FUNDAMENTALS OF SOIL SCIENCE FUNDAMENTALS OF SOIL SCIENCE EIGHTH EDITION HENRY D FOTH Michigan State University JOHN WILEY & SONS New York • Chichester • Brisbane • Toronto • Singapore Cover Photo Soil profile developed from glacio-fluvial sand in a balsam fir-black spruce forest in the Laurentian Highlands of Quebec, Canada The soil is classified as a Spodosol (Orthod) in the United States and as a Humo-Ferric Podzol in Canada Copyright © 1943, 1951 by Charles Ernest Millar and Lloyd M Turk Copyright © 1958, 1965, 1972, 1978, 1984, 1990, by John Wiley & Sons, Inc All rights reserved Published simultaneously in Canada Reproduction or translation of any part of this work beyond that permitted by Sections 107 and 108 of the 1976 United States Copyright Act without the permission of the copyright owner is unlawful Requests for permission or further information should be addressed to the Permissions Department, John Wiley & Sons Library of Congress Cataloging In Publication Data: Foth, H D Fundamentals of soil science / Henry D Foth.-8th ed p cm I ncludes bibliographical references ISBN 0-471-52279-1 Soil science I Title S591.F68 1990 631.4-dc20 90-33890 CIP Printed in the United States of America 1098765432 Printed and bound by the Arcata Graphics Company PREFACE The eighth edition is a major revision in which there has been careful revision of the topics covered as well as changes in the depth of coverage Many new figures and tables are included Summary statements are given at the ends of the more difficult sections within chapters, and a summary appears at the end of each chapter Many nonagricultural examples are included to emphasize the importance of soil properties when soils are used in engineering and urban settings The topics relating to environmental quality are found throughout the book to add interest to many chapters Several examples of computer application are included The original Chapter 1, "Concepts of Soil," was split into two chapters Each chapter emphasizes an important concept of soil-soil as a medium for plant growth and soil as a natural body Topics covered in Chapter include the factors affecting plant growth, root growth and distribution, nutrient availability (including the roles of root interception, mass flow and diffusion), and soil fertili ty and productivity The importance of soils as a source of nutrients and water is stressed in Chapter and elsewhere throughout the book Chapter covers the basic soil formation processes of humification of organic matter, mineral weatheri ng, leaching, and translocation of colloids The i mportant theme is soil as a three-dimensional body that is dynamic and ever-changing The concepts developed in the first two chapters are used repeatedly throughout the book The next five chapters relate to soil physical properties and water The material on tillage and traffic was expanded to reflect the increasing effect of tillage and traffic on soils and plant growth and is considered in Chapter The nature of soil water is presented as a continuum of soil water potentials in Chapter Darcy's law is developed and water flow is discussed as a function of the hydraulic gradient and conductivity Darcy's Law is used in Chapter 6, "Soil Water Management," i n regard to water movement in infiltration, drainage, and irrigation Chapter also covers disposal of sewage effluent in soils and prescription athletic turf (PAT) as an example of precision control of the water, air, and salt relationships in soils used for plant growth "Soil Erosion," Chapter 7, has been slightly reorganized with greater emphasis on water and wind erosion processes Chapters and 9, "Soil Ecology" and "Soil Organic Matter," are complimentary chapters relati ng to the biological aspects of soils The kinds and nature of soil organisms and nutrient cycling remain as the central themes of Chapter An expanded section on the rhizosphere has been i ncluded The distinctions between labile and stable organic matter and the interaction of organic matter with the minerals (especially clays) are central themes of Chapter Also, the concept of cation exchange capacity is minimally developed i n the coverage of the nature of soil organic matter i n Chapter Chapter 10, "Soil Mineralogy," and Chapter 11, "Soil Chemistry", are complimentary chapters rel ating to the mineralogical and chemical properties of soils The evolution theme included in Chapter is used to develop the concept of changing mineralogical and chemical properties with time Soils are characterized as being minimally, moderately, and intensively weathered, and these distinctions are used in discussions of soil pH, liming, soil fertility and fertilizer use, soil genesis, and land use Chapters 12 through 15 are concerned with the general area of soil fertility and fertilizer use Chapters 12 and 13 cover the macronutrients and micronutrients plus toxic elements, respectively V vi PREFACE Chapters 14 and 15 cover the nature of fertilizers and the evaluation of soil fertility and the use of fertilizers, respectively Greater stress has been placed on mass flow and diffusion in regard to nutrient uptake The interaction of water and soil fertility is developed, and there is expanded coverage