Nitrification 8 Denitrification 3 Genetics and Molecular Biology of Microorganisms, (New March 2000) 2 Nitrogen 2 Nitrogen cycle 2 Nitrogen fixation 2 Nitrogen fixing bacteria 2 Nodulation 2 Plant-soil relationships 2 Plants 2 Root nodules 2 Soil Biology 2 Soils 2 Agricultural microbiology 1 Algae 1 Bacteria 1 Biochemistry and Physiology of Microorganisms, (New March 2000) 1 Biogeochemistry 1 Denitrifying microorganisms 1 Ectomycorrhizas 1 Effect of nitrogen on 1 Endomycorrhizas 1 Fixation 1 Fungi 1 Gene expression 1 Genetic markers 1 Genome analysis 1 Genomes 1 Genomics 1 Iron 1