest Growth." Chronica soluble salts, 112 Boron, 23--4 Botamca Co. Massachusetts. 241 pp. special, 103- 13 Boulders, 88, 149 WRIGITT, A. C. S.; MILLER, R. B. 1952: Soils of South-West Fiord­ subscripts, 73 Brown granular clays, 156, 172 land. N.Z. Soil Bur. Bull. 7. 35 pp. water-borne, 165 Brown-grey earths, 155, 158, 172 Accumulative soils, 29, 53, 166 Buffered soils, 102 ---; RICHARDS, J.; LoBB, W. R.; MILLER, R. B. 1951: Soils organic matter, 119, 126 Buried soils, 53, 74, 168 and their Utilisation, Green Island-Kaitangata District. N.Z. Acidic rocks, 26, 155 "Buttery" horizons, 110 Soil Bur. Bull. 6. 36 pp. Ad-, 160 Burrows, 50-1 ZMYSLOWSKA, S.; WILGAIN. S. 1961: Research on Natural Radio­ Aerobic activity, 114 activity of Soils -Distribution of o::-Radioactivity in Soil Af-, 162 Profiles. Nukleonika, 6: 813- 26. Age of site, soil, 17, 53-7, 107 Agric horizon, 225 C horizon, 72 Albie horizon, 225 C/N ratio, 115, 131, 213 Alkali soils, 112 ' Calcic horizon, 225 Allophane, 25, 192 Calcite growths, 112, 181 . Alpine zone, 44, 160- 1 Caliche, 109 Altitudinal zones, 44, 155, 157, Cambric horizon, 225 160- 1 Capability. See Land capability. Aluminium, 71, 72, 81, 104-5 Capillary fringe, 33 Alvie soils, 164 Carbon, organic, 212 Amadic soils, 164 Casts, 51, 179 American classification, 144, 224 Catalogue of maps, 177 Amo-, 162 Catchment measurements, 205-7, Amorphous clays, 25, 162, 192 177 Anaerobic processes, 80, 114, Categories of classification, 157 124 Category I, 157- 9 Angles of slope, 175 Category II, 160- 2 Animals, 49- 52, 179- 80 Category III, 162-8 Antarctic zone, 160 Category IV, 168 Antecedent, 56, 74 Category V, 140, 169 Argillic horizon, 225 Category VI, 169 Argillisation, 24-8 Category VII, 169- 71 conditioning, 156 Cation exchange capacity, 213 conformable, 163, 164 Cementation, 91 - 3, 107- 9 grade, 24, 162- 5 Chemical analyses, ratings, J30, kind, 25- 7, 162, 192 212-4 pre-argillised, 27 Chemical elements in rocks, antecedent, 56 23-4 Ash beds, 111, 186 Chitinous residues, 179 Avalanches, debris, 31, 59 Chroma Munsell, 76 Azonal, 172-3 Classification. See Soil class. Clays, 24-6, 162-4 E-, 160 accumulation, illuviation, 73, Earthflows, 62 91, 104. 111 Earthworms, 50-1 classification, 192 Easyland soils, 31 dispersion, 111 Effective moisture, 44-6, 160, sensitive, 25, 225 167 skins (films), 111. 180 Efflorescences, 112 swelling, 111 Egg-cup podzols, 27, 48 Claypans, 110-1 El-, elad-, elde-, ele-, elpro-, 160 Climate, 17, 40-4 Eluvial, 71, 73, 180 Clinic soils, 164-5, 167 Emerged peats, 126 a Clod, 93 Energy status, 160-2 Clovers, 196-204 Engineering terms, 225--6 Co-, 167 Enleaching, 48, 169-70 Coastal marsh, 112-3, 121 Enriched residuals, 105--6 Cobalt, 23 Environment and soils, 56 "Coffee rock", 108 Epigenetic, 56 Colluvial, 157 Equivalent map scales, 175--6 Compact, 91, 107-9 Equivalent measurements, 175 Composite soil, 168 Epipedon, 224 Compound slopes, 30 Erosion, 58--65, 156-7, 205 Concave basin peats, 119-21 frost heave, 42 Concretions, 36, 104-7 natural. 29 Conditioning, 156 phase, 138 Photo, C. S. Harris Conformably argillised, 163 run-off, 36-7 Conglomerates, 184 Evaporation and drainage, 35 Consistence, 25--6, 89-93 Evapotranspiration, 44 Constructed universal, 134 Eutrophic peats, 119 Convex basin peats, 119--20 Extended suites, 152 Coprogenic moder, 115, 117-8 External soil drainage, 36-7 "Cropstones", 51, 108 Crystalline layer silicates, oxides, 162, 192 Cultivated layer, 71, 73 "Cutans", 110, 180-1 F horizon, 71, 115-8 b Faecal pellets, 115, 179 Farming and soil classes, 151 Faunal excrement, remains, 179 D layers, 72 Fen peats, 127 De-, 160 Ferns, 194 Dehydration, 106 Ferromagnetic oxides, 183 Density. See Soil density. Fcrruginous latosols, humic, 106 Depth of horizons, 74, 128-9 Ferruginous tubles, 106 Detailed surveys, 133, 146, 149 Fertility. See Soil Fertility. Diagnostic horizons, 224-5 Field capacity, 38-9, 44--6 Dicotylous, 118 Fissures, 180 Dilatancy, 225 Fixation - molybdenum, phos- Discontinuities, lithologic, 74 phorus. 23 Photo, R. Julian District surveys, 133, 146, 149 Flood potential, 205--6 p Drainage, 35-40, 80 Flow erosion, 61-2 I· -I drained phases, 138 Fluffiness, 25, 89 PLATE I. Value of the pedon concept. (a) Soil section showing sequences, 151 Flushing, 34. 105, 108 relatively uniform horizons. (b) Section showing roughly cyclic Drift, 19-20, 156, 185 Forest, 47, 58 variations; p. indicates the length of the profi_le cycle, half of Duff, 115 Formations, special, 103-13 which is the length of the pedon. Auger bonngs alone would Dynamic system, 13-4 "Fossil gley", 81 indicate a single soil in (a) and many soils in (b). See p. 16. Dy peat, 122-3 Fossil pollens, 55 a a

