Description
Book SynopsisDr. Raymond Weil, Professor, University of Maryland College Park
B.S. in Crop Science from Michigan State University, East Lansing, MI, 1970.
M.S. in Soil Science from Purdue University, West Lafayette, IN, 1973.
Ph.D. in Soil Ecology from Virginia Tech, Blacksburg, VA, 1977.
Elected Fellow in 2003 of both the Soil Science Society of America and the American Society of Agronomy.
Weil has been active in soil science research since 1972 and has made many contributions in the areas of nutrient cycling and management, environmental impact of soil management, and assessment of soil quality. His current research is focused on the assessment and improvement of soil quality and organic matter. He has conducted research in several countries outside the United States, including Ethiopia,
Table of Contents
Contents
Preface xv
1The soils around us 1
1.1 What Ecosystem Services Do Soils Perform? 2
1.2 How Do Soils Support Plant Growth? 3
1.3 How Do Soils Regulate Water Supplies? 7
1.4 How Do Soils Recycle Raw Materials? 8
1.5 How Do Soils Modify the Atmosphere? 8
1.6 What Lives in the Soil Habitat? 8
1.7 Soil as an Engineering Medium 11
1.8 The Pedosphere and the Critical Zone? 12
1.9 Soils as Natural Bodies 12
2.5 How Do Living Organisms (Including People) Affect Soil Formation? 57
2.6 How Does Topography Affect Soil Formation? 62 2.7 How Does Time Affect Soil Formation 65
2.8 Four Basic Processes of Soil Formation 67
2.9 The Soil Profile 70
2.10 Urban Soils 77
2.11 Conclusion 81
Study Questions 81
References 82
1.10 The Soil Profile and Its Layers (Horizons) 15 3
1.11 Topsoil and Subsoil 18
1.12 Soil–Interface of Air, Minerals, Water, and Life 20
1.13 What are the Mineral (Inorganic) Constituents of Soils? 20
1.14 The Nature of Soil Organic Matter 23
1.15 Soil Water–Dynamic and Complex 25
1.16 Soil Air: A Changing Mixture of Gases 26
1.17 How Do Soil Components Interact to Supply Nutrients to Plants? 26
1.18 How Do Plant Roots Obtain Nutrients? 28
1.19 Soil Health, Degradation, and Resilience 30
1.20 Conclusions 31
Study Questions 32
References 32
2 Information of soils from Parent Materials 33
2.1 Weathering of Rocks and Minerals 33
2.2 What Environmental Factors Influence Soil Formation? 41
2.3 Parent Materials 42
2.4 How Does Climate Affect Soil Formation? 55
3 Soil Classification 83
3.1 Concept of Individual Soils 83
3.2 Soil Taxonomy: A Comprehensive Classification System 85
3.3 Categories and Nomenclature of Soil Taxonomy 92
3.4 Soil Orders 94
3.5 Entisols (Recent: Little If Any Profile Development) 96
3.6 Inceptisols (Few Diagnostic Features: Inception of B Horizon) 99
3.7 Andisols (Volcanic Ash Soils) 100
3.8 Gelisols (Permafrost and Frost Churning) 102
3.9 Histosols (Organic Soils Without Permafrost) 103
3.10 Aridisols (Dry Soils) 107
3.11 Vertisols (Dark, Swelling, and Cracking Clays) 109
3.12 Mollisols (Dark, Soft Soils of Grasslands) 112
3.13 Alfisols (Argillic or Natric Horizon, Moderately Leached) 114
3.14 Ultisols (Argillic Horizon, Highly Leached) 115
3.15 Spodosols (Acid, Sandy, Forest Soils, Highly Leached) 117
3.16 Oxisols (Oxic Horizon, Highly Weathered) 118
3.17 Lower-Level Categories in Soil Taxonomy 121 3.18 Conclusion 128
Study Questions 129
References 129
4 Soil architecture and Physical Properties 130
4.1 Soil Color 130
4.2 Soil Texture (Size Distribution of Soil Particles) 134
4.3 Soil Textural Classes 139
4.4 Structure of Mineral Soils 144
4.5 Formation and Stabilization of Soil Aggregates 148
4.6 Tillage and Structural Management of Soils 156
4.7 Soil Density 161
4.8 Pore Space of Mineral Soils 171
