Write a note on Rhizobia as a biofertilizer.

Explanation

(1) Rhizobia (Singular-Rhizobium)is a Gram negative nitrogen fixing aerobic bacterium.
(2) It lives in symbiotic association with leguminous roots.
(3) Rhizobium provides fixed nitrogen to the host plant. The host plant in return provides food and water to the bacterium (Rhizobium).
(4) Rhizobiumfixes atmospheric nitrogen into nitrite and nitrate which are made available to the leguminous plants.
(5) These bacteria are host specific e.g. R. Phaseoli for beans.
(6) In a laboratory, pure cultures of specific Rhizobiumspecies are raised which are used for the preparation of biof ertilizer.