Explanation:

No-till farming (also called zero tillage or direct drilling) is a way of growing crops or pasture from year to year without disturbing the soil through tillage. No-till is an agricultural technique which increases the amount of water that infiltrates into the soil and increases organic matter retention and cycling of nutrients in the soil. Therefore statement 1 is correct.

Gypsum helps in dissolution of the salt clay pan found in soils that hinder the percolation of water. This increases the efficiency of irrigation as less water is needed to irrigate the same soil. Statement 2 is correct.

Allowing crop residue to remain in the field ‎reduces evaporation of farm soil water. So, statement 3 is also correct.