Question

Soil can not store more nitrogen than it can hold. Hence soil is said to be in a state of unsaturation.
a.) True
b.) False

Answer 1

When a solute is dissolved in a solvent and more solute can not get dissolved, then the solvent is in state of saturation and if more solute can get dissolved in solvent, then it is in state of unsaturation.

Complete answer:
First, let us understand what saturation and unsaturation are.
The saturation means when some solute gets completely dissolved in a solvent to the extent that the solvent can not more dissolve it. This state is when the solvent is completely saturated.
The unsaturation means when we dissolve solute in solvent but solvent has capacity to dissolve more solute. At that time, the solvent is in a state of unsaturation.
In question, we have that the soil can not store more nitrogen than it can hold. So, the soil is in a state of saturation and not unsaturated.

Thus, the statement is false.

Note:
Nitrogen is an important nutrient for plant growth. Thus, it is given in the form of fertilizers to the plant. The soil stores some amount of nitrogen and the plant takes nitrogen from the soil. Some plants need more nitrogen than others. Even different soils have different capacity for holding nitrogen. The nitrogen levels are low in calcareous and gypsiferous soils because of high volatilization of nitrogen in the form of ammonia gas. The NPK fertilizers are supplied to provide nitrogen to the soil.