I in.-----~

b b

PLATE 3. "Coffee rock" pans in soils from One Tree Point, PLATE 2. (a) Coarse mottle in_ Parau clay due to gleyin•g around Whangarei Co. (a) Humus iron pan with pronounced mottling old kaun peg root; the root -1s 2 ft long. See p. 80. (b) Vesicular around old root traces. (b) Humus pan with no mottling around pores in topsoil of a brown-grey earth. Seep. 98. old roots - the white specks are bleached sand grains, the horizon being illuvial for humus hut not necessarily for other mobile a

b b

.,_ I in. ------t l'hoto, B. C. Barratt

PLATE 4. (a) Crumb structure. (b) Granular structure with some PLATE . 5. (a) Platy structure - in a topsoi1. (b) Blocky structure crum·b. In topsoils. Insets to same scale. showing aggregates fitting together when wet --in a subsoil a a

b b

Photos, R. Julian t--- I in. ---i Photo, R. Julian

PLATE 6. Nut (su'bangular blocky) structure in topsoil. (a) Individ~al PLATE 7. (a) Prismatic structure. (b) Composite structure in top-soil, com­ aggregates. (b) Showing aggregates :fitting together when moist; pound structure (prismatic breaking to blocky) in subsoil. the granules on right indicate some composite structure. Fossil soils Gully erosion, 62 buried soils, 74 Gumlands, 56 fragipans and climate, 109 Gypsic horizon, 225 volcanic ash beds, 186 "Gypsum butterflies", 181 Fragipans, 73, 82, 109, 158, 168 Gyttja peat, 122-3 Freezing ... and thawing, 42 Friability, 25, 91 71, 115, 117 From, 68 H horizon, Frost heave, 42 Halloysite, 26, 104, 106 Frigic soils, 166 Hand lens, 178- 82 Frozen soil, 73 Hill soils, 141- 2 a Horizons. See Soil horizons. Fulvic soils, 164, 192 Hue, Munsell, 76 Fulviform soils, 158, 162 Humic, 87 Fungi, 52, 178, 180 Humic ferruginous latosols, 106 Humification, 124-6 G horizon, 73 Hummocks, 33 Gammate, 81- 2, 109, 158 Humus, 113- 9 Gasteroliths, 51, 108 iron horizons, 81 Gelic soils, 166 microstructure, 180 Genetic classification, 134, 141, mineralisation, 124 155- 174 mull earth, 115 Genetic names, 170-2 stains, 180 Geographic environment, 152 Hydrological, 205- 7 G~ographic name, 139 Hydrous, 46 Geology, 144 Hydrous podic soil, 167 Geomorphology, 29, 59 Hygrous, 45 Gibbsite, 26, 105, 192 Glaciation, 53, 107 -i-, 167- 8 Gley podzols, 108, 167, 172-3 -ic, 157, 165 Gley soils, 96, 105, 110, 155, 158 -iform, 157- 8 Gleyed colour patterns, 34, 80-1 Igneous rocks, 26, 184-5 Gleyed recent soils, 126 Illimerisation, 110, 156, 168 Gleyed soils, 80, 107, 159 Illite, 25, 192 Gleying, 34, 80-1 Illuvial, 110- 1, 168, 170-1 b G horizon, 73 Immature, 68 gammate, 82 Indigenous vegetation, 47, 193-5 humus-iron horizon, 34-5, 81 Indurated, 93, 110 internal soil drainage, 38 Infilled tunnels, 111 manganese availability, 23 Infiltration-vegetation, 206 micro-organisms, 80, 106 foherited characters, 22, 77, 152 Grasses, 196- 204 Intergrades. See Soil intergrades. Grassland farming, 47, 150- 1," Internal drainage, 38-9 196 Intrazonal, 120, 172-3 Gravelly, 88 Iron Gravels and covering silts, 185 accumulation, 72-3, 108, 159 Grey colours, 80 cementation, 91 Grid reference, 18, 177 clays, 87 Ground water, 33-4 colours, 77 madentiforJ1 soils, 159 gammation, 81 pans, ll)is latosols, 81 --'-3-.