Rangeland soil biota affect soil properties and processes that control the availability of water and nutrients that are essential for the maintenance of productivity and vegetation composition. oil processes mediated by soil biota include decomposition, nutrient immobilization and mineralization, storage and release of water and nutrients, nitrogen fixation and denitrification, production of plant growth factors and nutrient uptake by mycorrhizae. oil biotic processes control aggregate creation and maintenance, soil macropore formation, and spatial-temporal patterns of soil organic matter and nutrients.