Preface ......................................................... v
Introduction .................................................... 1
Chapter 1. Carbon and Nitrogen Pools in Terrestrial
Ecosystems ........................................... 5
1.1. Forms and Quantities of Carbon and Nitrogen
on Earth ................................................... 5
1.1.1. Carbon .............................................. 5
1.1.2. Nitrogen ............................................ 7
1.2. Carbon and Nitrogen in Terrestrial Phytomass ............... 8
1.2.1. Estimates of Phytomass С and N Stocks for
Natural Ecosystem Types ............................. 9
1.2.2. Estimates for Agroecosystems ....................... 20
1.2.3. Net Primary Production and Phytomass Stocks
in Different Climatic Zones ........................ 21
1.3. Carbon and Nitrogen in Soils .............................. 22
1.3.1. Global Soil Organic Carbon and Nitrogen
Pools .............................................. 22
1.3.2. Global Soil Inorganic Carbon and Nitrogen
Pools .............................................. 36
1.4. Global Vegetation-Soil Organic Matter
Interrelationships ........................................ 41
Chapter 2. Carbon and Nitrogen Cycles in Terrestrial
Ecosystems .......................................... 45
2.1 The Global Carbon Cycle .................................... 45
2.1.1. Biosphere-Atmosphere Exchange
of Carbon Dioxide .................................. 45
2.1.2. Biosphere-Atmosphere Exchange of Methane,
Carbon Monoxide and Other C-Containing
Gases .............................................. 47
2.1.3. Ocean-Atmosphere Exchange of Carbon
Dioxide ............................................ 47
2.1.4. Transport of Carbon to Oceans via Fluvial
Systems ............................................ 48
2.2. The Global Nitrogen Cycle ................................. 49
2.2.1. N2 Fixation by Lightning ........................... 49
2.2.2. Biological N2 Fixation ............................. 49
2.2.3. Ammonia Production with the Haber-Bosch
Process ............................................ 51
2.2.4. Atmospheric N Depositions .......................... 52
2.2.5. Emissions of NOx, N2O, N2,
NH3 and Organic N .................................. 54
2.2.6. Leaching of Nitrogen to Groundwater ................ 55
2.2.7. Transport of Nitrogen to Oceans by Rivers .......... 55
2.2.8. Ocean N Budgets .................................... 56
2.2.9. Summary of the Major Global N Fluxes ............... 57
2.3. Carbon and Nitrogen Cycling in Soils ...................... 58
2.3.1. Carbon and Nitrogen Cycling in Upland Soils ........ 59
2.3.2. Carbon and Nitrogen Cycling in Wetland Soils ....... 73
2.4. Global Climate Change and С and N Cycling ............ 79
Chapter 3 Soil Organic Matter Characterization ................. 81
3.1. Chemical Characterization of Soil Organic Matter .......... 82
3.1.1. Non-Humic Substances ............................... 83
3.1.2. Humic Substances ................................... 85
3.2. Physical Characterization of Soil Organic Matter .......... 97
3.2.1. Particulate Organic Matter ......................... 98
3.2.2. Organomineral Complexes ........................... 100
3.3. Morphological Characterization of Soil
Organic Matter ........................................... 104
3.3.1. Classification of Terrestrial Humus Forms ......... 104
3.3.2. Characterization of Terrestrial Humus Forms ....... 106
3.3.3. Humus Form Development in a Forest
Succession ........................................ 110
3.3.4. Ecological Features of Humus Forms ................ 110
Chapter 4 Organic Matter and Soil Quality ..................... 113
4.1. Soil Quality ............................................. 114
4.1.1 Definition and Concept ............................. 114
4.2. Impact of SOM on Soil Physical, Chemical
and Biological Properties ................................ 117
4.2.1. Physical Properties ............................... 118
4.2.2. Chemical Properties ............................... 122
4.2.3. Biological Properties ............................. 126
4.3. Evaluation of Organic Components as Soil
Quality Indicators ....................................... 130
4.3.1. Soil Organic Matter ............................... 130
4.3.2. Soil Microbial Biomass ............................ 132
4.3.3. Soil Enzymes ...................................... 132
4.4 Use of Combined Biological Parameters for Soil
Quality Estimation ....................................... 133
4.4.1. Indexes Developed from Two Measured Parameters .... 133
4.4.2. Indexes Developed from More than Two
Measured Parameters ............................... 134
Chapter 5 Carbon and Nitrogen Transformations in Soils ........ 137
5.1. Transformations of Organic Components .................... 138
5.1.1. Methods of Mineralization-Immobilization
Measurement ....................................... 139
5.1.2. Mineralization-Immobilization Measurements
in the Field ...................................... 142
5.1.3. Results from 15N Field Studies .................... 145
5.1.4. Long-Term С and N Mineralization
and Accumulation .................................. 148
5.2. Transformations of Inorganic Components .................. 148
5.2.1. Formation of Secondary Carbonates ................. 148
5.2.2. Nitrification ..................................... 152
5.2.3. Fixation and Defixation of Ammonium ............... 156
Chapter 6. Anthropogenic Activities and Soil Carbon
and Nitrogen ....................................... 161