-J4 ~ o______z Photo N. H. Taylor pe~~. 124, 126 leaching, 71 .:;a)inity, 112 micro-organisms, 106 soil colour, 77, 80 nodules, 103- 7 PLATE 8. (a) Buried soils, with prominent fragipans- in subhumid See also Water. "Ironstone" soils, 159 district near Timaru. See p. 109. (b) Tunnels and crevices in Ground-water podzol, 56, 108, Irrigation, 35, 39, 121, 147 Tongariro andesitic ash, filled from above by Taupo rhyolitic 17.i Isohyet, 41 pumice. See p. 111. 237 Jarrett auger, 129 Mapping, 133-50 Ombrogenous, 119 Ped, 26, 93-(j Marine marsh, 121 On, 68, 169 corrosion, 180 Mass movement, 59 Organic matter, 71, 113-9 residual, 96 Mature, 68, 107 gleying, 80 Pedon, 16, 134 Kaolinitic, 26, 192 Measurements, equivalent, 175 humification, 124 soil profile, 16, 66 Key to grasses, clovers, 200-4 Medial, 134 humus 113 modal, 136 Krotovinas, 111 Median, 33, 140-1 pans, 108 Pedosphere, 13 Melanisation, 116, 166, 171 profile, 115 Pellets. See Faecal. Mellow, 25, 89 rating, 212 Peneplain, pedologic, 57 Mesophytic, 118, regime, 156 Per-, 161 L horizon, 71 Mesotrophic, 119, 127 texture, 87 Periglacial, 42, 53 Lahars, 62 Microclimate, 41 Organic soils, 22, 119, 126-8, 165 Permafrost, 166 Land capability, 64-5, 208-9 Micro-organisms, 51- 2, 80, 106, intergrades, 165 pH, 100-3 Land form, 29, 32 124 Organiform Soils, 159, 162, 165 Phase, soil, 138, 167, 173 Land slope, 30-3 Micropores, 180 Organisms, 17, 46-52, 166 Phosphorus, 23, 212 angles of, % grades, 175 Microrelief, 33 Otorohanga silt loam, 173 Phytoliths, 49 hydrology, 205 Microscope. 20, 178-82 -ous, 157 Plants, 44, 46-9, 196-204 oversteepened, 31, 59 Mineral grains, 181-2 Over, 68 growth, 13, t 02, 144, 147 phases, 138 Mineralisation, 124 Oxadic soils, 164 indicators, 50 soil map, 148 Modal, 134 Oxi-, 162 remains, 178-9 Land use, 28, 29, 33, 41, 47, Moder, 115, 117 Oxic horizon, 225 roots (q.v.), 179-80 57-8, 146-8 , Mole drains, 110 See also Vegetation. Laterisation, 22 Molybdenum, 23, 24 Plasma, soil, 180 Latiform, 159 Montmorillonite, 26, 192 Plastic range, 226 Latitudinal zones, 44, 161 Mor, 115 Plasticity, 22, 25-6, 90 Latosol, 81, 106, 156 Moroid organic profile, 115--7, Palliform, 158 Platic soils, 165 Leaching, 23, 49, 77, 169 126 Pans, 29, 34, 36, 107-9 Plutonic, 184 A2 horizon, 71 Mottling, 78-80, 82 Parent material, 19-28, 126, 169 Podiform soils, 159, 167-8, conditioning, 156 hand lens, 180 C horizon, 72 172-3 gammate horizons, 81 micro-organisms, 52 discontinuities, 74 Podzolisation, 22 residues, 29, 77 water table, 34 old soil, 27 acid leaching, 48 Lens, hand, 178-82 Mudflows, 62 peat, 22, 119 intensity, 55 Lessivage, 111 Mull earth, 115, 118 soil colour, 77 Podzols, 167- 8, 172-3 Liesegang, 106 Mulloid oganic profile, 115, 117 soil suites, 151- 2 A~ horizon, 97 Lignin, 113, 120, 124 Munsell Chart, 76, 178 Solifluction, 42, 44 albic horizon, 225 Liquid limit, 226 Mycelium, 52, 178 Parent rock, 19-28 antecedent, 56 Lithic soils, 165-6 Mycogenic moder, 115, 117 chemical elements, 23-4 clay pans, 110 Lithochromic, 77 Mycorrhiza, 52 classification, 27, 184- 5 colour, 77 Lithologic discontinuities, 74 National grid, 177 composition, 26 "egg-cup", 27, 48 Lithosols, 39 N atric horizon, 225 colour, 