farmer authorities the Azobaceter, Clostridium and other microorganisms to accumulate nitrogen from the air by allowing a field to lie unseeded or unplanted. Nitrogen of the commercial fertilizers are very costly. Symbiotic Nitrogen Fixation: The knots on the roots of leguminous plants (i.e., clover, beans, peas, alfalfa) contain bacteria belonging to the genus Rhizobium. While growing together with the plants, this genus Rhizobium gathers nitrogen from the air and combines it into substances essential