Biofertilisers: Organisms which enrich the soil with nutrients are called biofertilisers. Biofertilisers are used for the specific crop plants such as pulses, legumes, oil seeds and rice. They are renewable and non-pollutant sources of plant nutrient such as nitrogen.
Nitrogen fixing microorganisms, i.e., non-symbiotic and symbiotic cyanobacteria and phosphate-solubilising microorganism are the main type of biofertilisers.