Question

The leguminous plants are important in agriculture because:
A. They are disease resistant.
B. They require very little irrigation.
C. They help in the nitrogen economy of nature.
D. Crops of legumes can be produced in a year.

Answer 1

Hint: The leguminous plants are those plants that grow in nitrogen-rich soil and trap nitrogen inside its fruit with the help of some nitrogen-fixing bacteria.
Some examples of leguminous plants are alfalfa, clover, beans, soybeans, peanuts, etc.

Complete answer: Leguminous species are very important as part of a rotational production of a cereal crop.
It helps to fix nitrogen from the atmosphere to the soil and plant through symbiotic associations with root dwelling bacteria.
Free-living bacteria such as Rhizobium fix atmospheric nitrogen and add it to the soil to maintain the nitrogen pool of the environment. This process is called biological nitrogen fixation. It is a natural process and highly beneficial in the field of agriculture.
Other nitrogen-fixing bacteria such as Azotobacter form associations in the form of nodules with the roots of leguminous plants and help in nitrogen trapping.

Thus, the correct answer is option C. They help in the nitrogen economy of nature.

Note: Animals cannot intake nitrogen from atmosphere directly.
Leguminous plants trap nitrogen from the atmosphere and trap it inside it and by the intake of those plants, animals get nitrogen as a part of nutrition.