Pedology Titles of related interest (in sequence of publication) Physical processes of sedimentation Geomorphology and engineering J. R. L. Allen D. R. Coates (ed.) The formation of soil material Geomorphology in arid regions T. R. Paton D. O. Doehring (ed.) Petrology of the sedimentary rocks Geomorphological techniques J. T. Greensmith A. S. Goudie (ed.) Geology for civil engineers Terrain analysi.; and remote sensing A. C. McLean & c. D. Gribble J. R. G. Townshend (ed.) A dynamic stratigraphy of the British British rivers Isles J. Lewin (ed.) R. Anderton, P. H. Bridges, M. R. Soils and landforms Leeder & B. W. Sellwood A. J. Gerrard Thresholds in geomorphology Soil survey and land evaluation D. R. Coates & J. D. Vitek (eds) D. Dent & A. Young Water planning in Britain Environmental archaeology D. J. Parker & E. C. Penning­ M. L. Shackley Rowsell Adjustments of the fluvial system Coastal geomorphology D. D. Rhodes & G. P. Williams D. R. Coates (ed.) (eds) Fluvial geomorphology Applied geomorphology M. Morisawa (ed.) R. G. Craig & J. L. Craft (eds) Glacial geomorphology Space and time in geomorphology D. R. Coates (ed.) C. E. Thorn (ed.) Theories of landform development Sedimentology: process and product W. N. Melhorn & R. C. Flemal M. R. Leeder (eds) Sedimentary structures J. D. Collinson & D. B. Thompson Pedogenesis and classifica tion P. Duchaufour Translated by TR. Paton ASSOCIATE PROFESSOR OF EARTH SCIENCES, MACQUARIE UNIVERSITY, SYDNEY, AUSTRALIA London GEORGE ALLEN & UNWIN Boston Sydney © Masson, Paris, 1977 English edition © George Allen & Unwin, 1982 Softcover reprint of the hardcover I st edition 1982 Pedology under the direction of Philippe Duchaufour Honorary Director of the CNRS Pedology Centre and Bernard Souchier Director of the CNRS Pedology Centre This book is the English translation of Pedogenese et classification, the first volume of Pedologie, published by Masson in 1977. The English translation of the second volume, subtitled Constituants et proprietes, is published by Academic Press. This book is copyright under the Berne Convention. No reproduction without permission. All rights reserved. George Allen & Unwin (Publishers) Ltd, 40 Museum Street, London WCIA lLU, UK George Allen & Unwin (Publishers) Ltd, Park Lane, Hemel Hempstead, Herts HP2 4TE, UK Allen & Unwin Inc., 9 Winchester Terrace, Winchester, Mass 01890, USA George Allen & Unwin Australia Pty Ltd, 8 Napier Street, North Sydney, NSW 2060, Australia First published by George Allen & Unwin in 1982 British Library Cataloguing in Publication Data Duchaufour, Philippe Pedology: pedogenesis and classification 1. Soil science I. Title II. Pedologie. Pedogenese et classification. English 631.4 S593 ISBN-13 978-94-011-6005-6 e-ISBN-13: 978-94-011-6003-2 DOl: 10.1007/978-94-011-6003-2 Library of Congress Cataloging in Publication Data Duchaufour, Philippe, 1912- Pedology: pedogenesis and classification. Translation of: Pedogenese et classification, the first volume of Pedologie, published by Masson in 1977. Includes bibliographical references and index. 1. Soil science. 2. Soil formation. 3. Soils­ Classification. I. Title. S591.D7913 1982 631.4 82-11517 Set in 10 on 12 point Times by Preface Ltd, Salisbury, Wilts. by Butler & Tanner Ltd, Frome and London Preface This book is the first of two volumes intended to replace the old and now out of print Precis de pedologie, the previous three editions of which were pro­ duced by the same publisher in 1960, 1965 and 1970. It was apparent that the term 'precis', which means that the text was neces­ sarily condensed and summarised, no longer corresponded with the present day situation, for pedology has developed considerably in the past 10 years and it now makes use of the most modern and varied research techniques. It has become an entirely separate discipline and has assumed, at least in certain countries, considerable importance. In addition, different schools of thought have developed and their sometimes contradictory viewpoints are presented at many international conferences, which, if valid conclusions are to be reached from them, required considerable space for discussion. Thus, even by being very concise it was no longer possible to deal with the whole of soil science within the space of one volume, so that a two volume format became a necessity. As soil science is known to have two fundamentally distinct aspects, it has been easy to determine the contents of each volume and also to give each an identity and unity, as well as enabling a different kind of presentation to be made in each case. The purely pedological aspect of soil science, that is to say the one that deals with soil dynamics as a function of the environment, cannot be divided, for it involves an environmental synthesis which of