Soils of India
Soil questions are very common in prelims and state PSCs (soil type, region, crop, characteristics). Soil is formed by parent rock, climate, relief, organisms and time. The ICAR classification of soils is the standard, and the National Bureau of Soil Survey and Land Use Planning (NBSS&LUP, Nagpur) is the key institute.
Major soil groups at a glance
| Soil | Share of area (approx.) | Colour / texture | Main areas | Crops | Features |
|---|---|---|---|---|---|
| Alluvial | About 40+ percent | Grey to light brown; sand, silt, clay | Northern plains, east coast deltas, Gujarat plain | Wheat, rice, sugarcane, jute, pulses | Very fertile; rich in potash and lime; poor in nitrogen and humus |
| Black (Regur) | About 15 percent | Black, clayey | Maharashtra, Madhya Pradesh, Gujarat, parts of Karnataka, Telangana, Andhra | Cotton, soybean, sugarcane, millets | Self-ploughing, high moisture retention, cracks in summer, rich in iron, lime, magnesium |
| Red and yellow | About 18 percent | Red because of iron oxide; sandy to loamy | Tamil Nadu, Karnataka, Andhra, Odisha, Chhattisgarh, Jharkhand, Eastern MP | Millets, groundnut, pulses, tobacco, potato | Poor in nitrogen, phosphorus, humus; porous |
| Laterite | About 3-4 percent | Reddish brown; hard when dry | Western Ghats, Eastern Ghats, Meghalaya, Kerala, Karnataka, Odisha, Assam | Tea, coffee, rubber, cashew, tapioca | Formed by leaching in heavy rain; acidic, low fertility |
| Arid (desert) | About 4 percent | Sandy, saline | Rajasthan, Kutch, parts of Haryana and Punjab | Millets, barley with irrigation | Low humus, high salts, kankar layers below |
| Saline and alkaline | Small | White salt crusts | Rajasthan, Punjab, Haryana, Uttar Pradesh, Gujarat, Maharashtra, Sunderbans | Not suited | Local names reh, kallar, usar, thur |
| Peaty and marshy | Small | Dark, heavy, acidic | Kerala (Kuttanad), Sundarbans, Odisha coast, Bihar and Uttarakhand | Rice in Kuttanad | Rich in organic matter, high acidity |
| Forest and mountain | About 8 percent | Brown, varied | Himalayan slopes, Western Ghats, Eastern Ghats | Tea, coffee, orchards, spices | Loamy in valleys, coarse on slopes; acidic in places |
Alluvial soils in detail
- Khadar: new, fertile alluvium of the flood plains, renewed every year.
- Bhangar: old alluvium of the higher terraces, with kankar nodules; less fertile.
- Bhabar, Terai: the foothill belt zones (see Northern Plains).
- Fertile for the wheat belt of Punjab-Haryana and the rice belt of the east.
Black soil
- Formed from basalt (Deccan Trap) weathering.
- Regur from the Telugu word regada; cotton soil.
- Becomes sticky when wet and cracks when dry, so the soil is self-ploughing.
Laterite
- The word comes from Latin later (brick). Used for building bricks.
- Forms in tropical areas with alternate wet and dry seasons.
Soil erosion and conservation
- Sheet erosion: thin layer removed by water. Gully erosion: deep channels; ravines in the Chambal, Yamuna and Mahi (Chambal ravines are famous). Wind erosion in Rajasthan.
- Methods: contour ploughing, terracing, strip cropping, shelter belts, check dams, afforestation.
- Shifting cultivation (jhum) in the north-east causes erosion.
- Soil Health Card scheme (2015): gives farmers a report on soil nutrients.
- Soil Health Mission under the National Mission for Sustainable Agriculture.
- Central Soil Salinity Research Institute, Karnal; ICAR-Indian Institute of Soil Science, Bhopal.
- World Soil Day: 5 December.
Keep practising
Notes are only half the work. Test yourself with questions and discuss doubts with other aspirants.
Prepared for exam revision from NCERT, standard geography textbooks, the Census of India 2011, the India State of Forest Report, IMD, Ministry of Agriculture and other official sources. Maps are schematic teaching maps, not Survey of India maps, and zone boundaries are approximate. Figures such as production, capacity, counts of parks and ports, and census status change, so check the latest official source before relying on them. Found a mistake? Tell us.