This contains bacteria Rhizobium sp. In symbiotic association with leguminous crops the bacteria fixes large quantity of atmospheric nitrogen and makes it available for plants.

Rhizobium normally enters the root hairs, multiply and form nodules producing nitrogenous compounds which are utilized by the plants.

It can fix up to 20-40 kg of nitrogen per acre in one cropping season and leaves behind substantial quantity of nitrogen in soil for succeeding crops and increases yield.