UPSC Prelims 2021 · CSAT
Question 12: Reading Comprehension
Consider the following :
- 1.Cover crops
- 2.Fertigation
- 3.Hydroponics
- 4.Mixed farming
- 5.Polyculture
- 6.Vertical farming
Which of the above farming practices can be compatible with agroecology, as implied by the passage ?
AnswerUPSC’s answer is (a).
Agroecology copies natural ecosystems: diverse, recycling nutrients to the soil, and using natural processes for pests and fertility. Cover crops (1) protect and feed the soil naturally. Mixed farming (4) joins crops, livestock and trees and returns manure to the soil. Polyculture (5) is diversity of crops, like intercropping. Fertigation (2) feeds crops with fertiliser through irrigation, while hydroponics (3) and vertical farming (6) grow plants without soil, so they cannot close nutrient loops through the soil or mimic natural diversity. Remember: practices that return nutrients to soil and raise diversity fit agroecology; soilless or input-fed systems do not.
- 1. Cover crops build soil fertility through natural processes.
- 2. Fertigation supplies fertiliser through irrigation water rather than recycling nutrients to the soil.
- 3. Hydroponics grows plants without soil, so there is no nutrient loop through the soil.
- 4. Mixed farming combines crops, livestock and often trees, and returns manure to the soil.
- 5. Polyculture raises crop diversity, as intercropping does.
- 6. Vertical farming is soilless and input-fed, so it does not mimic natural ecosystems.
How you could have got this
- If you were sure statement 1 is correct, (b) and (d) go: each of them leaves 1 out.
What you needed to know: Cover crops build soil fertility through natural processes.
- Then, if you were sure statement 2 is not correct, (c) goes: it includes 2.
What you needed to know: Fertigation supplies fertiliser through irrigation water rather than recycling nutrients to the soil.
Only (a) is left. You didn’t need statements 3, 4, 5 or 6.
Which options go is worked out from UPSC’s key and the options, not by a model.
Why each option is right or wrong
- (a) Right: cover crops, mixed farming and polyculture build soil fertility and diversity naturally.
- (b) Includes fertigation and hydroponics, which rely on fed inputs or no soil, and leaves out cover crops.
- (c) Fertigation, hydroponics and vertical farming are input-fed or soilless, so they do not recycle nutrients through soil.
- (d) Vertical farming is soilless and returns no nutrients to soil; this also leaves out cover crops and polyculture.
Answer: UPSC’s key. Explanation: written by UPSC Grade, not by UPSC.
Source: UPSC, Civil Services (Preliminary) Examination 2021, General Studies Paper II (CSAT), Series A. The paper on upsc.gov.in.