Biofertilizers are the cultures of microorganisms used for inoculating seed or soil or both under ideal conditions to increase the availability of plant nutrients. Some of the microorganisms have the beneficial role of bionitrogen fixation to supply nitrogen to crops, solubilizing insoluble phosphates to soluble forms to make them available to crops.
Synthesizing biomass for managing crops particularly rice and hasten the process of decomposition of cellulose in composts and farmyard manures through cellnlolytic organisms. These Biofertilizers can be divided into two groups – inoculants of specific organism such as Rhizobia, Azetobactor, Blue green algae, phosphate solubilizers, cellulorytic microorganisms and other group, that is biomass producing organisms e.g. Azola.
It has been observed that an increase yield to the extent of 10-15% could be obtained through algal application in the absence of nitrogenous fertilizers. Phosphate solubilizing microorganisms particularly the soil bacteria belonging to the genera pseudomonas and Bacillus and fungi belong to the genera Penicillium and Aspergillums possess the ability to transform insoluble phosphates into soluble forms. Azolla, a water form organism with nitrogen fixing Anabaena bacteria is a biological source of nitrogen in rice cultivation. This can be used as green manure prior to rice planting or the Azolla can be grown side by side with rice seedlings for some time and then incorporated in the soil.