| Preface | p. xv |
| The Soils Around Us | p. 1 |
| Functions of Soils in Our Ecosystem | p. 2 |
| Medium for Plant Growth | p. 3 |
| Regulator of Water Supplies | p. 6 |
| Recycler of Raw Materials | p. 7 |
| Habitat for Soil Organisms | p. 7 |
| Engineering Medium | p. 8 |
| Soil as Environmental Interface | p. 9 |
| Soil as a Natural Body | p. 10 |
| The Soil Profile and Its Layers (Horizons) | p. 11 |
| Topsoil and Subsoil | p. 15 |
| Soil: The Interface of Air, Minerals, Water, and Life | p. 17 |
| Mineral (Inorganic) Constituents of Soils | p. 18 |
| Soil Organic Matter | p. 20 |
| Soil Water: A Dynamic Solution | p. 21 |
| Soil Air: A Changing Mixture of Gases | p. 23 |
| Interaction of Four Components to Supply Plant Nutrients | p. 24 |
| Nutrient Uptake by Plant Roots | p. 26 |
| Soil Quality, Degradation, and Resilience | p. 27 |
| Conclusion | p. 29 |
| Study Questions | p. 29 |
| References | p. 30 |
| Formation of Soils from Parent Materials | p. 31 |
| Weathering of Rocks and Minerals | p. 31 |
| Physical Weathering (Disintegration) | p. 36 |
| Biogeochemical Weathering | p. 36 |
| Factors Influencing Soil Formation | p. 39 |
| Parent Materials | p. 40 |
| Residual Parent Material | p. 42 |
| Colluvial Debris | p. 42 |
| Alluvial Stream Deposits | p. 42 |
| Marine Sediments | p. 45 |
| Parent Materials Transported by Glacial Ice and Meltwaters | p. 46 |
| Parent Materials Transported by Wind | p. 49 |
| Organic Deposits | p. 52 |
| Climate | p. 54 |
| Biota: Living Organisms | p. 54 |
| Topography | p. 61 |
| Time | p. 62 |
| Four Basic Processes of Soil Formation | p. 64 |
| The Soil Profile | p. 69 |
| Conclusion | p. 73 |
| Study Questions | p. 73 |
| References | p. 74 |
| Soil Classification | p. 75 |
| Concept of Individual Soils | p. 76 |
| Comprehensive Classification System: Soil Taxonomy | p. 79 |
| Categories and Nomenclature of Soil Taxonomy | p. 84 |
| Soil Orders | p. 86 |
| Entisols (Recent: Little If Any Profile Development) | p. 88 |
| Inceptisols (Few Diagnostic Features: Inception of B Horizon) | p. 92 |
| Andisols (Volcanic Ash Soils) | p. 93 |
| Gelisols (Permafrost and Frost Churning) | p. 94 |
| Histisols (Organic Soils without Permafrost) | p. 96 |
| Aridisols (Dry Soils) | p. 98 |
| Vertisols (Dark, Swelling and Cracking Clays) | p. 100 |
| Mollisols (Dark, Soft Soils of Grasslands) | p. 103 |
| Alfisols (Argillic or Natric Horizon, Medium to High Bases) | p. 105 |
| Ultisols (Argillic Horizon, Low Bases) | p. 107 |
| Spodosols (Acid, Sandy, Forest Soils, Low Bases) | p. 109 |
| Oxisols (Oxic Horizon, Highly Weathered) | p. 110 |
| Lower-Level Categories in Soil Taxonomy | p. 111 |
| Conclusion | p. 118 |
| Study Questions | p. 119 |
| References | p. 119 |
| Soil Architecture and Physical Properties | p. 121 |
| Soil Color | p. 122 |
| Soil Texture (Size Distribution of Soil Particles) | p. 123 |
| Soil Textural Classes | p. 127 |
| Structure of Mineral Soils | p. 133 |
| Soil Density | p. 136 |
| Pore Space of Mineral Soils | p. 147 |
| Formation and Stabilization of Soil Aggregates | p. 152 |
| Tillage and Structural Management of Soils | p. 160 |
