Blue green algae(Cyanobacteria) are free-living as well as symbiotic microorganism. It is mainly recommended for wetland rice cultivation. It fixes about 25-30 kg/ha nitrogen under ideal conditions.

A composite culture of blue green algae is given as primary inoculum in trays. This is multiplied and applied as soil based flakes. The use of this bio fertilizer is not recommended in acidic soils with pH below 6.0.

It is also available as carrierbased inoculum.The inoculum is broadcasted directly in the rice fields @ 10 kg/ha one week after transplanting the seedlings.

Topdressing with rockphosphate 25kg/ha 10 days after inoculation of BGA will enhance its growth under field conditions