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Prelims 2018 · Q82 · Crops & farming practices

With reference to agricultural soils, consider the following statements :

  1. 1.A high content of organic matter in soil drastically reduces its water holding capacity.
  2. 2.Soil does not play any role in the sulphur cycle.
  3. 3.Irrigation over a period of time can contribute to the salinization of some agricultural lands.

Which of the statements given above is/are correct ?

Show answer

Answer: B. Statement 1 is wrong: organic matter increases, not reduces, the soil's water-holding capacity. Statement 2 is wrong: soil is a major store of sulphur and soil microbes drive the sulphur cycle. Statement 3 is correct: irrigation without proper drainage leaves salts behind, causing salinisation. So only 3.

Watch for: Extreme words like 'drastically' and 'does not play any role' signal false statements.

Why the other options are wrong
  • A. Wrong because organic matter increases water-holding capacity and soil is part of the sulphur cycle.
  • C. Wrong because organic matter increases, not decreases, water-holding capacity.
  • D. Wrong because statements 1 and 2 are false.

Source to check: NCERT Class 11 'Fundamentals of Physical Geography', Chapter 6 'Geomorphic Processes' (soil formation); NCERT Class 10 'Contemporary India II', Chapter 1 (soil degradation)

Answer from the official UPSC key. Written and fact-checked by AI against the official key. Spotted a mistake? Report it.