Page 12 - Soil Degradation, Conservation and Remediation

Contents xi

3.4.10 Alley Cropping..................................................................... 93
3.4.11 Buffer Strips......................................................................... 94
3.4.12 Grassed Waterways.............................................................. 95
3.4.13 Terracing .............................................................................. 96
References................................................................................................... 99
4 Wind Erosion ............................................................................................. 103
4.1 Causes of Wind Erosion ..................................................................... 103
4.2 Effects of Wind Erosion ..................................................................... 104
4.3 Processes of Wind Erosion ................................................................. 105
4.3.1 Saltation............................................................................... 105
4.3.2 Suspension........................................................................... 106
4.3.3 Surface Creep....................................................................... 106
4.3.4 Abrasion............................................................................... 107
4.3.5 Sorting.................................................................................. 107
4.4 Factors Affecting Wind Erosion......................................................... 107
4.4.1 Soil....................................................................................... 108
4.4.2 Climate................................................................................. 109
4.4.3 Field Width and Slope.......................................................... 110
4.4.4 Vegetation ............................................................................ 110
4.5 Principles of Wind Erosion Control ................................................... 111
4.6 Wind Erosion Control Measures ........................................................ 112
4.6.1 Stabilization of Soil ............................................................. 112
4.6.2 Cover Crops......................................................................... 112
4.6.3 Ridging and Surface Roughening ........................................ 113
4.6.4 Residue Management........................................................... 114
4.6.5 Wind Barrier ........................................................................ 116
4.6.6 Strip Cropping ..................................................................... 117
4.7 Stabilization of Dunes ........................................................................ 118
References................................................................................................... 120

5 Chemical Soil Degradation ....................................................................... 125
5.1 Chemical Degradation of Soil and Its Extent .................................... 125
5.2 Loss of Nutrients and/or Organic Matter ........................................... 126
5.2.1 Leaching of Nutrients .......................................................... 127
5.2.2 Nutrient Loss due to Residue Burning ................................. 128
5.2.3 Nutrient Losses due to Erosion ............................................ 129
5.2.4 Crop Removal of Nutrients .................................................. 129
5.3 Acidifi cation ....................................................................................... 129
5.3.1 Causes of Soil Acidifi cation ................................................. 130
5.3.2 Effects of Soil Acidity .......................................................... 133
5.3.3 Management of Acidic Soils ................................................ 136
5.3.4 Acid Sulfate Soils ................................................................ 141
5.4 Soil Salinization ................................................................................ 142
5.4.1 Management of Saline Soils ................................................ 143
5.5 Salt-Tolerant Crops ............................................................................ 144
References................................................................................................... 146