Question

Name one 'biological nitrogen-fixer'.

Answer 1

Rhizobium bacteria

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Answer 2

Rhizobium bacteria is a biological fixer of atmospheric nitrogen.

Explanation:

The system of cultivating a leguminous crop between two cereals crops is called crop rotation. Crop rotation is very helpful for the soil because it improves the fertility of the soil by replenishing it with nitrogen and increases the production of food grains. Leguminous plants contain the Rhizobium bacteria which are present in the root nodules of the plant. These bacteria can fix atmospheric nitrogen in the soil . Thus the next crop will require less amount of nitrogen fertilizer.