Question

Free living bacteria in the soil play a key role in the process of nitrogen cycle in nature. Justify this statement.

Answer 1

Rhizobium is free living in soil but as symbionts can fix atmospheric nitrogen. It forms symbiotic association with roots of legumes to fix nitrogen.
Azotobacter is another free living nitrogen fixing bacteria. These bacteria play a vital role in nitrogen cycle as they fix the nitrogen in the soil and make it available for plant use.