Microbes increase soil fertility. They're used as a biofertilizer in agriculture. Microbes decompose dead and decaying organic matter and help with the recycling of nutrients. Microorganisms help in organic matter decomposition, humus formation. The important role of microorganisms includes – Nitrogen fixation, phosphate solubilisation, potassium mobilization, antagonism towards pathogens, pests. Hence, the role of microorganisms in agriculture is indispensable. They decompose dead organic matter. This substance when mixed with the soil will make it fertile. Some microorganisms like Rhizobium form symbiotic associations with plants and form root nodules. These organisms fix atmospheric nitrogen and supply it to plants.