With reference to agricultural soils, consider the following statements :
- A high content of organic matter in soil drastically reduces its water holding capacity.
- Soil does not play any role in the sulphur cycle.
- Irrigation over a period of time can contribute to the salinization of some agricultural lands.
Which of the statements given above is/are correct ?
1 and 2 only
3 only
1 and 3 only
1, 2 and 3
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC IAS – 2018
1. **A high content of organic matter in soil drastically reduces its water holding capacity:** This statement is incorrect. Organic matter is like a sponge; it significantly *increases* the soil’s ability to absorb and retain water. Soils with high organic matter content hold much more water than soils with low organic matter.
2. **Soil does not play any role in the sulphur cycle:** This statement is incorrect. Soil plays a vital role in the sulphur cycle. It is a major reservoir for sulphur, primarily in organic form. Microorganisms in the soil are essential for the transformation of sulphur compounds (e.g., decomposition of organic matter releasing sulphate, oxidation and reduction reactions of sulphur compounds). Plant uptake of sulphate from the soil is also a key part of the cycle.
3. **Irrigation over a period of time can contribute to the salinization of some agricultural lands:** This statement is correct. Irrigation water, especially in arid and semi-arid regions, contains dissolved salts. When water is applied to fields, plants use some water, and much of it evaporates from the soil surface. The dissolved salts, however, are left behind. Without adequate drainage, these salts accumulate in the topsoil over time, leading to salinization, which reduces soil fertility and plant growth.