Question

Materials of biological origin which are commonly used to maintain and improve soil fertility are

• A. green manures
• B. biofertilizers
• C. bioinsecticides
• D. both (a) and (b).

Answer 1

The correct option is D both (a) and (b).

Green manures are added to the soil to increase the productivity. Manures is of natural origin. The presence of nutrients in manure have a great role in increasing soil fertility. Biofertilizers are organisms which enrich the soil with nutrients e.g., Rhizobiumin symbiotic association with legume plants.