With reference to agricultural soils, consider the following statements: 1. A high content of organic matter in soil drastically reduces its water holding capacity. 2. Soil does not play any role in the sulphur cycle. 3. Irrigation over a period of time can contribute to the salinization of some agricultural lands. Which of the statements given above is/are correct?

Let's evaluate each statement regarding agricultural soils:

1. A high content of organic matter in soil drastically reduces its water holding capacity. This statement is incorrect. Organic matter significantly increases the soil's water holding capacity. Organic matter acts like a sponge, absorbing and holding water, which is crucial for plant growth, especially in sandy soils. It also improves soil structure, leading to better infiltration and reduced runoff.

2. Soil does not play any role in the sulphur cycle. This statement is incorrect. Soil plays a vital and complex role in the sulphur cycle. Sulphur exists in various forms in the soil (organic sulphur, sulphates, sulfides), and numerous microbial processes (like mineralization, oxidation, reduction) occur in the soil, transforming sulphur compounds and making them available or unavailable to plants. Soil is a major reservoir and site of active sulphur cycling.

3. Irrigation over a period of time can contribute to the salinization of some agricultural lands. This statement is correct. Irrigation water, even if it appears fresh, contains dissolved salts. When this water is applied to fields, a significant portion evaporates from the soil surface and transpires through plants, leaving the salts behind in the topsoil. Over time, especially in arid and semi-arid regions with poor drainage, this continuous accumulation of salts leads to soil salinization, making the land less productive or even barren for agriculture.

Therefore, only statement 3 is correct.