Soils of India — Set 5

Correct Answer: D. Black Soil

• **Black soil = Self-mulching soil** = shrinks and cracks when dry, the surface falls into cracks causing natural layer mixing, maintaining moisture in lower levels. • **Shrink-crack-mix cycle** — the natural self-mulching mechanism of black soil that benefits rain-fed crops. • 💡 Wrong-option analysis: Laterite soil: becomes hard when dry, no self-mulching; Peaty soil: waterlogged organic soil, no cracking; Alluvial soil: fertile but no self-mulching property.

Correct Answer: D. Coastal Odisha and Tamil Nadu

• **Coastal Odisha and Tamil Nadu** = the humid coastal zones where peaty and marshy soils form from accumulated organic matter. • **Humid coastal accumulation** — the process of organic matter build-up in waterlogged coastal areas creating peaty soil. • 💡 Wrong-option analysis: Western Rajasthan: arid desert soil; Central MP: black/red soil zone; Northern Punjab: alluvial Indo-Gangetic soil.

Correct Answer: B. Soil Erosion

• **Soil Erosion** = the displacement of the upper soil layer by natural agents (wind and water), accelerated by deforestation and poor land management. • **Loss of agricultural productivity** — the primary consequence of soil erosion that threatens India's food security. • 💡 Wrong-option analysis: Soil Fertilization: adding nutrients to soil, opposite of erosion's effect; Soil Mulching: covering soil to conserve moisture; Soil Salination: salt accumulation, different from mechanical erosion.

Correct Answer: B. Pebbly and porous soil

• **Pebbly and porous soil in Bhabar** = the Bhabar belt at Himalayan foothills where rivers deposit coarse pebbles; small streams disappear underground. • **Streams disappear underground** — the characteristic phenomenon of Bhabar where highly porous soil absorbs streams completely. • 💡 Wrong-option analysis: Marshy soil: that is the Tarai belt just south of Bhabar; Fine clayey soil: found in Tarai/floodplains; Rich black soil: Deccan Trap region, not Himalayan foothills.

Correct Answer: D. Maharashtra

• **Maharashtra** = has India's largest concentration of black soil, followed by Gujarat and MP, supporting the state's cotton-based economy. • **Cotton-based economy** — Maharashtra's black soil supports massive cotton cultivation central to its textile/industrial economy. • 💡 Wrong-option analysis: Karnataka: has black soil but smaller area than Maharashtra; Gujarat: second largest black soil area; Madhya Pradesh: third, both behind Maharashtra.

Correct Answer: B. Pulses and Millets

• **Pulses and Millets** = the primary crops in red soils of the Deccan plateau; also tobacco and groundnut due to the dry conditions. • **Adapted to dry eastern Deccan conditions** — millets and pulses are drought-tolerant crops suited to red soil's low moisture retention. • 💡 Wrong-option analysis: Cotton: needs black soil's moisture retention, not red soil; Wheat: needs alluvial/black soil and irrigation; Sugarcane: needs alluvial/black soil with high moisture.

Correct Answer: B. Laterite Soil

• **Laterite soil** = most commonly used for brick-making because it hardens significantly upon drying, cut into blocks used as durable construction material. • **Southern India construction tradition** — the practice of using laterite blocks for buildings is widespread in Kerala, Karnataka, and Goa. • 💡 Wrong-option analysis: Red soil: doesn't harden like laterite when dry; Alluvial soil: soft and fertile, not used for bricks; Desert soil: sandy and crumbly, cannot be cut into bricks.

Correct Answer: D. Mixed Red and Black Soil

• **Mixed Red and Black Soil in Bundelkhand** = the UP/MP border transition zone showing characteristics of both the peninsular plateau and the plains. • **Transition zone characteristics** — Bundelkhand's mixed soil reflects the geographic boundary between the Deccan plateau and the Gangetic plains. • 💡 Wrong-option analysis: Deep Alluvial Soil: northern plains; Saline soil: Rann of Kutch/coastal areas; Desert soil: western Rajasthan arid zone.

Correct Answer: A. Hilly regions

• **Contour Bunding in hilly regions** = building embankments along natural contours of slopes to catch rainwater and prevent topsoil runoff. • **Catching rainwater on slopes** — the primary function of contour bunding that reduces erosion and retains soil moisture. • 💡 Wrong-option analysis: Dry regions: shelter belts and check dams are used; Deltaic regions: embankments for flood management; Coastal regions: mangrove planting and seawalls.

Correct Answer: A. Alluvial Soil

• **Alluvial soil = rich in Potash but poor in Phosphorus** = also rich in lime but deficient in phosphorus and nitrogen, requiring minor fertilization. • **Most productive soil in India** — despite minor nutrient gaps, alluvial soil's overall fertility makes it India's most agriculturally productive soil. • 💡 Wrong-option analysis: Black soil: rich in lime/calcium/magnesium but deficient in N/P/humus; Arid soil: rich in phosphate but low in nitrogen; Laterite soil: deficient in major nutrients due to leaching.