CSAT Solved Papers/ 2021/Q12
2021 CSAT — Q12
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:
-
Cover crops
-
Fertigation
-
Hydroponics
-
Mixed farming
-
Polyculture
-
Vertical farming
Which of the above farming practices can be compatible with agroecology, as implied by the passage?
Thinking pathway
Locate. This asks for the best-supported inference — with a “which items are compatible” stem, first extract the passage’s explicit criteria, then test each listed practice against them. The passage defines agroecology by three things: (i) “mimic the biodiversity levels and functioning of natural ecosystems”; (ii) close nutrient loops by “returning all nutrients… back to the soil such as through… farmyard manure”; (iii) use “natural processes to control pests and build soil fertility… through intercropping,” integrating “trees with livestock and crops.”
Test (scope-fit, item by item).
- Cover crops (1) — build soil, mimic natural ground cover, support the nutrient loop. Compatible.
- Mixed farming (4) — integrates livestock and crops; named almost verbatim. Compatible.
- Polyculture (5) — biodiversity-mimicking, the intercropping principle. Compatible.
- Fertigation (2) — delivering (typically chemical) fertilizer through irrigation runs against the closed-loop, farmyard-manure model. Not compatible.
- Hydroponics (3) — soil-less cultivation, antithetical to a soil-based nutrient loop. Not compatible.
- Vertical farming (6) — industrial, largely soil-less and monoculture-style; not a biodiversity mimic. Not compatible.
Eliminate by anatomy. (b)/(c)/(d) each admit at least one practice that violates the passage’s soil-based, biodiversity-mimicking definition (fertigation, hydroponics or vertical farming) — a claim the passage’s criteria never support: a real farming term that simply fails the passage’s stated criteria. Key: (a).
Evidence in the text
“Agroecosystems should mimic the biodiversity levels and functioning of natural ecosystems… closing nutrient loops… returning all nutrients that come out of the soil back to the soil such as through application of farmyard manure… harnesses natural processes to control pests and build soil fertility i.e., through intercropping… integrating trees with livestock and crops.” — the passage’s tests are biodiversity-mimicry, soil-based closed nutrient loops, and intercropping/integration. Cover crops (1), mixed farming (4) and polyculture (5) satisfy all three; fertigation (2, chemical-input irrigation), hydroponics (3, soil-less) and vertical farming (6, industrial/soil-less) violate the soil-based, biodiversity-mimicking criteria → (a).
Worked rationale
Agroecology, per the passage, mimics natural biodiversity, closes nutrient loops in the soil (farmyard manure), and works through intercropping and integrating trees/livestock/crops.
- 1 Cover crops, 4 Mixed farming, 5 Polyculture all match these principles. Compatible.
- 2 Fertigation (chemical-input irrigation), 3 Hydroponics (soil-less), 6 Vertical farming (industrial/soil-less) each violate the soil-based, biodiversity-mimicking model. Not compatible.
Answer: (a) 1, 4 and 5 only.
Why the other options miss
- B fails the passage’s criteria: keeps the valid 4 and 5 but adds fertigation and hydroponics, both at odds with the soil-based closed-loop definition.
- C fails the passage’s criteria: piles in fertigation, hydroponics and vertical farming — three practices that the passage’s criteria exclude.
- D fails the passage’s criteria: pairs the valid mixed farming with vertical farming, which is not a biodiversity mimic, and drops the valid cover crops and polyculture.
Specialist insight
This is a definition-matching item disguised as general-knowledge: a student who farms or has read about hydroponics/vertical farming as “modern and good” is tempted to include them. But “compatible with agroecology as implied by the passage” forces every practice through the passage’s own three tests — biodiversity mimicry, soil-based closed nutrient loops, intercropping/integration. Hydroponics and vertical farming are soil-less; fertigation is input-driven; all three fail. The ones that pass (cover crops, mixed farming, polyculture) are the diversity-and-soil practices. Read the passage’s criteria first; judge the list against them, not against what is fashionable.
Hydroponics, fertigation and vertical farming are real and modern but soil-less / input-driven — they fail the passage's soil-based biodiversity-mimic test, leaving 1, 4, 5 → (a).