Static Quiz 09 September 2026 (Geography)

The correct descending order is Alluvial, Red and Yellow, Black, then Laterite. Alluvial soil covers approximately 43% of India's total land area, the most widespread type, found across the Indo-Gangetic Plain, river deltas, and coastal plains, and the most fertile and agriculturally productive soil, while Red and Yellow soil covers roughly 18-20%, found across peninsular India in Tamil Nadu, Andhra Pradesh, Chhattisgarh, Odisha, and Jharkhand, its red colour coming from iron oxide content. Black, or Regur, soil covers roughly 15% in the Deccan Trap region across Maharashtra, Madhya Pradesh, Gujarat, and Andhra Pradesh, famous for cotton cultivation and high moisture retention, while Laterite soil covers only about 3-4%, found in high-rainfall areas of Kerala, Karnataka, Meghalaya, and Odisha where intense leaching removes nutrients.

Black soil, or Regur, is renowned for its property of self-ploughing, since in summer the soil dries out and develops wide, deep cracks that allow air and water to penetrate the lower layers, while it swells and becomes extremely sticky and difficult to work when wet, a moisture behaviour that makes it ideal for cotton, which requires moisture during growth and dry conditions at harvest. Option (a) is wrong since black soil is actually formed from the weathering of Deccan Trap basaltic lava rocks of volcanic origin, not crystalline or metamorphic rocks, and is deficient in nitrogen and organic matter rather than rich, option (c) is incorrect since black soil is found in the Deccan Plateau region rather than the eastern Himalayan foothills or Brahmaputra valley, and option (d) misstates its composition, since black soil is actually rich in iron, lime, calcium, potassium, and magnesium but deficient in nitrogen, phosphorus, and organic matter.

Statement 1 is correct. Laterite soil forms through laterisation, where intense leaching under high temperature and heavy rainfall removes soluble nutrients and silica, leaving behind iron and aluminium oxides whose high iron content gives it the characteristic reddish-brown colour, found in Kerala, Karnataka, parts of Odisha, and Meghalaya. Laterite soil is actually highly infertile, since the leaching process removes most plant nutrients, and it is not suitable for rice, wheat, or sugarcane without heavy fertiliser application, with crops like cashew, tea, coffee, and rubber, which can tolerate acidic, nutrient-poor conditions, more commonly grown where cultivation occurs on laterite soils.

Khadar, or new alluvial soil, renewed annually by river flooding and high in nitrogen, phosphorus, and organic matter, is ideal for rice, wheat, sugarcane, and pulses in the Indo-Gangetic Plain and river deltas, while Black, or Regur, soil, with high moisture retention and self-ploughing properties, is the classic soil for cotton, giving the Deccan region its name as India's "Cotton Belt," while also supporting jowar, wheat, and linseed. Red soil, deficient in nitrogen and phosphorus but well-drained, supports groundnut, millets, pulses, and oilseeds across the Deccan Plateau and peninsular India, and Arid and desert soil, with high sand content, very low moisture retention, and low organic matter, only supports drought-resistant crops like bajra, guar, and some coarse millets, though irrigation transforms productivity dramatically.

Both A and R are correct, and R directly explains A. Alluvial soils of the Indo-Gangetic Plain are globally recognised for their high inherent fertility, yet India's Green Revolution era and subsequent decades of intensive cropping have required increasing fertiliser inputs to maintain yields, indicating nutrient depletion. Continuous multi-crop cultivation, excessive irrigation leading to waterlogging and soil salinity, particularly in Punjab and Haryana, and reduced natural flooding that once replenished nutrients together explain why soils once naturally fertile now require supplementation, making R the direct causal explanation for the paradox described in A, high-potential soils requiring intensive external inputs.