Microorganisms help return minerals and nutrients back to the environment so that the materials can then be used by other organisms. microorganisms play a crucial role in this recycling. They are responsible for breaking down dead matter and releasing materials back to the environment. Microorganisms play an important role in improving soil fertility and involved in all aspects of N cycling, including N2 fixation, nitrification, denitrification and ammonification. They decompose plant residues, soil organic matter and release inorganic nutrients that can then be taken up by plants. which changes plant nutrients to readily available forms and make and stabilize desirable soil structure for luxuriant plant growth Phosphorus Solubilizing bacteria and fungi play an important role in converting insoluble phosphatic.