UPSC Prelims 2017 · Question 21 of 99

UPSC Prelims 2017 question on Water Conservation Agriculture

Which of the following statements 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:

  1. 1 and 2 only
  2. 3 only
  3. 1 and 3 only
  4. 1, 2 and 3
Show answer

Answer: D. 1, 2 and 3

Verdict

The answer is 1, 2 and 3. Zero tillage, gypsum application and retaining crop residue all help conserve water in agriculture.

Analysis

Statement 1 is CORRECT. No till or zero tillage grows crops without disturbing the soil, which increases infiltration of water into the soil and improves organic matter retention and nutrient cycling. Statement 2 is CORRECT. Gypsum improves soil structure and drainage, preventing waterlogging and thereby raising water use efficiency, and it is particularly useful on sodic soils where poor structure blocks infiltration. Statement 3 is CORRECT. Crop residue left on the surface acts as a mulch, reducing evaporation and runoff and holding moisture in the root zone.

Source

Food and Agriculture Organization material on conservation agriculture and agronomic sources on micronutrients.

How to crack it

All three practices work through the same two levers, increasing how much rain enters the soil and reducing how much leaves it. Ask of each option whether it raises infiltration or lowers evaporation and runoff, and every one of them qualifies. Conservation agriculture is built on exactly this triad of minimum tillage, permanent soil cover and crop rotation, so learning the package answers questions about any of its components.

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