UPSC Prelims 2017 Q71: Environment & Ecology – Sustainable Agriculture & Forestry
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
- (d) 1, 2 and 3
Answer: (c) 1 and 3 only
Explanation
Water conservation in agriculture
| Practice | Helps conserve water? | Reason |
|---|---|---|
| 1. Reduced or zero tillage of the land | Yes | Undisturbed soil loses less moisture by evaporation |
| 2. Applying gypsum before irrigating the field | No (official key) | Gypsum is a soil amendment used to reclaim sodic (alkali) soils |
| 3. Allowing crop residue to remain in the field | Yes | Residue acts as mulch; it shades the soil and cuts evaporation |
Practices 1 and 3 are parts of conservation agriculture.
Note on the key:
| View | Answer |
|---|---|
| UPSC official key | (c) 1 and 3 only |
| Some experts | (d), since gypsum improves water infiltration in sodic soils |
On the exam, go with the official key.
Answer: (c) 1 and 3 only.
Why each option is right or wrong
- (a) Incorrect. Statement 3 is left out, and gypsum is not counted by the official key.
- (b) Incorrect. Reduced or zero tillage also helps in water conservation.
- (c) CORRECT. Zero tillage and leaving crop residue in the field both save soil moisture.
- (d) Incorrect. The official key leaves out applying gypsum, a soil reclamation step.
Key point
Conservation agriculture = minimum tillage + crop residue cover + crop rotation; gypsum reclaims sodic soils (official key: 1 and 3 only).
Remember
Zero tillage + crop residue = water saved.
Common mistakes
- Thinking ploughing helps the soil hold water; it exposes moisture to evaporation.
- Treating gypsum as a water-saving input; its main use is reclaiming sodic soils.
- Forgetting that crop residue left in the field also stops stubble burning.
Exam tip
Cover the soil and disturb it less: both keep moisture in.
Sources
- Indian Council of Agricultural Research — Conservation Agriculture
- Food and Agriculture Organization — Conservation Agriculture principles