4.9 Soil Properties Relevant to Engineering Uses 175
4.10 Conclusion 185
Study Questions 185
References 186
5 Soil Water: Characteristics and Behavior 188
5.1 Structure and Related Properties of Water 189
5.2 Capillary Fundamentals and Soil Water 191
5.3 Soil Water Energy Concepts 193
5.4 Soil Water Content and Soil Water Potential 199
5.5 The Flow of Liquid Water in Soil 207
5.6 Infiltration and Percolation 213
5.7 Water Vapor Movement in Soils 217
5.8 Qualitative Description of Soil Wetness 218
5.9 Factors Affecting Amount of Plant-Available Soil Water 222
5.10 Mechanisms by Which Plants are Supplied with Water 228
5.11 Conclusion 230
Study Questions 230
References 232
6 Soil and the hydrologic Cycle 233
6.1 The Global Hydrologic Cycle 234
6.2 Fate of Incoming Water 236
6.3 The Soil—Plant—Atmosphere Continuum (SPAC) 244
6.4 Control of ET 250
6.5 Liquid Losses of Water from the Soil 255
6.6 Percolation and Groundwater 257
6.7 Enhancing Soil Drainage 262
6.8 Septic Tank Drain Fields 269
6.9 Irrigation Principles and Practices 273
6.10 Conclusion 280
Study Questions 282
References 282
7 Soil aeration and Temperature 284
7.1 Soil Aeration–The Process 284
7.2 Means of Characterizing Soil Aeration 286
7.3 Oxidation—Reduction (Redox) Potential 288
7.4 Factors Affecting Soil Aeration and Eh 292
7.5 Ecological Effects of Soil Aeration 294
7.6 Soil Aeration in Urban Landscapes 298
7.7 Wetlands and Their Poorly Aerated Soils 301
7.8 Processes Affected by Soil Temperature 308
7.9 Absorption and Loss of Solar Energy 314
7.10 Thermal Properties of Soils 316
7.11 Soil Temperature Control 321
7.12 Conclusion 324
Study Questions 325
References 325
8 The Colloidal fraction: seat of soil Chemical and Physical activity 327
8.1 General Properties and Types of Soil Colloids 328
8.2 Fundamentals of Layer Silicate Clay Structure 332
8.3 Mineralogical Organization of Silicate Clays 334
8.4 Structural Characteristics of Nonsilicate Colloids 342
8.5 Genesis and Geographic Distribution of Soil Colloids 344
8.6 Sources of Charges on Soil Colloids 346
8.7 Adsorption of Cations and Anions 348
8.8 Cation Exchange Reactions 350
8.9 Cation Exchange Capacity (CEC) 356
8.10 Exchangeable Cations in Field Soils 362
8.11 Anion Exchange 364
8.12 Sorption of Pesticides and Groundwater Contamination 366
8.13 Binding of Biomolecules to Clay and Humus 369
9 Soil acidity 374
9.1 What Processes Cause Soil Acidification? 375
9.2 Role of Aluminum in Soil Acidity 379
9.3 Pools of Soil Acidity 380
9.4 Buffering of pH in Soils 385
9.5 How Can We Measure Soil PH? 386
9.6 Human-Influenced Soil Acidification 390
9.7 Biological Effects of Soil pH 397
9.8 Raising Soil pH by Liming 404
9.9 Alternative Ways to Ameliorate the Ill Effects of Soil Acidity 410
9.10 Lowering Soil pH 414
9.11 Conclusion 415
Study Questions 417
References 417
10 Soils of dry regions: alkalinity, salinity, and sodicity 420
10.1 Characteristics and Problems of Dry Region Soils 421
10.2 Causes of High Soil pH (Alkalinity) 429
10.3 Development of Salt-Affected Soils 431
10.4 Measuring Salinity and Sodicity 435
10.5 Classes of Salt-Affected Soils 438
10.6 Physical Degradation of Soil by Sodic Chemical Conditions 441
10.7 Biological Impacts of Salt-Affected Soils 444
10.8 Water-Quality Considerations for Irrigation 449
10.9 Reclamation of Saline Soils 452
10.10 Reclamation of Saline—Sodic and Sodic Soils 456
10.11 Management of Reclaimed Soils 461
10.12 Conclusion 461
Study Questions 462
References 463
11 Organisms and ecology of the soil 464
11.1 The Diversity of Organisms in the Soil 465
