UPSC Prelims 2021 CSAT Paper II · Q12 of 79 Comprehension medium

Passage

At the heart of agroecology is the idea that agroecosystems should mimic the biodiversity levels and functioning of natural ecosystems. Such agricultural mimics, like their natural models, can be productive, pest-resistant, nutrient conserving, and resilient to shocks and stresses. In ecosystems there is no 'waste', nutrients are recycled indefinitely. Agroecology aims at closing nutrient loops, i.e., returning all nutrients that come out of the soil back to the soil such as through application of farmyard manure. It also harnesses natural processes to control pests and build soil fertility i.e., through intercropping. Agroecological practices include integrating trees with livestock and crops.

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 ?

  1. (a) 1, 4 and 5 only ✓ UPSC's answer
  2. (b) 2, 3, 4 and 5 only
  3. (c) 1, 2, 3 and 6 only
  4. (d) 4 and 6 only

Why the answer is (a)

• The passage defines agroecology as mimicking natural ecosystems, closing nutrient loops, and harnessing natural processes for pest control and soil fertility.

• Cover crops (1) are compatible because they protect soil, fix nitrogen, and mimic natural ground cover, aligning with nutrient conservation.

• Mixed farming (4) is explicitly supported by the passage's mention of 'integrating trees with livestock and crops,' which is the core of mixed farming.

• Polyculture (5) is compatible as it involves growing multiple crops together, similar to the 'intercropping' mentioned in the passage for pest control and biodiversity.

• Therefore, options 1, 4, and 5 are the practices that align with the principles of biodiversity, nutrient cycling, and natural process harnessing described in the text.

Why the other options are wrong

(b) 2, 3, 4 and 5 only
Fertigation (2) and Hydroponics (3) are excluded because they rely on external inputs and soil-less systems, respectively, rather than the natural nutrient cycling and soil-based biodiversity emphasized in the passage.
(c) 1, 2, 3 and 6 only
Fertigation (2), Hydroponics (3), and Vertical farming (6) are excluded as they represent high-input, technology-driven, or soil-less methods that do not mimic the natural ecosystem functioning and nutrient loops described.
(d) 4 and 6 only
This option is incorrect because it excludes Cover crops (1) and Polyculture (5), which are explicitly compatible with the passage's emphasis on intercropping and natural soil management.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2021, held on 10 October 2021. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

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