of soil fertility evaluation and the methods used to formulate fertilizer recommendations Recognition is made of the increasing frequency of high soil test results and the implications for fertilizer use and environmental quality Greater coverage is given to animal manure as both a source of nutrients and a source of energy Information on land application of sewage sludge and on sustainable agriculture has been added Throughout these four chapters there is a greater emphasis on the importance of soil fertility and fertilizers and on the environmental aspects of growing crops The next four chapters (Chapters 16, 17, 18, and 19) relate to the areas of soil genesis, soil taxonomy, soil geography and land use, and soil survey and land use interpretations In this edition, the subjects of soil taxonomy (classification) and of soil survey and land use interpretations have received increased coverage in two small chapters The emphasis in the soil geography and land use chapter is at the suborder level References to l ower categories are few Color photographs of soil profiles are shown in Color Plates and No reference to Soil Taxonomy (USDA) is made until taxonomy is covered in Chapter 17 This allows a consideration of soil classification after soil properties have been covered This arrangement also makes the book more desirable for use in two-year agricultural technology programs and overseas, in countries where Soil Taxonomy is not used The final chapter, "Land and the World Food Supply," includes a section on the world grain trade and examines the importance of nonagronomic factors in the food-population problem Both English and metric units are used in the measurement of crop yields, and for some other parameters Using both kinds of units should satisfy both United States and foreign readers Special thanks to Mary Foth for the artwork and to my late son-in-law, Nate Rufe, for photographic contributions Over the years, many colleagues have responded to my queries to expand my knowledge and understanding Others have provided photographs The reviewers also have provided an invaluable service To these persons, I am grateful Finally, this book is a STORY about soil The story reflects my love of the soil and my devotion to promoting the learning and understanding of soils for more than 40 years I hope that all who read this book will find it interesting as well as i nformative Henry D Foth East Lansing, Michigan BRIEF CONTENTS VII DETAILED CONTENTS CHAPTER SOIL PHYSICAL PROPERTIES 22 CHAPTER SOIL AS A MEDIUM FOR PLANT GROWTH FACTORS OF PLANT GROWTH Support for Plants Essential Nutrient Elements Water Requirement of Plants Oxygen Requirement of Plants Freedom from Inhibitory Factors PLANT ROOTS AND SOIL RELATIONS Development of Roots in Soils Extensiveness of Roots in Soils Extent of Root and Soil Contact Roles of Root Interception, Mass Flow, and Diffusion SOIL TEXTURE 22 The Soil Separates 22 Particle Size Analysis 24 Soil Textural Classes 25 Determining Texture by the Field Method Influence of Coarse Fregments on Class Names 26 Texture and the Use of Soils 26 SOIL FERTILITY AND SOIL PRODUCTIVITY SOIL STRUCTURE 27 I mportance of Structure 28 Genesis and Types of Structure Grade and Class 29 Managing Soil Structure 29 DENSITY AND WEIGHT RELATIONSHIPS Particle Density and Bulk Density 32 Weight of a Furrow-Slice of Soil 33 Soil Weight on a Hectare Basis 34 CHAPTER SOIL AS A NATURAL BODY 11 SOIL PORE SPACE AND POROSITY 34 Determination of Porosity 34 Effects of Texture and Structure on Porosity Porosity and Soil Aeration 35 THE PARENT MATERIAL OF SOIL 12 Bedrock Weathering and Formation of 12 Parent Material 13 Sediment Parent Materials SOIL FORMATION 13 Soil-Forming Processes 14 ri Formation of A and C Ho zons Formation of B Horizons 14 The Bt Horizon 15 The Bhs Horizon 17 Formation of E Horizons Formation of Horizons 28 SOIL CONSISTENCE 31 Soil Consistence Terms 31 SOIL COLOR 36 Determination of Soil Color 37 Factors Affecting Soil Color 37 Significance of Soil Color 37 SOIL TEMPERATURE 38 Heat Balance of Soils 38 Location and Temperature Control of Soil Temperature Permafrost 40 14 17 18 SOILS AS NATURAL BODIES 18 The Soil-Forming Factors 18 Soil Bodies as Parts of Landscapes 19 How Scientists Study Soils as Natural Bodies 19 20 I mportance of Concept of Soil as Natural Body ix 25 39 39 CHAPTER TILLAGE AND TRAFFIC 42 EFFECTS OF TILLAGE ON SOILS AND PLANT GROWTH 42 42 Management of Crop Residues 32 35 I NDEX 355 356 I NDEX I NDEX 357 358 I NDEX I NDEX 359 360 I NDEX COLOR PLAT[; Left is nitrogen-deficient section of corn leaf and cut open section of stem that remains uncolored when treated with diaphenylamine, indicating low nitrate level in plant sap On right the leaf is dark green and diaphenylamine produces a dark blue color indicative of high nitrate level in plant sap Nitrogen deficiency on corn Lower leaves turn yellow along midrib, starting at the leaf tip Potassium deficiency on corn Lower leaves have yellow margins Potassium deficiency on alfalfa (and clovers) shows as a series of white dots near leaf margins ; in advanced stages entire leaf margin turns white (Courtesy American Potash Institute ) COLOR PLATE Phosphorus deficiency on corn