Soils of India — Set 3

Correct Answer: C. Red Soil

• **Red soil** = formed by weathering of ancient crystalline and metamorphic rocks (granite and gneiss) in the Deccan plateau's eastern and southern parts. • **Granite and gneiss parent rock** — the ancient crystalline and metamorphic rocks that weather to form red soil. • 💡 Wrong-option analysis: Alluvial soil: deposited by rivers, not from rock weathering; Laterite soil: formed by leaching of nutrients in heavy rainfall; Black soil: formed from basaltic volcanic Deccan Trap rock.

Correct Answer: A. Chambal Basin

• **Chambal Basin** = famous for severe gully erosion and badland topography, where deep gullies/ravines make land unsuitable for cultivation. • **Badland topography (ravines)** — the characteristic landscape of the Chambal basin caused by gully erosion in clayey soils. • 💡 Wrong-option analysis: Ganga Basin: major agricultural plain, not primarily known for gully erosion; Krishna Basin: southern river, not associated with ravine formation; Brahmaputra Basin: flood plains of Assam, not gully erosion.

Correct Answer: D. Black Soil

• **Black soil** = has the highest water retention capacity due to its high clay content, swelling when wet and holding moisture for long periods. • **High clay content** — the structural reason for black soil's exceptional water retention, beneficial for rain-fed crops like cotton. • 💡 Wrong-option analysis: Alluvial soil: fertile and productive but not the highest water retention; Red soil: low clay content, low water retention; Laterite soil: porous due to iron oxides, relatively poor water retention.

Correct Answer: D. Phosphate

• **Phosphate** = arid soils of Rajasthan are rich in phosphate but deficient in nitrogen and lack humus. • **High soluble salt concentration** — the defining chemical feature of desert/arid soils that affects crop productivity. • 💡 Wrong-option analysis: Humus: absent/very low in desert soils; Magnesium: black soil is rich in Mg, not desert soils; Nitrogen: arid soils are actually deficient in nitrogen.

Correct Answer: B. Leaching

• **Leaching** = the primary process forming laterite soil, where percolating heavy rainwater removes dissolved silica and lime, leaving iron and aluminum oxides. • **Silica and lime removed** — the specific nutrients lost through leaching that explains laterite's poor fertility for regular crops. • 💡 Wrong-option analysis: Animal activity: helps in humus formation but doesn't create laterite; Frost action: relevant in mountain soil formation; Wind action: creates desert/arid soils.

Correct Answer: A. Jammu and Kashmir

• **Karewa soils in Jammu and Kashmir** = lacustrine glacial clay deposits of the Kashmir Valley, exceptionally fertile for saffron cultivation. • **Saffron (Zafran) cultivation** — the world-famous crop grown in Kashmir's Karewa deposits; also supports almond and walnut orchards. • 💡 Wrong-option analysis: Himachal Pradesh: known for apple orchards, not Karewa soil; Sikkim: known for organic farming, no Karewa; Arunachal Pradesh: forest/mountain soils, no Karewa deposits.

Correct Answer: B. Laterite Soil

• **Laterite soil on Eastern Ghats and Rajmahal hills** = found on high-level plateaus and summits, result of extreme tropical weathering. • **Nutrient-poor due to high leaching** — laterite soil on Eastern Ghats summits is very poor in nutrients despite being in high-rainfall zones. • 💡 Wrong-option analysis: Alluvial soil: found in river valleys/deltas, not hill summits; Desert soil: found in dry Rajasthan/NW India; Black soil: Deccan Trap volcanic region, not Eastern Ghats summits.

Correct Answer: D. Coastal and arid areas

• **Shelter Belts in coastal and arid areas** = rows of trees planted to reduce wind velocity and protect soil from wind erosion in Rajasthan deserts and coastal sandy areas. • **Stabilisation of sand dunes** — the key outcome of shelter belts in desert regions of Rajasthan. • 💡 Wrong-option analysis: Plateau regions: contour bunding/terrace farming is used; River deltas: flood management and embankments used; Mountainous areas: terrace farming and contour bunding used.

Correct Answer: B. High humus in lower valleys

• **High humus in lower valleys** = forest soil in lower valleys is fertile and loamy due to leaf litter accumulation; upper slopes are acidic and poor. • **Altitude-dependent variation** — forest soil properties change significantly with altitude: loamy/humus-rich in valleys, acidic/coarse on upper slopes. • 💡 Wrong-option analysis: High salt content: that is saline soil, not forest soil; Rich in calcium: alluvial/black soils have higher calcium; Yellowish color: describes hydrated form of red soil.

Correct Answer: A. Black Soil

• **Black soil in Maharashtra** = the Deccan Trap volcanic region's primary state, covered by black soil excellent for cotton cultivation. • **Cotton-based economy** — Maharashtra's textile industry depends heavily on the black soil that supports massive cotton cultivation. • 💡 Wrong-option analysis: Laterite soil: found in Kerala/Karnataka coastal areas; Alluvial soil: northern plains soil, not Maharashtra's Deccan; Red soil: found in eastern/southern Deccan, not Maharashtra primarily.