Nitrogen cycle Carbon cycle 3 Nitrification 2 Plant-soil relationships 2 Plants 2 Air pollutants 1 Air pollution 1 Air quality 1 Aquatic Biology and Ecology 1 Aquatic environment 1 Beef cattle 1 Biochemistry and Physiology of Microorganisms, (New March 2000) 1 Biom�edecine 1 Biotechnology in pollution preventation 1 Carbon cycle (Biogeochemistry) 1 Cattle 1 Chemistry 1 Coastal ecology 1 Cycling 1 Dairy farming 1 Denitrification 1 Ecological interrelationships 1 Ecology 1 Effect of nitrogen on 1 Emission 1 Environmental 1 Environmental impact 1 Epidemiology 1 Genetics and Molecular Biology of Microorganisms, (New March 2000) 1 Genome analysis 1