FA 0-Unesco S oilmap of the world FAO-Unesco Soil map of the world 1: 5 000 000 Volume II North America FAO-Unesco Soil map of the world Volume I Legend Volume II North America Volume III Mexico and Central America Volume IV South America Volume V Europe Volume VI Africa Volume VII South Asia Volume VIII North and Central Asia Volume IX Southeast Asia Volume X Australasia AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS WIFOOD UNITED NATIONS EDUCATIONAL, SCIENTIFIC AND CULTURAL ORGANIZATION FAO-Unesco Soilmap of the world 1 : 5 000 000 Volume II North America Prepared by the National Cooperative Soil Survey of the United States of America, the National Soil Survey Committee of Canada, and the Food and Agriculture Organization of the United Nations Unesco-Paris 1975 The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations or theUnited Nations Educational,Scientific and Cultural Organization concerning the legal status of any country, territory, city or area or of its authori- ties,or concerning the delimitation of its frontiers or boundaries. Printed by Tipolitografia F. Failli, Rome for the Food and Agriculture Organization of the United Nations and the United Nations Educational, Scientific and Cultural Organization Published in 1975 by the United Nations Educational, Scientific and Cultural Organization Place de Fontenoy, 75700 Paris © FAO/Unesco 1975 ISBN 92 - 3 - 101126 - X Printed in Italy PREFACE The project for a joint FA0/Unesco Soil Map of the with the responsibilityof compiling the technical World was undertaken following a recommendation information, correlating the studies and coordinat- of the International Society of Soil Science.It is ing the drafting of the maps and text.FAO and the first attempt to prepare, on the basis of interna- Unesco shared the expenses involved in the realiza- tional cooperation, a soil map covering all the con- tion of the project, and Unesco undertook publica- tinents of the world in a uniform legend, thus en- tion of its results. abling the correlation of soil units and comparisons The present volume, covering the soils of North on a global scale.The project, which started in America, is the second of a set of ten which make 1961,fillsa gap inpresentknowledge ofsoil up the complete publication of the Soil Map of the potentialities throughout the world and provides a World.The first volume records introductory in- useful instrument in planning agricultural and eco- formation and presents the definitions of the elements nomic development programmes. of the legend which is used uniformly throughout the The project has been carried out under the scien- publication.Each of the nine following volumes tific authority of an international advisory panel, comprises an explanatory text and the corresponding withintheframework of FAO and Unesco pro- map sheets covering the main regions of the world. grammes.The different stages of the work included FAO and Unesco wish to express their gratitude comparative studies of soil maps, field and laboratory to the government institutions,theInternational work, and the organization of international expert Society of Soil Science, and the many individual soil meetings and study tours.The secretariat of the scientists who have contributed so much to this in- joint project, located at FAO Headquarters, was vested ternational project. CONTENTS Preface H. Phaeozems in the United States 95 I.Lithosols in Canada 96 Summaries VII I.Lithosols in the United States 97 J.Fluvisols in Canada 97 English VII J.Fluvisols in the United States 98 French IX K. Kastanozems in Canada 98 Russian XI Kastanozems in the United States 100 Spanish XIII Luvisols in Canada 101 L. Luvisols in the United States 102 Introduction 1 M. Greyzems in Canada 104 104 Acknowledgements 3 M. Greyzems in the United States O. Histosols in Canada 104 The map 4 Histosols in the United States 105 Podzols in Canada 106 4 Topographic base P. Podzols in the United States 106 4 Map units R. Regosols in Canada 107 Cartographic representation 4 Regosols in the United States 108 Sources of information 6 Solonetz in Canada 110 S.Solonetz in the United States 111 Environmental conditions 8 Andosols in Canada 111 SOIL CLIMATE 8 T.Andosols in the United States 111 Soil temperature 9 V. Vertisols in the United States 112 Soil moisture 11 W Planosols in the United States 112 Xerosols in the United States 113 VEGETATION 17 Yermosols in the United States 113 Vegetation regions 17 Solonchaks in Canada 114 PHYSIOGRAPHY AND GEOLOGY. 