How do biofertilizers enrich the soil?
Biofertilizers play a vital role to solve the problems of soil fertility and soil productivity. Anabaena azollae, a cyanobacterium, lives in symbiotic association with the free-floating water fern, Azolla. The symbiotic system Azolla-Anabaena complex is known to contribute 40-60 mg N ha-1 per rice crop. In addition to this, cyanobacteria add organic matter, secretes growth-promoting substances like auxins and vitamins, mobilizes insoluble phosphate, and thus improves the physical and chemical nature of the soil. Rhizobium Leguminoserum and Azospirillum fix atmospheric nitrogen as nitrates and nitrites. Mycorrhizae formed by an association of bacteria and roots of higher plants increase soil fertility.
