What are biofertilizers? Describe their role in agriculture. Why are they preferred to chemical fertilizers?
Biofertilisers are the living organisms that promote the growth of plants by replenishing the nutrients in the soil. These include bacteria, fungi and cyanobacteria.
Role of biofertilisers in agriculture
Some biofertilisers such as Rhizobuim bacteria live in symbiotic association with plants. They live within the root nodules of leguminous plants. These bacteria fix atmospheric nitrogen and enrich the nitrogen content of soil.
Fungi such as Glomus also form symbiotic associations with plants (mycorrhiza) by absorbing phosphorus and passing it to plants.
- Cyanobacteria such as Nostoc and Anabaena also fix atmospheric nitrogen and act as biofertilisers, especially in paddy fields.
Biofertilisers are preferred over chemical fertilisers because of the following reasons:
- Biofertilisers are eco-friendly, while chemical fertilisers cause soil pollution in the long run.
- Biofertilisers contain living organisms, while certain chemical fertilisers have high acid content and might also contain heavy metals that can negatively affect soil ecology.
- Biofertilisers are a natural way of improving soil fertility.