A farmer observes that his crop field has depleted nitrogen levels. He decides to grow a crop of leguminous plants like peas, followed by wheat in the next season. How does this practice organically restore soil fertility?

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A The pea plants directly absorb nitrogen gas from the air through their leaves and pump it into the soil.
B Rhizobium bacteria living in the root nodules of the pea plants fix atmospheric nitrogen into usable nitrates, enriching the soil.
C The deep roots of the pea plant physically pull nitrogen up from the core of the Earth to the topsoil.
D Viruses present in the soil break down decaying organic matter into pure nitrogen gas.

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Answer: B. Rhizobium bacteria living in the root nodules of the pea plants fix atmospheric nitrogen into usable nitrates, enriching the soil.

Plants need nitrogen to grow, but they cannot absorb pure nitrogen gas (N₂) straight from the atmosphere. Leguminous plants (like peas, beans, and pulses) share a symbiotic relationship with a specific bacterium called Rhizobium, which houses itself inside nodules on the plant's roots. These bacteria take nitrogen gas from the air spaces in the soil and chemically convert it into usable compounds like nitrates. When the crop is harvested, these nutrients stay behind, enriching the soil naturally

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A farmer observes that his crop field has depleted nitrogen levels. He decides to grow a crop of leguminous plants like peas, followed by wheat in the next season. How does this practice organically restore soil fertility?

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