6.1. Land Use Changes ......................................... 161
6.1.1. Land Use Area Distribution
and Its Global Change ............................. 161
6.1.2. Change in SOC and SON Following Land
Conversion ........................................ 172
6.1.3. Land Use Changes and Greenhouse
Gas Emissions ..................................... 187
6.1.4. Fire Regimes ...................................... 192
6.2. Agricultural Management .................................. 194
6.2.1. Soil Tillage ...................................... 194
6.2.2. Fertilization ..................................... 200
6.2.3. Introduction of Fallow Systems .................... 205
6.2.4. Crop Rotation Effects ............................. 207
6.3. Ecosystem Disturbance .................................... 209
6.3.1. Erosion and Deposition Effects .................... 209
6.3.2. Mine Spoil Reclamation ............................ 212
6.3.3. Salinization ...................................... 214
6.3.4. Soil Acidification ................................ 214
Chapter 7. Leaching Losses and Groundwater Pollution .......... 219
7.1. Dissolved Organic Carbon ................................. 220
7.2. Dissolved Organic Nitrogen ............................... 223
7.3. Nitrate Leaching ......................................... 226
7.3.1 Reducing Leaching Losses ........................... 230
Chapter 8 Bidirectional Biosphere-Atmosphere Interactions ..... 235
8.1. Atmospheric Nitrogen Depositions ......................... 236
8.1.1. Wet and Dry Deposition ............................ 236
8.1.2. Effect of N Deposition on Ecosystems .............. 240
8.2. Carbon Fixation via Photosynthesis ....................... 243
8.2.1. Photosynthetic Pathways ........................... 243
8.2.2. Global Distribution of C, and C4 Pathways ......... 244
8.2.3. Response of C3 and C4 Pathways to Increasing
Atmospheric C02 Concentration ..................... 245
8.3. Biological N2 Fixation ................................... 246
8.3.1. N2 Fixation by Non-symbiotic Bacteria ............. 247
8.3.2. N2 Fixation by Symbiotic Bacteria ................. 248
8.3.3. Global Estimates of Biological N2 Fixation ........ 250
8.4. Carbon Dioxide Emission .................................. 251
8.4.1. Carbon Dioxide Emissions from Biomass
Burning and Soils ................................. 254
8.4.2. Carbon Dioxide Emission Mitigation Options ........ 255
8.4.3. Role of Forests in C02 Mitigation ................. 256
8.4.4. Potential for С Sequestration by Agriculture ...... 260
8.5. Methane Emission ......................................... 265
8.5.1. Methane Emission from Rice Agriculture ............ 268
8.5.2. Methane Production in Rice Soils .................. 269
8.5.3. Factors Regulating Methane Emission
from Rice Fields .................................. 271
8.5.4. Mitigation Options for Agricultural Emission
of Methane ........................................ 273
8.6. Emission of Oxides of Nitrogen: N2O and NO ............... 276
8.6.1. Nitrous Oxide Emissions ........................... 276
8.6.2. Nitric Oxide Emissions ............................ 281
8.6.3. Factors Regulating Emission of N20 and NOx ........ 284
8.6.4. Nitrogen Oxide Emission Mitigation Options ........ 291
8.7. Ammonia Emission ......................................... 291
8.7.1. Ammonia Emission Mitigation Options ............... 294
8.7.2. Ammonia Emission from Plants ...................... 294
8.8. Global Climate Change and Crop Yields .................... 295
8.8.1. Projected Demand of Crop Yields ................... 295
8.8.2. Influence of Climate Change on Crop Yields ........ 296
8.8.3. Potential to Increase Global Production ........... 297
8.9. Economics of Carbon Sequestration ........................ 298
8.9.1. Methods for Calculating Carbon
Sequestration Costs ............................... 299
8.9.2. Economics of Carbon Sequestration
in Forestry ....................................... 301
8.9.3. Economics of Carbon Sequestration
in Agriculture .................................... 304
8.9.4. Secondary Benefits from Carbon Sequestration
Measures .......................................... 304
8.9.5. Leakage of Emissions Beyond Project
Boundaries ........................................ 305
Chapter 9. Modeling Carbon and Nitrogen Dynamics in the
Soil-Plant-Atmosphere System ....................... 307
9.1. Carbon Dioxide Exchange from Soils ....................... 307
9.2. Methane Emissions from Rice Fields
and Natural Wetlands ..................................... 312
9.2.1 Oxidation of Atmospheric Methane in Soils .......... 317
9.3. Nitrogen Trace Gas Emission .............................. 317
9.4. Modeling Nitrogen Dynamics in Soils ...................... 324
9.4.1. Denitrification ................................... 324
9.4.2. Ammonia Volatilization ............................ 325
9.4.3. Nitrate Leaching .................................. 327
9.4.4. Nitrogen Mineralization Kinetics .................. 328
9.4.5. Nitrification ..................................... 333
9.5. Modeling Organic Matter Dynamics in Soils ................ 333
9.5.1. Measured Versus Functional Soil Organic
Matter Pools ...................................... 337
9.5.2. Classification of Models .......................... 339
9.5.3. Evaluation and Use of Soil Organic Matter
Models ............................................ 340
References .................................................... 343
Index ......................................................... 417
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