Question

Nitrogen is essential nutrient for plant growth,but farmers who cultivate pulse crop like green,Bengal gram, black gram etc. do not apply nitrogenous fertilizers during cultivation. why?

Answer 1

Because Such Plants Are Leguminous Plants and they have a bacteria called rhizobium bacteria which converts the atmospheric nitrogen into liquefied nitrogen which can be used by plants. :)

Answer 2

It is to be seen here that every single plant is of different type. The case where nitrogen fertilizers are used externally during cultivation is for the non-leguminous plants. The plants which have been mentioned in the question are Leguminous Plants.

The thing with these plants is that they naturally have a bacteria named rhizobium whose work is to use the oxygen directly from the environment. This simply eliminates the need for external nitrogen fertilizers.