| Soil Properties Relevant to Engineering Uses | p. 165 |
| Conclusion | p. 172 |
| Study Questions | p. 173 |
| References | p. 174 |
| Soil Water: Characteristics and Behavior | p. 176 |
| Structure and Related Properties of Water | p. 177 |
| Capillary Fundamentals and Soil Water | p. 180 |
| Soil Water Energy Concepts | p. 183 |
| Soil Water Content and Soil Water Potential | p. 187 |
| The Flow of Liquid Water in Soil | p. 195 |
| Infiltration and Percolation | p. 200 |
| Water Vapor Movement in Soils | p. 204 |
| Qualitative Description of Soil Wetness | p. 205 |
| Factors Affecting Amount of Plant-Available Soil Water | p. 210 |
| Mechanisms by Which Plants Are Supplied with Water | p. 213 |
| Conclusion | p. 215 |
| Study Questions | p. 216 |
| References | p. 217 |
| Soil and the Hydrologic Cycle | p. 219 |
| The Global Hydrologic Cycle | p. 220 |
| Fate of Precipitation and Irrigation Water | p. 222 |
| The Soil-Plant-Atmosphere Continuum | p. 228 |
| Efficiency of Water Use | p. 233 |
| Control of Evapotranspiration (ET) | p. 235 |
| Control of Surface Evaporation (E) | p. 236 |
| Liquid Losses of Water from the Soil | p. 240 |
| Percolation and Groundwaters | p. 243 |
| Enhancing Soil Drainage | p. 247 |
| Septic Tank Drain Fields | p. 258 |
| Irrigation Principles and Practices | p. 261 |
| Conclusion | p. 269 |
| Study Questions | p. 270 |
| References | p. 271 |
| Soil Aeration and Temperature | p. 272 |
| Soil Aeration--The Process | p. 273 |
| Means of Characterizing Soil Aeration | p. 274 |
| Oxidation-Reduction (Redox) Potential | p. 277 |
| Factors Affecting Soil Aeration | p. 280 |
| Ecological Effects of Soil Aeration | p. 283 |
| Aeration in Relation to Soil and Plant Management | p. 286 |
| Wetlands and Their Poorly Aerated Soils | p. 287 |
| Processes Affected by Soil Temperature | p. 294 |
| Absorption and Loss of Solar Energy | p. 301 |
| Thermal Properties of Soils | p. 305 |
| Soil Temperature Control | p. 309 |
| Conclusion | p. 313 |
| Study Questions | p. 313 |
| References | p. 314 |
| Soil Colloids: Seat of Soil Chemical and Physical Activity | p. 316 |
| General Properties and Types of Soil Colloids | p. 317 |
| Fundamentals of Layer Silicate Clay Structure | p. 321 |
| Mineralogical Organization of Silicate Clays | p. 324 |
| Structural Characteristics of Nonsilicate Colloids | p. 329 |
| Genesis and Geographic Distribution of Soil Colloids | p. 333 |
| Sources of Charges on Soil Colloids | p. 336 |
| Adsorption of Cations and Anions | p. 339 |
| Cation Exchange Reactions | p. 341 |
| Cation Exchange Capacity | p. 345 |
| Exchangeable Cations in Field Soil | p. 349 |
| Anion Exchange | p. 352 |
| Sorption of Pesticides and Groundwater Contamination | p. 354 |
| Binding of Biomolecules to Clay and Humus | p. 355 |
| Physical Implications of Swelling-Type Clays | p. 357 |
| Environmental Uses of Swelling-Type Clays | p. 358 |
| Conclusion | p. 359 |
| Study Questions | p. 360 |
| References | p. 361 |
| Soil Acidity | p. 363 |
| The Process of Soil Acidification | p. 364 |
| Role of Aluminum in Soil Acidity | p. 369 |
| Pools of Soil Acidity | p. 369 |
| Buffering of pH in Soils | p. 374 |
| Determination of Soil pH | p. 377 |
