With reference to agricultural soils, consider the following statements:
- 1.A high content of organic matter in soil drastically reduces its water holding capacity.
- 2.Soil does not play any role in the sulphur cycle.
- 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?
Answer & explanation
Answer: (b) 3 only
Only statement 3 is correct: repeated irrigation can leave salts in the soil and make farmland saline. Organic matter (humus) helps soil hold water, and soil is where sulphur is stored and converted into a form plants can use.
- ✗ 1. Humus, the dark organic matter of soil, is rich in nutrients and retains moisture. More organic matter raises water-holding capacity; it does not drastically reduce it.
- ✗ 2. Soil is a main site of the sulphur cycle. Sulphur added as elemental S must be oxidised to sulphate in the soil before plants can take it up.
- ✓ 3. NCERT notes that intensive irrigation in Punjab, Haryana and western Uttar Pradesh is increasing soil salinity, because irrigation water leaves dissolved salts behind as it evaporates.
Remember · Organic matter (humus) holds water; soil is a working part of the sulphur cycle; long-term irrigation can make soil saline.
📘 Read it in NCERT: Class 12 India: People and Economy, Ch 4 (practise this chapter) · Class 7 Exploring Society: India and Beyond (Part 2), Ch 1 (practise this chapter)
Sources
- NCERT Class 12 · India: People and Economy, Chapter 4 “Intensive irrigation in Punjab, Haryana and western Uttar Pradesh is increasing salinity in the soil”
- NCERT Class 7 · Exploring Society: India and Beyond (Part 2), Chapter 1 “Humus is the dark organic matter in soil that is formed by the decomposition of plant and animal matter. It is rich in nutrients and retains moisture in the soil.”
- Sulphur nutrition and the sulphur cycle (Rothamsted Research report hosted by FAO Soil Biodiversity portal) ↗ “Fertilisers in the form of elemental S need to be oxidised to sulphate in soils before they are available for plant uptake.”
Question and answer: UPSC's official GS Paper I (2018, Series A) — paper ↗ · answer key ↗. Explanation: Minimalist IAS, checked 30 Sept 2026 (how we verify). ·