77 epigenetic, 56 Litter, 48, 50, 71, 113 New Zealand sector, 44, 155 D layers, 72 fragipan, 109 Lodic soils, 165 Nickel, 23 proximate, 21, 72, 131 hydrous, hygrous, 46 Loess, 21, 29, 82, 185 Nigriform, 159 radioactivity, 24, 188-9 iron concretions, l 05 Lowland phase, 44, 160 Nitrogen, 213 soi] characters, 22-4, 151-2 iron pan, 108 Luvic soils, 165, 168 Nitrogen-fixing bacteria, 52 soil suites, 151-4 kauri, 27, 48, 56 Noduies, 2~, 103-7, 181 Particle size, 82-3, 88 02 horizon, 115 age of soil, 5 5 Pastures, 196-200 obsolete, 56 significance, 107 epigenetic effects, 56 organic matter in B, 118 Madentiform, 159 Normal site, 28, 173 organic profiles, 118 podiform, 159 Magnesium, 23 plants, key, 202-3 silica pan in A2, 108 Magnet, pocket, 182-3 Pavement, 166 spodic horizon, 225 Manganese, 23, l 03-9 Peat, peaty, 87, 119-27 decomposition, amount, 125 Pollens, 55 Maori gardens, 57, 77 -o-, 168 Porosity, soil, 37, 39, 98- 100 Map, 17, 148- 50 0 horizon, 71 material, 121 - 3 pol1ens, 55 Potassium, 23, 188, 213 series, 177 Obsolete, 56, 74 Pozzolana, 109 single factor, 212 -oid, 165 soil, 119, 126-8 symbols, 143, 149 Oligotrophic, 119 turf, 115 Pre-argillised, 163 239 Pro-, 161 Sand dunes, 30, 119, 149 Soil colour, 76-82 Soil reaction, 100-3 Processes, soil, 155-6 Scintillometer, 189 Productivity, 146-7, 208-9 determination, 76 Soil register, 146 Scree, 59, 60 patterns, 78- 82 Soil rejuvenation, 53, 165-6 Profile. See So-il profile. Scrub, 47, 118, 193 Proximate parent rock, 21, 72, significance, 76-7 Soil report, 40, 148, 150 Sedentary peats, 121-4 Soil complex, 31, 141 Soil sampling, 129-31 131 Sedimentary discharge, 207 Pseudogranular, 96 Soil consistence, 25-6, 88- 92 Soil sequence, 22, 151-2 Sedimentary peats, 121-2 Soil correlation, 215-20 Soil series, 134, 138-9 Pseudomadentiform, 159 Sedimentation. 64 Pseudonut, 96 Soil creep, 59, 60 Soil set, 143 Seepage, 34, 38-9, 73 Soil density, 25, 100-1, 190-1 Soil site, 16-65 Puddling, 50 Semi-arid,. 45 Pumice, 39 Soil depth, 128-9 Soil skeleton, 55-6, 181 Senile soils, 68, 106 Soil description, 16, 221-4, 227 Soil stability, 31, 58-65 Sensitivity, 225 Soil drainage. See Drainage. Soil strength, 25, 129, 225 Sesquioxides, 22, 72 Soil erosion. See Erosion. Soil structure, 92-8 Radioactivity, 24, 188-9 Sheet erosion, 62 Soil fabric, 178, 180. casts, 51, 179 Radiocarbon dating, 53, 55 Shrubs. 193-4 Soil family, 134, 140-1 formation, 96 Rainfall, 40, 44-6 Silica, 22, 181 Soil fertility, 44, 48- 9, 130 fungi, 52 Raw humus, 115, 117 cementation, 91 transfer, 49 grade, 93 Recent soils, 127, 156, 165-6, 172 pans. 73, 108-9 Soil formation, 19, 22, 27-9 hydrology, 206 organic matter, .119 podiform soils, 159 Soil-forming factors, 17-65 microstructure, 180 phases, 138 Single slopes, 32 Soil horizons, 69- 75 plant growth, 97-8 Red-brown loams, 156, 172 Site, 16-65 boundaries, 75 Sitiform soils, 158 puddling, 50 Redox potentials, 80, 126 Category I, 158 rocks, 22 Reduction, 34, 73, 106 Skeletal soils, 158 depth, thickness, 74- 5, 128-9 seasonal dryness, 81 Regic soUs, 165-6 Skeliform soils, 158-9, 162, designations, symbols, 69-74 sitiform, 158 Regosols, 152, 156 164-5 diagnostic, 224-5 soloniform, 159 Regressive, 29, 166 phasic subdivisions, 160 organic soils, 126-7 Slick spots, 112 spadiform, 159 Relief, 28-33 Soil hydrology, 205-7 types, 93 Rendzina, 105, 155, 159 Slip erosion, 61 Soil intergrades, 157, 167-8, 173 Slope. 