Role of blue green algae in rice productivity.

Rice is one of the oldest cultivated crops and most staple food crop for more than a third of the world's population. It is the main cereal crop of Nepal. Nepal is importing chemical fertilizers from other countries for rice productivity. On the other hand transportation of fertilizers in hilly regions of Nepal is a difficult and expensive due to lack of transport. The inoculation of nitrogen fixing Blue Green Algal (BGA) is an alternative and sustainable source of nitrogen to increase the rice productivity. The mixed inoculum of Nostoc, Anabaena, Westiellopsis, Aulosira and Scytonema was used in field trial in 2005. The single inoculum of Anabaena was also used separately to compare the most effective treatment. The BGA inoculum with N: P: K (30:20:20 kg/ha) was found to be the most effective treatment for rice productivity.