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 :
- (a) 1 and 2 only
- (b) 3 only
- (c) 1 and 3 only ✓ UPSC's answer
- (d) 1, 2 and 3
Why the answer is (c)
• Reduced or zero tillage (1) leaves soil structure intact, cutting evaporation and improving infiltration and moisture retention.
• Crop residue left as mulch (3) shades the soil, reduces evaporation and run-off, and adds organic matter that holds water.
• Applying gypsum (2) reclaims sodic (alkaline) soils by replacing sodium with calcium; it improves soil structure but is a soil-reclamation, not a water-conservation, practice per the key.
• Hence 1 and 3 only, option (c).
Why the other options are wrong
- (a) 1 and 2 only
- Gypsum is for soil reclamation, not water conservation; residue mulch is.
- (b) 3 only
- Zero tillage also conserves water.
- (d) 1, 2 and 3
- Gypsum application is not a water-conservation practice.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2017, held on 18 June 2017. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.