Nitrogen fixing bacteria Soil Biology 4 Nitrogen fixation 3 Biochemistry and Physiology of Microorganisms, (New March 2000) 2 Denitrification 2 Endomycorrhizas 2 Forests and Forest Trees (Biology and Ecology) 2 Genetics and Molecular Biology of Microorganisms, (New March 2000) 2 Microbial Ecology, (New March 2000) 2 Mycorrhizal fungi 2 Mycorrhizas 2 Nitrification 2 Nitrogen 2 Nitrogen fixing trees 2 Nodulation 2 Plants 2 Root nodules 2 Soil microbiology 2 Trees 2 Vesicular arbuscular mycorrhizas 2 Woody plants 2 Agricultural microbiology 1 Agroforestry 1 Agroforestry and Multipurpose Trees: Community, Farm and Social Forestry 1 Animal Ecology 1 Arthropod communities 1 Azolla 1 Biodiversity 1 Biogeochemistry 1 Biological Resources (Animal) 1