Which among the following crops helps in restoring soil fertility by fixing nitrogen from the air?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Pulses
Note: The given answer is as per the official NTA Answer Key. However, the question has two possible answers, i.e. both Option (2) and Option (4), as explained below.
Pulses are leguminous crops. Their roots carry nodules in which Rhizobium bacteria take nitrogen from the air and turn it into compounds the plant can use. Part of this nitrogen stays in the soil with the roots and leaves after harvest, so legumes restore soil fertility and are grown in rotation with other crops.
Option (2) Pulses — the whole group of leguminous food crops, such as gram, urad, moong, masur and peas; this is the answer given by NTA.
Option (4) Rajma — rajma (kidney bean) is itself a pulse, a legume with root nodules, so it also fixes nitrogen from the air.
Millets and sugarcane are not legumes; they have no such nodules and take their nitrogen from the soil.
Tip for students: When a question has two possible answers, mark the one you worked out yourself. If NTA’s answer key gives a different answer, challenge it when NTA opens the window for challenges.