Question

Name any two bacterial biofertilizers.

Answer 1

Bacterial biofertilizers are :

a. Rhizobium:

1. Rhizobia are rod-shaped, motile, aerobic, gram-negative, non-spore-forming, nitrogen-fixing bacteria containing Nod genes and Nif genes.
2. They form symbiotic associations with the roots of leguminous plants.
3. They bring about nodule formation on the roots and multiply inside the nodule.
4. They fix atmospheric nitrogen into organic forms, which can be used by plants as nutrients.
5. For e.g. R. leguminosarum is specific to pea and R. phaseoli to beans.

b. Azotobacter:

1. It is the important and well-known free-living, nitrogen-fixing, aerobic, non-photosynthetic, non-nodule forming bacterium, intimately associated with roots of grasses and certain plants.
2. It is used as a bio-fertilizer for all non-leguminous plants especially rice, cotton, vegetables, etc.

c. Azospirillum:

1. It is a free-living, aerobic nitrogen-fixing bacterium associated with roots of corn, wheat, and jowar.
2. It fixes the considerable quantity of nitrogen (20-40kg N/ha) in non–leguminous plants such as cereals, millets, cotton, oilseed, etc.