The elements are naturally available in the soil by the decaying action of microorganisms. When leguminous plants are grown in fields, the microorganisms that harbour in the root nodules fixes atmospheric nitrogen to the soil, bacteria, fungi, algae, termite, earthworm, etc., increase the fertility of the soil. To access these nutrients, plants are dependent on the growth of soil microbes such as bacteria and fungi, which possess the metabolic machinery to depolymerize and mineralize organic forms of N, P, and S. Microbes with the plants include the nutrients supply to crops, plant growth stimulation, producing phytohormones, biocontrol of phytopathogens, improving soil structure, bioaccumulation of inorganic compounds, and bioremediation of metal-contaminated soils

Beneficial microorganisms include those that create symbiotic associations with plant roots (rhizobia, mycorrhizal fungi, actinomycetes, diazotrophic bacteria), promote nutrient mineralization and availability, produce plant growth hormones, and are antagonists of plant pests, parasites or diseases. Microorganisms are essential to soil formation and soil ecology because they control the flux of nutrients to plants (i.e., control of carbon, nitrogen, and sulfur cycles,), promote nitrogen fixation, and promote soil detoxification of inorganic and naturally occurring organic pollutants. Microorganisms are essential to soil formation and soil ecology because they control the flux of nutrients to plants (i.e., control of carbon, nitrogen, and sulfur cycles,), promote nitrogen fixation, and promote soil detoxification of inorganic and naturally occurring organic pollutants. Increasing levels of organic matter aid in soil structure, water-holding capacity, nutrient mineralization, biological activity, and water and air infiltration rates. Soil organic matter is the single most important soil property that can be influenced through management practices. Microorganisms play an important role in the acquisition and transfer of nutrients in soil.In particular, microorganisms can solubilise and mineralize P from inorganic and organic pools of total soil P. Soil microbes play a vital role in the sustained growth of plants. They decompose and recycling nutrients bound in organic materials. They help access minerals in rocks large and small. And, they can even refine nitrogen from the air into a useful form for plants. Soil organisms play a principal role in modification of their environment, nutrient cycling and soil formation. These effects can be achieved by contribution of soil biota to food webs which facilitates mineralization of soil organic matter and release of nutrients.