30-3 Soil suite, 151-4 Residual clays, 27, 162, 192 boundaries, 14, 135, 149 Soil survey, 133- 51 Residual mantle, 20 Sod, 114 horizons, 73 Soil, 13-6 Soil system, 13-4, 161 Resistant minerals, 71 zonal, 44 Soil temperature, 41-4, 147 Resistant wood, 125 composite, 168 Soil legend, 150 continuum, 13 Soil texture, 82-9 Reticulate mottles, 80, 82 Soil map, 17, 148- 50, 177 Category VII, 169 Rhizo-concretions, 106 development, 28, 151-2 hill. 141-2 Soil-mapping units, 133-4 drainage, 36, 39 Rill erosion, 61-2 Soil mixing, 156- 7, 162, 165-6 field estimation, 84-7 Rocks, 19-22, 184-5 medial, modal, 134 old, 27, 55-7 Soil moisture, 39, 44-6 nomenclature, 83- 8, 137 See also Parent rock. measurement, 190- 1 symbols, 176 Rocky, 143-4 pattern, 28 steepland, 31, 141-2 phases. 161, 167 Soil thickness, 74, 128-9 Rolling, 30-1 Soil monolith, 130, 210- 1 Soil type, 135- 8 Roots, 179- 80 undefined groupings, 143-4 Soil analyses, 130, 212--4 Soil names, 131, 134- 5, 137 land use, 151 channels. 52, 111 common, technical, 155-6, 158, mats, 119 Soil animals. 49-51, 180 pedon, 134 Soil association, 142-3 162. 172 Soil units, 133-44 penetration, 98, 108-9, 147 Soil nodules. See Nodules. Run-off, 36, 205 Soil body, 14-15, 157- 8, 165 Soil variant, 138 Soil boundaries. See Soil inter­ Soil organic matter. See Organic Solifluction, 21, 60 grades matter. Soligenous, 119, 165 Soil classification, J 33-44, 151-4, Soil pans. See Pans. Solonetzic soils. 112. 159 Salic horizon, 225 155- 74, 215-20 Soil percolation. 29. 37, 39, 129 Soloniform soils, 159 Saline soils. 35, 49, 96, 112, 200 American. 144, 224 Soil permeability, 22, 36-7 Soluble salts. 112, 2 l 4 Salinity, 112, 214 genetic, 134, 141, 155- 74 Soil phase, 138, 167, 173 Solum, 15, 19, 29, 70, 140 enleaching, 169 "natural", 215 Soil plasma, 180 Spadiform soils, 158- 9 phase, 138 "pedological", 215 Soil porosity, 37. 39, 98- 100 Spodic horizon, 225 plant indicators, 49, 201 special, 151-4 Soil processes, 155-6 Steepland soils. 31. 141- 2 Salt efflorescences, 112 units. 133-44 Soil profile, 15. 66- 9, 152 Stickiness, 25-6, 90 Salt marsh. 121 zonal arrangements, 172-4 general, medial, modal, 134 Stonelines. 21 "Salt oans". 112 Soil clays. See Clays. partial, 15 Stones, 39-40, 88. 149 Sampling, 129- 31 Soil climate, 41-6 records, 221-4, 227 Structure. See Soil Structure. _sampling, 129-31 Sub-, 163- 5. 172 240 Subalpine zone, 42, 44, 155, Value, Munsell, 76 NOTES 161-2 Vegetation, 47-9 Subantarctic zone, 44, 151-2 erosion, 59 Subargillised, 163, 165· recording, 131, 193-204 Subhydrous, 46 soil colour, 77 Subhygrous, 45 Vermiculite, 25 Subscripts, 69-74 Vesicles, 40, 99 Subtropic zone, 44, 161-2 Vivianite, 80 Subxerous, 45 Volcanic ash, 20, 185-7 Suite, 151-4 accumulation, 53 Sulphur, 23 age, 55, 186 Supra-argillised, 107 clays, 25-6 Sur- 163-5 concretions, 105 Sur~rgillised, 163 infilled tunnels, 111 Swamp, 121 radioactivity, 32 Swelling, 26 regosols, 156 Symbols, 69-74, 149, 176 Volic soils, 165

