Preface xii
1 Cover Crops and Soil Ecosystem Services 1
1.1 Cover Crops 1
1.2 Soil Ecosystem Services 4
1.3 Cover Crops and Soil Ecosystem Services 6
1.4 Summary 8
References 9
2 Cover Crop Biomass Production 12
2.1 Cover Crops and Biomass 12
2.2 Aboveground Biomass Production 13
2.2.1 Temperate Regions 13
2.2.2 Semiarid Temperate Regions 14
2.2.3 Tropical and Subtropical Regions 15
2.3 Belowground Biomass Production 17
2.4 Threshold Level of Biomass Production 18
2.5 Management Practices that Affect Biomass Production 18
2.5.1 Planting Early 19
2.5.1.1 Interseeding 19
2.5.1.2 Planting after Summer Crop Harvest 21
2.5.1.3 Planting after Corn Silage or Short- Growing Season Crop Harvest 23
2.5.2 Terminating Late 23
2.5.3 Cover Crop Mixes 25
2.5.4 Seeding Rate 26
2.5.5 Planting Method 26
2.5.6 Tillage and Cropping Systems 27
2.5.7 Soil Texture and Number of Years in Cover Crops 28
2.5.8 Irrigation and Fertilization 28
2.6 Summary 29
References 30
3 Soil Health 35
3.1 Soil Health 35
3.2 Cover Crops and Soil Health 37
3.2.1 Soil Physical Properties 37
3.2.1.1 Soil Compaction 37
3.2.1.2 Soil Structure 39
3.2.1.3 Water Infiltration 40
3.2.1.4 Temperature 42
3.2.2 Soil Chemical Properties 42
3.2.3 Soil Biological Properties 43
3.2.3.1 Microorganisms 44
3.2.3.2 Macroorganisms 45
3.3 Interconnectedness of Soil Health Parameters 47
3.4 Managing Soil Health 47
3.4.1 Biomass Production 48
3.4.2 Time after Cover Crop Introduction 48
3.4.3 Cover Crop Species and Mixes 49
3.4.4 Tillage System 50
3.4.5 Initial Soil Condition 51
3.5 Summary 51
References 52
4 Water Erosion 58
4.1 Overview 58
4.2 Runoff 59
4.3 Sediment Loss 62
4.4 Nutrient Loss 63
4.5 Soil Carbon Loss 63
4.6 A Leading Factor of Water Erosion: Biomass Production 64
4.7 Cover Crops and Erosion- Prone Systems 65
4.7.1 Low- Biomass Producing Cropping Systems 66
4.7.2 Corn Silage and Seed Corn 66
4.7.3 Crop Residue Removal 68
4.7.4 Orchard Crops 68
4.8 Summary 69
References 69
5 Wind Erosion 73
5.1 Extent of Wind Erosion 73
5.2 Soil Loss 74
5.3 Soil Erodibility 76
5.4 Managing Wind Erosion 78
5.4.1 Biomass Production 78
5.4.2 Cover Crop Species 79
5.4.3 Growth Stage and Seeding Rate 80
5.4.4 Crop and Tillage Systems 81
5.4.5 Climate 82
5.5 Summary 82
References 83
6 Nutrient Losses 85
6.1 Implications of Nutrient Losses 85
6.2 Nutrient Leaching 86
6.3 Dissolved Nutrients in Runoff 89
6.4 Nutrient Release from Cover Crops 90
6.5 Management Implications 92
6.6 Nutrient Stratification 93
6.7 Summary 94
References 94
7 Soil Gas Emissions 97
7.1 Carbon and Nitrogen Emissions 97
7.2 Carbon Dioxide 98
7.3 Nitrous Oxide 99
7.4 Methane 100
7.5 Factors Affecting Soil Gas Emissions 100
7.5.1 Cover Crop Species 101
7.5.2 Biomass Production 102
7.5.3 Nitrogen Fertilization 103
7.5.4 Tillage and Cropping System 104
7.5.5 Measurement Time 105
7.5.6 Soil Texture and Climate 106
7.6 Summary 106
References 107
8 Carbon Sequestration 109
8.1 The Need for Carbon Sequestration 109
8.2 Rates of Carbon Sequestration 110
8.3 Topsoil Versus Subsoil Carbon Sequestration 112
8.4 Managing Carbon Sequestration 114
8.4.1 Biomass Production 114
8.4.2 Cover Crop Species and Mixes 116
8.4.3 Years after Cover Crop Adoption 117
8.4.4 Initial Soil Carbon Level 118
8.4.5 Tillage Systems 119
8.4.6 Soil Texture 120
8.4.7 Topographic Characteristics 120
8.4.8 Climate 121
8.5 Cropping System Carbon Footprint 122
