Rhizobium - Symbiotically Fix atmospheric nitrogen into organic forms which can be used by the plant as nutrients Azospirullum / Azotobacter - free living bacteria fix atmospheric nitrogen Glomus / Fungi - Symbiotic with plants absorbs phosphorus from soil and passes it to plant Cyanobacteria / Anabaena / Nostoc / Oscillatoria - fix atmospheric nitrogen in acquatic and terrestrial environment Blue green algae - add organic matter to soil and increase soil fertility