11.2 Organisms in Action 470
11.3 Abundance, Biomass, and Metabolic Activity 475
11.4 Earthworms 477
11.5 Ants and Termites 482
11.6 Soil Microanimals 486
11.7 Plant Roots 490
11.8 Soil Algae 494
11.9 Soil Fungi 494
11.10 Soil Prokaryotes: Bacteria and Archaea 502
11.11 Conditions Affecting the Growth and Activity of Soil Microorganisms 509
11.12 Beneficial Effects of Soil Organisms on Plant Communities 510
11.13 Soil Organisms and Plant Damage 512
11.14 Ecological Relationships among Soil Organisms 517
11.15 Conclusion 521
Study Questions 522
References 523
12 Soil organic Matter 526
12.1 The Global Carbon Cycle 526
12.2 Organic Decomposition in Soils 530
12.3 Factors Controlling Rates of Residue Decomposition and Mineralization 535
12.4 Genesis and Nature of Soil Organic Matter and Humus 543
12.5 Influences of Organic Matter on Plant Growth and Soil Function 550
12.6 Amounts and Quality of Organic Matter in Soils 555
12.7 Carbon Balance in the Soil—Plant—Atmosphere System 556
12.8 Environmental Factors Influencing Soil Organic Carbon Levels 560
12.9 Soil Organic Matter Management 564
12.10 Soils and Climate Change 568
12.11 Composts and Composting 575
12.12 Conclusion 579
Study Questions 580
References 581
13 Nitrogen and sulfur economy of soils 583
13.1 Influence of Nitrogen on Plant Growth and Development 584
13.2 Distribution of Nitrogen and the Nitrogen Cycle 585
13.3 Immobilization and Mineralization 587
13.4 Dissolved Organic Nitrogen 590
13.5 Ammonium Fixation by Clay Minerals 591
13.6 Ammonia Volatilization 591
13.7 Nitrification 593
13.8 Gaseous Losses by Denitrification and Anammox 596
13.9 Biological Nitrogen Fixation 601
13.10 Symbiotic Fixation with Legumes 603
13.11 Symbiotic Fixation with Nonlegumes 608
13.12 Nonsymbiotic Nitrogen Fixation 610
13.13 Nitrogen Deposition from the Atmosphere 611
13.14 The Nitrate Leaching Problem 613
13.15 Practical Management of Soil Nitrogen 617
13.16 Importance of Sulfur 625
13.17 Natural Sources of Sulfur 626
13.18 The Sulfur Cycle 631
13.19 Behavior of Sulfur Compounds in Soils 631
13.20 Sulfur Oxidation and Reduction 634
13.21 Sulfur Retention and Exchange 637
13.22 Sulfur and Soil Fertility Maintenance 638
13.23 Conclusion 639
Study Questions 639
References 640
14 Soil Phosphorus and Potassium 643
14.1 Phosphorus in Plant Nutrition and Soil Fertility 644
14.2 Effects of Phosphorus on Environmental Quality 646
14.3 The Phosphorus Cycle 652
14.4 Organic Phosphorus in Soils 657
14.5 Inorganic Phosphorus in Soils 661
14.6 Solubility of Inorganic Soil Phosphorus 664
14.7 Phosphorus-Fixation Capacity of Soils 667
14.8 Plant Strategies for Adequate Phosphorus Acquisition from Soils 672
14.9 Practical Phosphorus Management 674
14.10 Potassium: Nature and Ecological Roles 677
14.11 Potassium in Plant and Animal Nutrition 678
14.12 The Potassium Cycle 681
14.13 The Potassium Problem in Soil Fertility 683
14.14 Forms and Availability of Potassium in Soils 685
14.15 Factors Affecting Potassium Fixation in Soils 688
14.16 Practical Aspects of Potassium Management 689
14.17 Conclusion 691
Study Questions 692
References 693
15 Calcium, Magnesium, silicon, and Trace elements 696
15.1 Calcium as an Essential Nutrient 697
15.2 Magnesium as a Plant Nutrient 699
15.3 Silicon in Soil—Plant Ecology 703
15.4 Deficiency Versus Toxicity 708
15.5 Micronutrient Roles in Plants 710
15.6 Sources of Micronutrients 715
15.7 Factors Influencing the Availability of the Trace Element Cations 719
15.8 Organic Compounds as Chelates 724
15.9 Factors Influencing the Availability of the Trace Element Anions 728
