Emission Greenhouse gases 3 Meteorology and Climate 3 Air pollutants 2 Air pollution 2 Climatic change 2 Grasslands 2 Pollution and Degradation 2 Soil Chemistry and Mineralogy 2 Absorption 1 Air quality 1 Aquatic Biology and Ecology 1 Aquatic environment 1 Beef cattle 1 Cattle 1 Climatic changes 1 Climatic factors 1 Cotton 1 Crop production 1 Crop yield 1 Crop yields 1 Crops and climate 1 Cycling 1 Dairy farming 1 Ecosystems 1 Effluent 1 Electrons 1 Environmental factors 1 Environmental impact 1 Field Crops, (New March 2000) 1