Which of the following practices can help in water conservation in agriculture? 1. Reduced or zero tillage of the land 2. Applying gypsum before irrigating the field 3. Allowing crop residue to remain in the field. Select the correct answer using the codes given below:

The correct answer is C (1 and 3 only). Both reduced or zero tillage and retaining crop residue cut evaporation and keep moisture in the root zone.

• Statement 1 is correct. Zero or reduced tillage leaves the soil structure and surface cover undisturbed, which lowers evaporative loss and preserves soil moisture. Conservation agriculture rests on this idea.
• Statement 2 is wrong. Gypsum is a chemical amendment for reclaiming sodic (alkaline) soils. It replaces excess sodium with calcium and improves infiltration and structure there. It is a reclamation measure, not a general water-saving practice for irrigated fields.
• Statement 3 is correct. Crop residue works as surface mulch. It reduces evaporation, moderates soil temperature and slows runoff, so more water stays available to the crop.

Core concept: soil moisture conservation through mulching and minimum soil disturbance. This links to the Mains theme of sustainable agriculture, water-use efficiency and the environmental cost of stubble burning, since burning removes the residue that could conserve moisture.

Trap: candidates see gypsum's role in improving soil water infiltration and assume it saves water in general. It helps only in sodic soils and is not a universal conservation practice.