necessity must be the work of a single author who is capable of presenting a general environmental classification of soils, otherwise the necessary unity would be lacking. This volume attempts to do precisely this: the study of pedogenesis and soil classification. The other aspect concerns all of the physical, chemical and biological prop­ erties of soil, which makes it more analytical, less theoretical and more applied, so that its importance to foresters and agronomists is readily appar­ ent. Thus, the second volume deals with Constituents and properties ofsoils, in which, even though reference is made to the connections which exist between each chapter, overall synthesis is more limited than in Volume 1. Of necessity, as only experts in particular fields can write about them in a clear and com­ petent manner, several authors have contributed one or more chapters covering their particular specialist areas. Thus the two volumes of this pedological series are part of a whole, but at the same time each of them is complete in itself and thus independent of the other. In the English edition, the French text has been brought up to date and vi PREFACE the bibliography completed. For his translation Professor Paton is to be par­ ticularly thanked. It must be particularly mentioned that the completion of this first volume has been possible only by the help of research groups in the Biological Centre of Pedology at Nancy. For the preparation of the manuscript and illustrations Miss E. Jeanroy and M. P. Sueur, whose support has never faltered, are to be greatly thanked. Ph. Duchaufour General key slightly decomposed organic accumulation of dehydrated ~. layer [ill] ferric iron (red) slightly active humic horizon localised precipitation of ferric iron active humic horizon with iron- manganese concretions - crumb structure ~ calcium carbonate gley : ferrous iron dominant -~ (greenish grey) 2 : 1 clays (illite, vermiculite, g montmorillonrte - with absorbed free alumina iron oxides) E3 1 : 1 clays (kaolinite) weathering parent rock ~ ashy or bleached horizon unweathered siliceous parent rock ~ accumulation of ferric hydrate unweathered calcareous parent rock [IJIIJJ (bright ochreous or rusty) Note: the abundance of these different materials is indicated by the spacing of the lines or the density of the symbols utilised Contents Preface page v General key to symbols VII List of tables Xlll List of plates xiv Part I THE PHYSICOCHEMICAL PROCESSES OF PEDOGENESIS Introduction and definitions 3 1 Weathering and clay formation 5 I General introduction 5 II Geochemical weathering: total hydrolysis and neoformation cl~ 9 III Biochemical weathering: dominated by gradual hydrolysis and transformations 12 IV Influence of environmental factors on weathering 17 V Conclusion 22 References 26 2 The dynamics of organic matter 28 I Introduction 28 II Biological humification: biochemical processes 32 III The effect of environmental factors on biological humification 37 IV The slow development of humic materials; maturation 49 V Classification of humus 53 VI Conclusion 63 References 64 3 The movement of material within soils 67 I Introduction and definitions 67 II Mechanisms of migration: eluviation and illuviation 71 III Biogeochemical cycles and biological processes of upward movement 86 IV Influence of environmental factors on the transport of material within soils 96 V Conclusion 104 References 104 x CONTENTS 4 General principles of the origin and develop- ment of soils page 108 I Soil development cycles: definitions 108 II The time factor: determination of soil age 112 III Effect of environmental factors on development cycles 119 IV Study of long cycles 141 V Conclusion 152 References 153 Part II PEDOGENESIS: THE BASIS OF SOIL CLASSIFICATION 5 Soil classification 159 I General introduction 159 II Criteria used in modem classifications 161 III Definition and hierarchical position of taxonomic units: horizons 165 IV The American classification (soil taxonomy) 168 V F AO classification 173 VI The proposed environmental classification 175 References 180 6 Immature soils and soils with little profile differen- tiation 182 A Immature soils 182 I General characters and classification 182 II Immature climatic soils 183 III Immature erosional soils 185 IV Immature depositional soils 185 B Unsaturated humic soils 189 I Introduction 189 II Rankers 191 III Andosols 196 References 209 7 Caicimagnesian soils 211 I Introduction: general characters 211 II Environment, morphology and biochemistry of the basic types 212 III Formation of humus-carbonate complexes: biochemical and geochemical processes 217 IV Development of ca1cimagnesian soils in temperate plain lands 220 V Development of ca1cimagnesian soils at high altitude 225 VI Classification of ca1cimagnesian