Correct Option (C)
Statements 1 and 3 are correct. These practices contribute to water conservation in agriculture by enhancing soil moisture retention and reducing evaporative losses.
- Reduced or zero tillage minimizes soil disturbance, which helps maintain soil structure and organic matter. This improves the soil's capacity to absorb and retain water, reducing runoff and evaporation.
- Allowing crop residue to remain in the field, also known as mulching, covers the soil surface. This cover reduces direct exposure to sunlight and wind, thereby decreasing water evaporation from the soil. It also helps in moderating soil temperature and improving soil organic matter over time.
Incorrect Options:
- Statement 2 is incorrect. Applying gypsum (calcium sulfate) is primarily used to improve soil structure, particularly in sodic soils, by replacing sodium with calcium. While improved soil structure can indirectly enhance water infiltration and drainage, gypsum itself does not directly conserve water. Its primary role is soil amendment for specific soil conditions, not water retention. Excessive application could potentially lead to nutrient leaching.