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:

Correct Option: 1 and 3 only

Reduced or zero tillage (Statement 1) helps preserve soil moisture by minimizing soil disturbance and evaporation. Allowing crop residue to remain in the field (Statement 3) acts as a mulch, reducing soil moisture loss through evaporation and improving water infiltration. Gypsum application is typically used for reclaiming sodic/alkaline soils and improving soil structure, but it is not primarily a water conservation practice in the context of the standard agronomic techniques listed.