15.10 Soil Management and Trace Element Needs 734
15.11 Conclusion 741
Study Questions 742
References 743
16 Practical Nutrient Management 745
16.1 Goals of Nutrient Management 745
16.2 Nutrients as Pollutants 749
16.3 Natural Ecosystem Nutrient Cycles 762
16.4 Recycling Nutrients Through Animal Manures 766
16.5 Industrial and Municipal By-Products 775
16.6 Practical Utilization of Organic Nutrient Sources 778
16.7 Inorganic Commercial Fertilizers 782
16.8 Fertilizer Application Methods 788
16.9 Timing of Fertilizer Application 792
16.10 Diagnostic Tools and Methods 793
16.11 Soil Analysis 798
16.12 Site-Index Approach to Phosphorus Management 804
16.13 Some Advances and Challenges in Fertilizer Management 807
16.14 Conclusion 812
Study Questions 814
References 815
17 Soil erosion and its Control 818
17.1 Significance of Soil Erosion and Land Degradation 819
17.2 On-Site and Off-Site impacts of Accelerated Soil Erosion 825
17.3 Mechanics of Water Erosion 828
17.4 Models to Predict the Extent of Water-Induced Erosion 831
17.5 Factors Affecting Interrill and Rill Erosion 834
17.6 Conservation Tillage 842
17.7 Vegetative Barriers 849
17.8 Control of Gully Erosion and Mass Wasting 850
17.9 Control of Accelerated Erosion on Range- and Forestland 853
17.10 Erosion and Sediment Control on Construction Sites 856
17.11 Wind Erosion: Importance and Factors Affecting It 860
17.12 Predicting and Controlling Wind Erosion 864
17.13 Tillage Erosion 867
17.14 Land Capability Classification as a Guide to Conservation 871
17.15 Progress in Soil Conservation 873
17.16 Conclusion 875
Study Questions 876
References 877
18 Soils and Chemical Pollution 879
18.1 Toxic Organic Chemicals 880
18.2 Kinds of Organic Contaminants 885
18.3 Behavior of Organic Chemicals in Soil 887
18.4 Effects of Pesticides on Soil Organisms 894
18.5 Remediation of Soils Contaminated with Organic Chemicals 896
18.6 Soil Contamination with Toxic Inorganic Substances 906
18.7 Potential Hazards of Chemicals in Sewage Sludge 912
18.8 Prevention and Remediation of Inorganic Soil Contamination 916
18.9 Landfills 919
18.10 Radionuclides in Soil 925
18.11 Radon Gas from Soils 929
18.12 Conclusion 932
Study Questions 932
References 933
19 Geographic soils information 936
19.1 Soil Spatial Variability in the Field 936
19.2 Techniques and Tools for Mapping Soils 941
19.3 Modern Technology for Soil Investigations 946
19.4 Remote Sensing in Soil Survey 951
19.5 Making a Soil Survey 959
19.6 Using Soil Surveys 962
19.7 Geographic Information Systems (GIS) 968 1
9.8 Digital Soil Maps: Properties or Polygons? 971
19.9 GIS, GPS, and Precision Agriculture 976
19.10 Conclusion 979
Study Questions 980
References 980
20 Prospects for soil health in the anthropocene 982
20.1 The Concepts of Soil Health and Soil Quality 983
20.2 Soil Resistance and Resilience 991
20.3 Soils and Global Ecosystem Services 993
20.4 Using Plants to Improve Soil Health 996
20.5 Feeding the Human Population 999
20.6 Intensified Agriculture–the Green Revolution 1000
20.7 Impacts of Vastly Increased Ratios of People to Land 1005
20.8 Sustainable Agriculture in Developed Countries 1010
20.9 Biochar: Hype or Hope for Soil Quality? 1017
20.10 Organic Farming Systems 1019
20.11 Sustainable Agriculture Systems for Resource- Poor Farmers 1026
20.12 Conclusion 1037
Study Questions 1037
References 1038
appendix a World Reference Base, Canadian, and Australian Soil Classification Systems 1041
appendix B SI Units, Conversion Factors, Periodic Table of the Elements, and Plant Names 1046
Glossary of soil science Terms 1052 index 1071
