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 code given below:

1. Statement 1 is correct. Reduced or zero tillage involves minimizing soil disturbance. This practice helps retain soil moisture by reducing evaporation from the soil surface and improving water infiltration, thus contributing to water conservation. 2. Statement 2 is incorrect. Applying gypsum (calcium sulfate) is primarily done to improve soil structure, particularly in sodic soils, by replacing sodium with calcium. While improved soil structure can enhance water infiltration, gypsum application itself is not a direct water conservation technique aimed at reducing water use before irrigation. In some cases, improving infiltration might lead to needing more water initially to wet the profile, although better structure aids long-term water management. 3. Statement 3 is correct. Allowing crop residue to remain in the field (mulching) acts as a protective layer on the soil surface. This reduces water evaporation, suppresses weed growth (which competes for water), and improves soil moisture retention, thereby significantly helping in water conservation in agriculture. 4. Therefore, practices 1 and 3 directly help in water conservation.