| Human-Influenced Soil Acidification | p. 380 |
| Biological Effects of Soil pH | p. 387 |
| Raising Soil pH by Liming | p. 394 |
| Alternative Ways to Ameliorate the III Effects of Soil Acidity | p. 400 |
| Lowering Soil pH | p. 403 |
| Calcium and Magnesium as Plant Nutrients | p. 404 |
| Conclusion | p. 408 |
| Study Questions | p. 409 |
| References | p. 410 |
| Soils of Dry Regions: Alkalinity, Salinity, and Sodicity | p. 412 |
| Causes of Alkalinity: High Soil pH | p. 413 |
| Characteristics and Problems of Alkaline Soils | p. 415 |
| Development of Salt-Affected Soils | p. 419 |
| Measuring Salinity and Sodicity | p. 422 |
| Classes of Salt-Affected Soils | p. 426 |
| Growth of Plants on Salt-Affected Soils | p. 430 |
| Water-Quality Considerations for Irrigation | p. 434 |
| Reclamation of Saline Soils | p. 436 |
| Reclamation of Saline-Sodic and Sodic Soils | p. 441 |
| Management of Reclaimed Soils | p. 445 |
| Conclusion | p. 445 |
| Study Questions | p. 446 |
| References | p. 447 |
| Organisms and Ecology of the Soil | p. 449 |
| The Diversity of Organisms in the Soil | p. 450 |
| Organisms in Action | p. 452 |
| Organism Abundance, Biomass, and Metabolic Activity | p. 457 |
| Earthworms | p. 459 |
| Ants and Termites | p. 463 |
| Soil Microanimals | p. 466 |
| Roots of Higher Plants | p. 470 |
| Soil Algae | p. 473 |
| Soil Fungi | p. 473 |
| Soil Bacteria | p. 481 |
| Soil Actinomycetes | p. 482 |
| Conditions Affecting the Growth of Soil Microorganisms | p. 483 |
| Beneficial Effects of Soil Organisms | p. 484 |
| Soil Organisms and Damage to Higher Plants | p. 487 |
| Ecological Relationships Among Soil Organisms | p. 490 |
| Genetically Engineered Microorganisms | p. 493 |
| Conclusion | p. 495 |
| Study Questions | p. 495 |
| References | p. 495 |
| Soil Organic Matter | p. 498 |
| The Global Carbon Cycle | p. 498 |
| The Process of Decomposition in Soils | p. 501 |
| Factors Controlling Rates of Decomposition and Mineralization | p. 505 |
| Humus: Genesis and Nature | p. 512 |
| Composts and Composting | p. 515 |
| Direct Influences of Organic Matter on Plant Growth | p. 518 |
| Influence of Organic Matter on Soil Properties and the Environment | p. 519 |
| Management of Amount and Quality of Soil Organic Matter | p. 521 |
| Carbon Balance in the Soil-Plant-Atmosphere System | p. 524 |
| Factors and Practices Influencing Soil Organic Matter Levels | p. 526 |
| Soils and the Greenhouse Effect | p. 533 |
| Organic Soils (Histosols) | p. 537 |
| Conclusion | p. 539 |
| Study Questions | p. 540 |
| References | p. 541 |
| Nitrogen and Sulfur Economy of Soils | p. 543 |
| Influence of Nitrogen on Plant Growth and Development | p. 544 |
| Origin and Distribution of Nitrogen | p. 546 |
| The Nitrogen Cycle | p. 546 |
| Immobilization and Mineralization | p. 546 |
| Soluble Organic Nitrogen | p. 549 |
| Ammonium Fixation by Clay Minerals | p. 550 |
| Ammonia Volatilization | p. 551 |
| Nitrification | p. 552 |
| The Nitrate Leaching Problem | p. 553 |
| Gaseous Losses by Denitrification | p. 559 |
| Biological Nitrogen Fixation | p. 564 |
| Symbiotic Fixation with Legumes | p. 566 |
