Question

Nitrogen is an essential nutrient for plant growth. But farmers
who cultivate pulse crops like green gram, bengal gram,
black gram, etc. do not apply nitrogenous fertilizers during
cultivation. Why?


NCERT Class VIII
Science - Exemplar Problems

Chapter 1. Nuitrion in Plants

Answer 1

Nitrogen is an essential nutrient for plant growth. But farmers who cultivate pulse crops like green gram, bengal gram,black gram, etc. do not apply nitrogenous fertilizers during cultivation because of following reason:
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1. Leguminous plants like green gram, bengal gram,black gram contain nitrogen fixing " RHIZOBIUM " bacteria which convert nitrogen gas of air into nitrogen compounds which can be used by plants for their compounds
2. The nitrogen fixing Rhizohium bacteria live in the root nodules of leguminous plants.
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Answer 2

Answer: Roots of pulses like (leguminous plants)have a symbiotic association with a bacterium called rhizobium which fixes nitrogen. Hence , farmers need not to use nitrogenous fertilizer

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