4. Isolation and characterization of strain Production of certified organism Production of commercial innoculant Innoculation Single innoculation Combined innoculation Field application

12. rhizobia N2N2 Symbiotic association with legumes and non legumes stimulatory root exudates and form nodules Neither the plant nor the bacteria can fix nitrogen when live separately The nodules filled with pink sap are called the effective nodules. maintain the rhythm of oxygen supply to the bacteria and helps the activity of nitrogenase enzyme. The nitrogenase is responsible for reduction of nitrogen to ammonia in the process of nitrogen fixation. The amount of atmospheric nitrogen fixed varies with the strains of rhizobium, plant species and environmental factors.

13. While chemical fertilizers are used to increase crop productivity, long-term usage could lead to weakening the roots of plants and making them easy prey to unwanted diseases. Biofertilizers, on the other hand, help the soil to remain fertile and strong.