MCQs on Soils of India for UPSC and State PSC exams

Pedogenesis involves physical, chemical, biological weathering of parent rock plus humus addition, influenced by climate, organisms, relief, parent material, time.

ICAR recognizes 8 major groups based on genesis, colour, texture, based on USDA taxonomy adaptation.

Transported soils deposited by Indus, Ganga, Brahmaputra and peninsular rivers in floodplains, deltas, coastal plains.

Largest soil group, about 15 lakh sq km, covering Northern Plains, deltas, coastal strips, most fertile.

Khadar is newer floodplain alluvium renewed annually, fertile; Bhangar is older terrace alluvium with kankar nodules, less fertile.

Found in low-lying floodplains, fine texture, high water retention, ideal for paddy, wheat, sugarcane.

Older alluvium at higher terraces, coarser, contains concretions, less fertile than Khadar.

Generally rich in potash and lime, but need nitrogenous fertilizers for intensive cropping.

Derived from Marathi ‘regur’ meaning cotton soil, formed from basalt weathering, ideal for cotton.

Formed in situ from Deccan Trap basalt, also from gneiss in Tamil Nadu, rich in clay minerals.

Cover Deccan Plateau, about 5.5 lakh sq km, in lava plateau region.

Montmorillonite clay causes self-ploughing, deep cracks in summer aid aeration, high moisture retention.

Deficient in nitrogen, phosphorus, humus, but fertile for cotton, sorghum, soybean due to moisture retention.

Cracks in dry season allow self-tillage, reduces need for ploughing.

Develop on ancient granite, gneiss, schist under oxidizing conditions, widespread in peninsular India.

Iron compounds oxidize in warm dry climate, giving reddish hue; yellow when hydrated.

Cover about 18% of India, second largest group after alluvial.

Low fertility, need fertilizers, suitable for millets, pulses, oilseeds with irrigation.

Process of laterization removes silica, leaves iron and aluminium oxides, forms under alternating wet-dry tropical climate.

High rainfall >200 cm, high temperature causes leaching, soils become acidic and infertile.

Poor in lime, silica, organic matter, suitable for plantation crops like tea, coffee, cashew with manure.

Soft when wet, hardens on exposure, used in Goa, Kerala for construction.

Formed in arid climate with high evaporation, low rainfall <50 cm.

Light colour, poor water retention, high soluble salts, need irrigation for cultivation.

With irrigation (Indira Gandhi Canal), wheat and cotton grown.

Contain excess salts sodium, magnesium, calcium, unfit for agriculture without reclamation.

Found in canal-irrigated areas of Punjab, Haryana, UP, also in Sundarbans and Rann of Kutch.

Gypsum replaces sodium, flushing with water removes salts, growing salt-tolerant crops like barley.

Formed in waterlogged areas with high organic matter, anaerobic conditions.

Black, heavy, contain 10-40% organic matter, formed by decaying vegetation in swamps.

Found in Kuttanad below sea level, reclaimed for rice cultivation.

Vary with altitude, thin, immature, acidic in high rainfall areas, rich in humus in valleys.

Erosion prevents development, but valley soils (Karewas) support orchards.

Water erosion (sheet, rill, gully) in Himalayas and Deccan; wind erosion in Rajasthan.

Forms badlands due to soft alluvium and deforestation, called ravines.

Most dangerous as unnoticed, reduces fertility across large areas.

Removes fine particles, forms sand dunes, reduces soil fertility.

Mechanical and biological measures reduce runoff and wind speed.

Ploughing along contours slows runoff, increases infiltration.

Rows of trees planted to break wind speed, e.g., in Rajasthan.

pH 6.5-7.5, suitable for most crops.

pH 7.2-8.5 due to lime content.

Due to leaching of bases, need lime application.

pH 5.5-7.0, low base saturation.

High fertility and irrigation support intensive agriculture in Indo-Gangetic plain.

Moisture retentive, ideal for dryland cotton cultivation.

With irrigation and fertilizers, can grow groundnut, ragi.

In Kerala, Karnataka, Assam hills after adding manure.

Indira Gandhi Canal transformed parts of Thar.

Uses 10 orders, adapted to Indian conditions, scientific classification.