How are biofertilisers different from fertilisers such as NPK that we buy from the market? Justify the role of rhizobium as a biofertiliser.

Explanation

Today environmental pollution is a major threat due to the thoughtless use of chemicals to meet the ever increasing demands of agricultural production. Due to the overuse of chemical fertilizers there is a large-pressure to switch to organic farming using biofertilizers. Biofertilizers are organisms that enrich the nutrient quality of the soil. The main sources of biofertilizers are bacteria, fungi and cyanobacteria. The root nodules of leguminous plants are formed by the symbiotic association of Rhizobium. These bacteria fix atmospheric nitrogen into organic forms, which is used by the plant as nutrient.