UPSC Prelims 2023 CSAT Paper II · Q42 of 77 Comprehension medium

Passage

Passage – 2 A global analysis of nitrogen use efficiency — a measure of the amount of nitrogen a plant takes in to grow versus what is left behind as pollution — says that using too much fertilizers will lead to increased pollution of waterways and the air. Currently, the global average for nitrogen use efficiency is approximately 0·4, meaning 40 per cent of the total nitrogen added to cropland goes into the harvested crop while 60 per cent is lost to the environment, says a study. More than half of the world's population is nourished by food grown with fertilizers containing synthetic nitrogen, which is needed to produce high crop yields. Plants take the nitrogen they need to grow, and the excess is left in the ground, water and air. This results in significant emissions of nitrous oxide, a potent greenhouse and ozone depleting gas, and other forms of nitrogen pollution, including eutrophication of lakes and rivers and contamination of river water.

Which one of the following statements best reflects the most logical, rational and crucial message implied by the passage ?

  1. (a) An enhanced efficiency of use of nitrogen is imperative for both food production and environment. ✓ UPSC's answer
  2. (b) Production of synthetic nitrogen fertilizers cannot be stopped as it will adversely affect global food security.
  3. (c) Alternatives to crops that require excess of nitrogen should be identified and cultivated.
  4. (d) Conventional agriculture using synthetic fertilizers should be replaced with agroforestry, agroecosystems and organic farming.

Why the answer is (a)

• The passage highlights that the global average nitrogen use efficiency is only 0.4, meaning 60% of added nitrogen is lost to the environment as pollution.

• It explicitly states that using too much fertilizer leads to increased pollution of waterways and air, including nitrous oxide emissions and eutrophication.

• Simultaneously, the text notes that more than half the world's population relies on food grown with synthetic nitrogen for high yields, indicating that nitrogen is essential for food security.

• Therefore, the core message is that we must improve how efficiently nitrogen is used to maintain food production while minimizing environmental damage.

• Option (a) captures this dual necessity by stating that enhanced efficiency is imperative for both food production and the environment.

Why the other options are wrong

(b) Production of synthetic nitrogen fertilizers cannot be stopped as it will adversely…
The passage does not argue that production cannot be stopped, but rather that the *efficiency* of use must be improved to reduce pollution while maintaining yields.
(c) Alternatives to crops that require excess of nitrogen should be identified and cultivated.
The passage does not suggest switching to different crops, but rather improving the efficiency of nitrogen use in current agricultural practices.
(d) Conventional agriculture using synthetic fertilizers should be replaced with…
The passage does not advocate for replacing conventional agriculture with agroforestry or organic farming, but for optimizing nitrogen use efficiency within the context of synthetic fertilizer reliance.

Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2023, held on 28 May 2023. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.

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