8.6 Strategies to Enhance Cover Crop Potential to Sequester Carbon 122
8.7 Summary 124
References 125
9 Soil Water 128
9.1 Soil Water Management 128
9.2 High Precipitation Regions 129
9.3 Low Precipitation Regions 129
9.4 Mechanisms of Soil Water Storage with Cover Crops 132
9.5 Water Management 134
9.5.1 Biomass Production 135
9.5.2 Timing of Cover Crop Termination 136
9.5.3 Tillage System 136
9.5.4 Soil Texture 137
9.6 Summary 138
References 138
10 Weed Management 141
10.1 Cover Crops and Weeds 141
10.2 Weed Suppression 142
10.3 Managing Weeds 144
10.3.1 Biomass Production and Surface Cover 145
10.3.2 Cover Crop Species and Mixes 146
10.3.3 Tillage System 148
10.3.4 Climate 148
10.4 Summary 149
References 150
11 Soil Fertility 151
11.1 Soil Fertility Management 151
11.2 Organic Matter 152
11.2.1 Nitrogen 154
11.2.2 Nitrogen Scavenging 154
11.2.3 Reduction of Nitrogen Losses 154
11.2.4 Nitrogen Fixation 155
11.3 Phosphorus 156
11.4 Other Nutrients 158
11.5 Soil pH 158
11.6 Cation Exchange Capacity 160
11.7 Carbon to Nitrogen Ratio 161
11.8 Summary 163
References 163
12 Crop Yields 167
12.1 Multi- functionality of Cover Crops 167
12.2 Crop Yields 168
12.3 Climate 169
12.3.1 Cool and Warm Climates 169
12.3.2 Water- Limited Regions 169
12.4 Factors Affecting Crop Production 170
12.4.1 Cover Crop Species 170
12.4.2 Nitrogen Fertilization 171
12.4.3 Biomass Production 171
12.4.4 Planting Time and Method 172
12.4.5 Termination Timing 174
12.4.6 Cover Crop Mixes 174
12.4.7 Years after Cover Crop Adoption 175
12.4.8 Tillage Systems 176
12.4.9 Soil Texture 176
12.5 Summary 177
References 177
13 Grazing and Harvesting 180
13.1 Cover Crop Biomass Removal 180
13.2 Grazing 181
13.2.1 Soil Compaction 181
13.2.2 Water Infiltration 184
13.2.3 Soil Carbon Dynamics and Sequestration 185
13.2.4 Crop Yields 186
13.3 Minimizing Potential Grazing Impacts 187
13.3.1 Amount of Biomass Removal 188
13.3.2 Stocking Rate 189
13.3.3 Years under Grazing 189
13.3.4 Tillage 190
13.3.5 Soil Water Content 190
13.4 Harvesting 191
13.5 Grazing and Harvesting: An Added Benefit from Cover Crops? 193
13.6 Summary 194
References 194
14 Economics 197
14.1 Cover Crops and Farm Profits 197
14.2 Economic Analysis 198
14.2.1 Grazing and Harvesting 199
14.2.2 Weed Suppression 201
14.2.3 Nitrogen Credit 202
14.2.4 Soil Carbon Credit 203
14.2.5 Crop Residue Harvesting 204
14.2.6 Valuation of Other Ecosystem Services 204
14.3 Site- Specificity of Economic Benefits 205
14.4 Summary 206
References 206
15 Adaptation to Extreme Weather 210
15.1 Extreme Weather Events 210
15.2 Droughts 211
15.3 Floods 212
15.4 Precipitation Extremes 214
15.5 Dust Storms 217
15.6 Temperature Extremes 217
15.7 Soil Resilience 218
15.8 Summary 220
References 221
16 Opportunities, Challenges, and Future of Cover Crops 224
16.1 Opportunities 224
16.1.1 Ecosystem Services 224
16.1.2 Biomass Production 227
16.1.3 Economics 228
16.1.4 Fluctuating Climates 229
16.2 Challenges 229
16.2.1 Ecosystem Services 230
16.2.1.1 Biomass Production 230
16.2.1.2 Soil Properties 231
16.2.1.3 Carbon Sequestration 232
16.2.1.4 Dissolved Nutrients 232
16.2.1.5 Crop Yields 233
16.2.1.6 Economics 233
16.2.1.7 Fluctuating Climates 234
16.3 Remaining Questions 234
16.4 The Future of Cover Crops 236
16.5 Summary 237
References 238
Appendix I: Common and Scientific Names Used in the Book 241