Waiotira-Wharekohe suite, 152- Taita clay loam, 27, 170-1 4 "Talasea" soils 106 Wasting regime, 156 Taupo pumice: 24, 31, 40, 173 Water, 33-4, 44-6 Taupo sandy silt, 170-1 drainage, 37-40 Taxonomic, 133, 151 erosion, 59 Te Kopuru sand, 173 hydrology, 205-7 Temperate zone, 44, 161-2 Water table. See Ground water. Temperature, 41-4, 147 Wateriogged phases, 138 Terra rossa, 27 Weathering, 24-9, 59, 156 Terraces, age, 53-4 red, 27, 55 Texture, 82-9, 169, 176 See also Argillisation. Thermal conductivity, 42 Wharekohe sandy loam, 153-4 Thornthwaite moisture regimes, Wharekohe silt loam, 173 44 Wilting point, 44-6 Tilth, 52 Wind erosion. 61, 63, 157 Timaru silt loam, 170-1 Windblown dust, sands, 53, 185 Time. See Age of soil. Tirau ash, 32 Topogenous, 119, 149 Xerous, 45 Topography, 28-40, 131, 165-6 Toposequence, 142 Torv, 114 Yellow-brown earths, northern, Trees, 193 central, etc., 155, 158-9, 172 Tropic zone, 44, 161-2 Yellow-brown loams, 156, 172 Tubular concretions, 104, 106 Yellow-brown pnrnice soils, 156, Tunnel gully erosion, 62-3 172 Tunnels. infilled, 111 Yellow-brown sands, 156, 172 Turf, 114 Yellow-grey earths, 155, 172 Tussock grasses, 194 Zinc, 23 Zonal, 172-3 Unconsolidated drift, 19-20, 185 Zones, 44, 161 Undefined soil groupings, 143-4 Zone-wide catastrophe, 163 Upland phase, 44, 161 Zoogenic moder, 115

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