Explanation

Cyanobacteria or blue-green algae is the most suitable source of biofertiliser, particularly in rice fields, $e.g.,$ Nostoc, Anabaena Rhizobium is a symbiotic bacterium that lives in the root nodules of legumes and fixes atmospheric nitrogen into organic compound Azospirillum and Azotobacter are free-living bacteria which absorb free nitrogen from soil, air and convert it into salts of nitrogen like amino acids and enrich soil nutrients