Q. 51 What are biofertilisers? Give two examples.

Biofertilisers are organisms that enrich the nutrient quality of the soil. The main source of biofertiizers are bacteria, fungi and cyanobacteria

(i) Azospirilium, Rhizobium and Azotobacter can fix atmospheric nitrogen in the soil

(ii) Blue-green algae like Anabaena, Nostoc, Occilatoria add organic matter to the soil and responsible for increase its fertility.