UPSC CSE Prelims
Question 79
Which of the following practices can help in water conservation in agriculture ?
- Reduced or zero tillage of the land
- Applying gypsum before irrigating the field
- Allowing crop residue to remain in the field
Select the correct answer using the code given below :
View correct answer and explanation
Correct answer: C
Correct Option: C
Explanation: Reduced tillage and retaining plant residues preserve soil moisture by limiting evaporation, runoff and disturbance. Applying gypsum is chiefly a measure for ameliorating sodic soils, not a general water-saving practice.
Statement/Pair-wise Analysis:
Statement/Item 1: Correct - Zero or minimum tillage helps retain soil structure and moisture.
Statement/Item 2: Incorrect - Gypsum is a soil amendment for sodicity and structure; it is not routinely classed as a water-conservation technique.
Statement/Item 3: Correct - Residue mulch shades soil and cuts moisture loss through evaporation.
Option-wise Analysis:
A: Incorrect - includes incorrect statement/item 2; omits correct statement/item 3.
B: Incorrect - omits correct statement/item 1.
C: Correct - includes all and only the true statements/items.
D: Incorrect - includes incorrect statement/item 2.
Review Note: Gypsum can improve infiltration on certain sodic soils, but that specific benefit does not make it a generally applicable water-conservation method in the 2017 key.