is indicated by purplish discoloration Iron deficiency on pin oak The leaf veins remain green as the intervein areas lose their green color Iron deficiency on roses Green veins with yellow intervein areas, showing most on newest leaves C^ COLOR PLATE Manganese deficiency on kidney beans Leaf veins remain green as the intervein areas lose their green color and turn yellow Zinc deficiency of navy beans grown on calcareous soil The small unfertilized zinc-deficient plants stand in marked contrast to the taller plants that were fertilized with zinc A case where zinc fertilization is necessary to produce a crop Boron deficiency on sugar beets causes heart rot Most advanced symptom is on left COLOR PLATE Magnesium deficiency on coffee Veins remain green and intervein areas turn yellow Manganese-treated plants in rear showing no deficiency Plants in foreground are unfertilized and difference in degree of manganese deficiency symptoms is indicative of varietal response to limited soil manganese Excess soluble salt symptoms on geranium The leaf margins turn yellow and become necrotic to w f- J CL I J [...]... horizon Such soils are AC soils; the evolution of an AC soil is illustrated in Figure 2.4 Formation of B Horizons The subsoil in an AC soil consists of the C horizon and, perhaps, the upper part of the parent material Under favorable conditions, this subsoil layer 2.4 Sequential evolution of some soil horizons in a sediment parent material FIGURE SOIL FORMATION FIGURE 2.5 A soil scientist observing soil properties... Nature of Cation Exchange 165 Cation Exchange Capacity of Soils 166 Cation Exchange Capacity Versus Soil pH 167 Kinds and Amounts of Exchangeable Cations 168 Exchangeable Cations as a Source of Plant Nutrients 169 Anion Exchange 169 SOIL pH 170 Determination of Soil pH 170 Sources of Alkalinity 170 Carbonate Hydrolysis 170 Mineral Weathering 171 Sources of Acidity 171 Development and Properties of Acid Soils... CHEMISTRY 164 CHEMICAL COMPOSITION OF SOILS MANAGEMENT OF SOIL pH 178 Lime Requirement 179 Lime Requirement of Intensively Weathered Soils 180 Lime Requirement of Minimally and Moderately Weathered Soils 180 181 The Liming Equation and Soil Buffering 182 Some Considerations in Lime Use Management of Calcareous Soils 182 Soil Acidulation 183 171 186 NITROGEN 186 The Soil Nitrogen Cycle 187 Dinitrogen... with the evolution of soil layers This is shown in Figure 2.2, where a single soil horizon, the topsoil layer, overlies the R layer, or bedrock The topsoil layer i s about 12 inches (30 cm) thick and has evolved slowly at a rate controlled by the rate of rock weathering The formation of a centimeter of soil i n hundreds of years is accurate for this example of soil formation Rates of parent material... Disposal of Septic Tank Effluent 94 Land Disposal of Municipal Wastewater PLANT AND SOIL WATER RELATIONS 66 Available Water-Supplying Power of Soils 66 Water Uptake from Soils by Roots 67 Diurnal Pattern of Water Uptake 68 Pattern of Water Removal from Soil 69 Soil Water Potential Versus Plant Growth 69 Role of Water Uptake for Nutrient Uptake 71 CHAPTER 7 SOIL EROSION 100 71 82 Rate and Timing of Irrigation... arrangement of soil particles, and an intermediate content of organic matter A soil with A, B, and C horizons is shown in Figure 2.5 During the early phases of soil evolution, the soil formation processes progressively transform parent material into soil, and the soil increases in thickness The evolution of a thin AC soil into a thick ABwC soil is illustrated in Figure 2.4 15 The Bt Horizon Soil parent... concept of soil as a medium for plant growth i s an ancient concept and dates back to at least the beginning of agriculture The concept emphasizes the soil' s role in the growth of plants Important aspects of the soil as a medium for plant growth are: (1) the role of the soil in supplying plants with growth factors, (2) the development and distribution of roots in soils, and (3) the movement of nutrients,... Role of Aluminum 172 Moderately Versus Intensively Weathered Soils 173 174 Role of Strong Acids Acid Rain Effects 174 Soil Buffer Capacity Summary Statement 174 176 SIGNIFICANCE OF SOIL pH 176 Nutrient Availability and pH 177 178 Effect of pH on Soil Organisms Toxicities in Acid Soils 178 pH Preferences of Plants 178 CHAPTER 12 PLANT -SOIL MACRONUTRIENT RELATIONS 186 DEFICIENCY SYMPTOMS CHAPTER 11 SOIL. .. Effects of Tillage on Structure and Porosity Surface Soil Crusts 44 Minimum and Zero Tillage Concepts 44 Tilth and Tillage 45 TRAFFIC AND SOIL COMPACTION 46 Compaction Layers 46 Effects of Wheel Traffic on Soils and Crops Effects of Recreational Traffic 47 Effects of Logging Traffic on Soils and Tree Growth 48 Controlled Traffic 49 43 47 FLOODING AND PUDDLING OF SOIL 50 Effects of Flooding 50 Effects of. .. RADIOACTIVE ELEMENTS 247 CHAPTER 16 SOIL GENESIS 250 218 ROLE OF TIME IN SOIL GENESIS 250 Case Study of Soil Genesis 250 Time and Soil Development Sequences 221 FERTILIZER TERMINOLOGY 221 Grade and Ratio 221 General Nature of Fertilizer Laws 222 Types of Fertilizers 222 252 ROLE OF PARENT MATERIAL IN SOIL GENESIS 253 Consolidated Rock as a Source of Parent Material 253 Soil Formation from Limestone Weathering