Question

If the wheat field is inoculated with Rhizobium, then
A. Soil will become nitrogen-rich
B. No effect on soil nitrogen
C. Soil will be depleted of nitrogen
D. Soil will become rich in calcium

Answer 1

Hint: Rhizobium is present in the root nodules of plants. They are present in the symbiotic relationship with the plants and take their food from plants and help in absorbing the mineral from the soil for plant growth.

Complete answer: Wheat is the crop whose development is completely based on the nitrogen presence.
1. They grow in the field which is rich in nitrogen and completely utilizes all the nitrogen from the field of that area.
2. So after completion of the wheat crop, we should have completely the nitrogen in the field for further use.
3. For that purpose, we should add Rhizobium bacteria in the field. It is a soil friendly bacteria and also increases plant growth.
4. As Rhizobium is a Symbiont organism it lives in a symbiotic relationship with the plants. It is present in the root nodules and absorbs minerals from the soil for plant growth.
5. Also, the important function of Rhizobium is nitrogen fixation. It converts the atmospheric nitrogen into the form which is suitable for the plant and is easily absorbed by the plants.
6. In this way, the nitrogen depleted due to the wheat crop is again increased in the soil and again soil will become rich in all minerals and fertile.
7. So from the above explanation, we can say that by inoculation of Rhizobium in the field soil will become rich in nitrogen.

Option A is correct.

Note: Farmers grow different crops which naturally have Rhizobium in its root nodules and by the means of crop cycle they maintain the mineral level constant in the soil.