| Symbiotic Fixation with Nonlegumes | p. 570 |
| Nonsymbiotic Nitrogen Fixation | p. 572 |
| Addition of Nitrogen to Soil in Precipitation | p. 572 |
| Reactions of Nitrogen Fertilizers | p. 573 |
| Practical Management of Soil Nitrogen in Agriculture | p. 574 |
| Importance of Sulfur | p. 575 |
| Natural Sources of Sulfur | p. 578 |
| The Sulfur Cycle | p. 581 |
| Behavior of Sulfur Compounds in Soils | p. 583 |
| Sulfur Oxidation and Reduction | p. 584 |
| Sulfur Retention and Exchange | p. 586 |
| Sulfur and Soil Fertility Maintenance | p. 587 |
| Conclusion | p. 589 |
| Study Questions | p. 589 |
| References | p. 590 |
| Soil Phosphorus and Potassium | p. 592 |
| Role of Phosphorus in Plant Nutrition and Soil Fertility | p. 593 |
| Effects of Phosphorus on Environmental Quality | p. 595 |
| The Phosphorus Cycle | p. 601 |
| Organic Phosphorus in Soils | p. 604 |
| Inorganic Phosphorus in Soils | p. 606 |
| Solubility of Inorganic Phosphorus in Acid Soils | p. 609 |
| Inorganic Phosphorus Availability at High pH Values | p. 612 |
| Phosphorus-Fixation Capacity of Soils | p. 613 |
| Plant Genetics and Phosphorus Availability | p. 618 |
| Practical Control of Phosphorus in Soils | p. 619 |
| Potassium: Nature and Ecological Roles | p. 621 |
| Potassium in Plant and Animal Nutrition | p. 622 |
| The Potassium Cycle | p. 623 |
| The Potassium Problem in Soil Fertility | p. 627 |
| Forms and Availability of Potassium in Soils | p. 629 |
| Factors Affecting Potassium Fixation in Soils | p. 631 |
| Practical Aspects of Potassium Management | p. 633 |
| Conclusion | p. 634 |
| Study Questions | p. 635 |
| References | p. 635 |
| Micronutrients and Other Trace Elements | p. 638 |
| Deficiency Versus Toxicity | p. 639 |
| Role of the Micronutrients | p. 640 |
| Source of Micronutrients | p. 642 |
| General Conditions Conducive to Trace Element Deficiency/Toxicity | p. 644 |
| Factors Influencing the Availability of the Trace Element Cations | p. 646 |
| Organic Compounds as Chelates | p. 651 |
| Factors Influencing the Availability of the Trace Element Anions | p. 654 |
| Need for Nutrient Balance | p. 660 |
| Trace Element Cleanup and Metal Hyperaccumulators | p. 662 |
| Soil Management and Micronutrient Needs | p. 662 |
| Conclusion | p. 666 |
| Study Questions | p. 667 |
| References | p. 667 |
| Practical Nutrient Management | p. 669 |
| Goals of Nutrient Management | p. 670 |
| Environmental Quality | p. 673 |
| Nutrient Resources and Cycles | p. 684 |
| Recycling Nutrients through Animal Manures | p. 690 |
| Industrial and Municipal By-Products | p. 696 |
| Practical Utilization of Organic Nutrient Sources | p. 701 |
| Inorganic Commercial Fertilizers | p. 703 |
| Fertilizer Application Methods | p. 710 |
| Timing of Fertilizer Application | p. 715 |
| Diagnostic Tools and Methods | p. 716 |
| Soil Analysis | p. 720 |
| Site-Specific Nutrient Management | p. 725 |
| Site-Index Approach to Phosphorus Management | p. 727 |
| Broader Aspects of Fertilizer Practice | p. 733 |
| Conclusion | p. 736 |
| Study Questions | p. 736 |
| References | p. 737 |
| Soil Erosion and Its Control | p. 740 |
