Question

Define Biofertilizer

Answer 1

Bio fertilisers
Organisms that enrich the soil with nutrients are called bio-fertilisers. Bio fertilisers are used for specific crop plants such as pulses, legumes, oilseeds and rice. Bio fertilisers are renewable and non-pollutant sources of plant nutrients such as nitrogen. They are not alternatives to chemical fertilisers but can play a supplementary role in supplying nitrogen to specific crops under specific soil conditions.

Two bio fertilisers, Rhizobium and blue-green algae (Nostoc and Anabaena) are being used in cultivating pulses, legumes, oilseeds and wet-land rice.
Some of the biofertilisers are given below :

• Legume (Rhizobium symbiosis).
• Azolla (Anabaena symbiosis).
• Free-living bacteria (Azotobacter) live in the soil.
• Cyanobacteria (Anabaena, Nostoc).
• Mycorrhiza (symbiotic association of fungi with roots of higher plants).