30 Z. Solonchaks in the United States 115 Conclusions 115 T"he soils of North America 41 Distribution of major soils 41 Appendix 1.Morphological,chemicaland physicalpropertiesof North American Description and distribution of soils, land use soils: data from selected profiles 116 and soil suitability 82 LAND USE IN NORTH AMERICA 82 Appendix 2.Table of correlated legends of DESCRIPTION, DISTRIBUTION AND SUITABILITY reference soil maps 208 OF SOILS 84 A. Acrisols in the United States 86 Figures B. Cambisols in Canada 87 B. Cambisols in the United States 88 Sources of information 6 C. Chernozems in Canada 89 Soil climate regimes 13 Chernozems in the United States 90 Potential natural vegetation regions 19 Podzoluvisols in the United States 91 Physiographic regions 33 Rendzinas in Canada 91 Surface geology 35 G. Gleysols in Canada 91 Major soil regions 43 G. Gleysols in the United States 94 Land-use regions 85 vi SUMMARY This volume describes the North American section relationships with the pattern of soils: soil of the 1: 5 000 000 Soil Map of the World. climate, The vegetation, physiography and surfacegeology. compilation of the Soil Map of North Americawas Classification of soil climate is basedon soil tem- jointly carried out in 1970-71 by the Soil Research perature and soil moisture regimes as defined in the Institute of the Canada Department of Agriculture U.S. Department of AgricultureSoil Taxonomy. and the Soil Conservation Service of the United Since the criteria used in delimiting soilclimatic States Department of Agriculture. units are those important to plant growth, thesoil climate map is complementary to the soilmap in the transfer of crop information fromone part of The maps the world to another.The main soil climatic re- gions are outlined on a small-scalemap (Figure 2). The two map sheets which make up the Soil Map Vegetation is discussed on the basis of 24 potential of North America are drawn on topographic base natural vegetation regions distinguishedon the basis maps of the 1 : 5 000 000 series of the American of the association of plant communities and their Geographical Society.The map units are associations relationships to environmental conditions.These re- of soil units divided into texture and slope classes. gions are outlined on a small-scalemap (Figure 3). They are marked on the maps by symbols.The The text gives some brief notes on each region. dominant soils are shown by colours and phases The discussion of physiographic regions includes are shown by overprints. brief statements on the geology and geomorphology A small inset map shows the reliability of soil of broad areas of the subcontinent.Twelve regions information from which the map was compiled. are delineated on a small-scale map (Figure 4). Detaileddefinitions of thesoil units and full Surface geology is shown only by a map (Figure 5); descriptions of all the terms used may be found in there is no explanatory text.Fourteen map units Volume I. show dominant rock types grouped according to geologic era. The text SOILS AND LAND USE The first chapter describes the development of the Chapters 5 and 6, describing the soils of the con- project in North America and gives some possible tinent, contain an extensive table of soil associations, uses of the map. The second acknowledges the co- an account of the distribution of the main soils, and operation of participating agencies and the large a discussion of land use and soil suitabilities for number of people who contributed to the maps and agriculture. text, and the third gives a brief explanation of the The table of soil associations lists all the map units soil legend, which is described in detail in Volume I, in alphabetical order of symbols.Other columns and the principal sources of information utilized in show: the compilation of the map. The main chapters of this volume deal with en- Associated soils vironmental conditions, soil distribution, land use Inclusions and suitability. Phases Areas of units in1 000 hectares ENVIRONMENTAL CONDITIONS Climate Regions of occurrence Chapter 4 contains brief accounts, with maps, of Vegetation the four factors of the environment that have close Lithology or parent materials vii The distribution of major soils is discussed on the continent are in an environment generally better basis of 18 major soil regions which are outlined on suited for farming, although in the southwestern a small-scale map (Figure 6).The main soils of part they are subject to limitations imposed by a each region are discussed in relation to factors of deficiency of moisture and in the western and east- the environment, and a brief account of their extent ern parts by steep slopes of mountains and highlands. and location is given. In only 5 percent of Canada are the soils used for Description and distribution of soils, land use and farm enterprises. An additional 2 percent of the soil suitability are discussedin Chapter6.In a land area of the country has potential for develop- short introductory note to the chapter, distribution ment, although some of it has limitations imposed of the principal kinds of land use in North America by climate and physical features.In the United is outlined and is further illustrated in Figure 7.