| Significance of Soil Erosion and Land Degradation | p. 741 |
| On-Site and Off-Site Effects of Accelerated Soil Erosion | p. 745 |
| Mechanics of Water Erosion | p. 750 |
| Models to Predict the Extent of Water-Induced Erosion | p. 753 |
| Factors Affecting Interrill and Rill Erosion | p. 754 |
| Conservation Tillage | p. 763 |
| Vegetative Barriers | p. 768 |
| Control of Gully Erosion and Mass Wasting | p. 770 |
| Control of Accelerated Erosion on Range and Forest Land | p. 772 |
| Erosion and Sediment Control on Construction Sites | p. 775 |
| Wind Erosion: Importance and Factors Affecting It | p. 779 |
| Predicting and Controlling Wind Erosion | p. 783 |
| Land Capability Classification as a Guide to Conservation | p. 787 |
| Progress in Soil Conservation | p. 789 |
| Real Value of Soil Conservation | p. 792 |
| Conclusion | p. 793 |
| Study Questions | p. 793 |
| References | p. 794 |
| Soils and Chemical Pollution | p. 796 |
| Toxic Organic Chemicals | p. 797 |
| Kinds of Organic Contaminants | p. 800 |
| Behavior of Organic Chemicals in Soil | p. 801 |
| Effects of Pesticides on Soil Organisms | p. 808 |
| Remediation of Soils Contaminated with Organic Chemicals | p. 810 |
| Contamination with Toxic Inorganic Substances | p. 818 |
| Potential Hazards of Chemicals in Sewage Sludge | p. 821 |
| Reactions of Inorganic Contaminants in Soils | p. 823 |
| Prevention and Elimination of Inorganic Chemical Contamination | p. 825 |
| Landfills | p. 827 |
| Radionuclides in Soil | p. 832 |
| Radon Gas from Soils | p. 834 |
| Conclusion | p. 837 |
| Study Questions | p. 837 |
| References | p. 837 |
| Geographic Soils Information | p. 840 |
| Soil Spatial Variability in the Field | p. 840 |
| Techniques and Tools for Mapping Soils | p. 845 |
| Modern Technology for Soil Investigations | p. 849 |
| Remote Sensing Tools for Soils Investigations | p. 850 |
| Air Photos | p. 852 |
| Satellite Imagery | p. 856 |
| Soil Surveys | p. 859 |
| The County Soil Survey Report and Its Utilization | p. 861 |
| Geographic Information Systems | p. 863 |
| GIS, GPS, and Site-Specific Agriculture | p. 866 |
| Conclusion | p. 869 |
| Study Questions | p. 869 |
| References | p. 869 |
| Global Soil Quality as Affected by Human Activities | p. 871 |
| The Concept of Soil Quality/Soil Health | p. 872 |
| Soil Resistance and Resilience | p. 876 |
| Sustaining Biological Productivity | p. 877 |
| The Population Explosion | p. 878 |
| Intensified Agroecosystems--The Green Revolution | p. 879 |
| Effects of Intensified Agroecosystems on Soil Quality or Health | p. 880 |
| Forced Production Intensification | p. 884 |
| Prospects for the Future | p. 887 |
| Modified Intensive Agroecosystems | p. 890 |
| Improving Low-Yielding Agricultural Systems | p. 893 |
| Improving Soil Quality in sub-Saharan Africa | p. 893 |
| Improving Soil Quality in Asia and Latin America | p. 899 |
| Conclusion | p. 900 |
| Study Questions | p. 900 |
| References | p. 901 |
| Canadian and FAO Soil Classification Systems | p. 903 |
| SI Units, Conversion Factors, and Periodic Table of the Elements | p. 907 |
| Glossary | p. 911 |
| Index | p. 937 |
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