Table of Contents
The Chemical Composition of Soils 3
Elemental Composition 3
Metal Elements in Soils 8
Solid Phases in Soils 11
Soil Air and Soil Water 16
Soil Mineral Transformations 17
For Further Reading 20
Problems 21
Balancing Chemical Reactions 25
Soil Minerals 28
Ionic Solids 28
Primary Silicates 36
Clay Minerals 41
Metal Oxides, Oxyhydroxides, and Hydroxides 49
Carbonates and Sulfates 54
For Further Reading 56
Problems 57
The Discovery of the Structures of Clay Minerals 59
Soil Humus 65
Biomolecules 65
Humic Substances 70
Cation Exchange Reactions 72
Reactions with Organic Molecules 77
Reactions with Soil Minerals 82
For Further Reading 85
Problems 86
Film Diffusion Kinetics in Cation Exchange 91
The Soil Solution 94
Sampling the Soil Solution 94
Soluble Complexes 96
Chemical Speciation 101
Predicting Chemical Speciation 104
Thermodynamic Stability Constants 110
For Further Reading 113
Problems 114
Mineral Stability and Weathering 119
Dissolution Reactions 119
Predicting Solubility Control: Activity-Ratio Diagrams 125
Coprecipitated Soil Minerals 130
Predicting Solubility Control: Predominance Diagrams 133
Phosphate Transformations in Calcareous Soils 135
For Further Reading 139
Problems 140
Oxidation-Reduction Reactions 144
Flooded Soils 144
Redox Reactions 148
The Redox Ladder 154
Exploring the Redox Ladder 159
pE-pH Diagrams 162
For Further Reading 165
Problems 166
Balancing Redox Reactions 169
The Invention of the pH Meter 171
Soil Particle Surface Charge 174
Surface Complexes 174
Adsorption 179
Surface Charge 181
Points of Zero Charge 183
Schindler Diagrams 188
For Further Reading 190
Problems 191
Soil Adsorption Phenomena 195
Measuring Adsorption 195
Adsorption Kinetics and Equilibria 197
Metal Cation Adsorption 203
Anion Adsorption 206
Surface Redox Processes 209
For Further Reading 214
Problems 214
Exchangeable Ions 219
Soil Exchange Capacities 219
Exchange Isotherms 223
Ion Exchange Reactions 226
Biotic Ligand Model 230
Cation Exchange on Humus 233
For Further Reading 238
Problems 239
Colloidal Phenomena 244
Colloidal Suspensions 244
Soil Colloids 248
Interparticle Forces 250
The Stability Ratio 255
Fractal Floccules 261
For Further Reading 266
Problems 267
Mass Fractals 271
Soil Acidity 275
Proton Cycling 275
Acid-Neutralizing Capacity 279
Aluminum Geochemistry 282
Redox Effects 286
Neutralizing Soil Acidity 288
For Further Reading 290
Problems 291
Measuring pH 293
Soil Salinity 296
Saline Soil Solutions 296
Cation Exchange and Colloidal Phenomena 298
Mineral Weathering 302
Boron Chemistry 305
Irrigation Water Quality 308
For Further Reading 311
Problems 312
Units and Physical Constants in Soil Chemistry 316
For Further Reading 319
Problems 319
Index 321
