Soil is one of the most important natural resources. India's varied natural environments have produced a great variety of soils, and rich, deep, fertile soils support a high density of population through agricultural prosperity. This chapter covers India's soils, irrigation and multipurpose projects, types of farming, major crops, livestock, fisheries and the problems of farmers.
1. Soils of India
Soil is the uppermost layer of the land surface, composed of minerals, organic matter, living organisms, air and water. Its grains are of three categories: clay, silt and sand. Soils are mostly formed by the weathering of rocks. The Indian Council of Agriculture Research (ICAR) divides Indian soils into eight major groups.
| Soil | Key Characteristics | Distribution | Crops |
|---|---|---|---|
| Alluvial | Deposited by rivers; Khadar light coloured, Bhangar older and dark; rich in potash, poor in nitrogen | Ganga and Brahmaputra valleys; plains of Uttar Pradesh, Punjab, Haryana, West Bengal, Bihar | Rice, wheat, sugarcane, oilseeds |
| Black | Derived from basalts of Deccan trap; black due to titanium and iron; sticky when wet; high moisture retentivity | Maharashtra and Malwa plateaus, Kathiawar, Telangana, Rayalaseema, northern Karnataka | Cotton, millets, tobacco, sugarcane |
| Red | From ancient crystalline rocks like granites and gneisses; rich in iron and magnesium; light, porous | Eastern Deccan, Kerala, Tamil Nadu, Karnataka, Chota Nagpur plateau | Wheat, rice, cotton, sugarcane, pulses |
| Laterite | Formed by leaching under alternate wet and hot dry conditions; hydrated oxides of iron and aluminium | Assam hills, hill summits of Kerala and Karnataka, Eastern Ghats, Odisha | Coffee, rubber, cashewnut, tapioca |
| Forest and mountain | Mechanical weathering; very rich in humus; acidic | Coniferous belts of Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Sikkim | Coffee, tea, rice, maize, potato, spices |
| Arid and desert | Dry, low humus, high soluble salts; rich in phosphate, poor in nitrogen | Rajasthan, Northern Gujarat, southern Punjab | Millets, barley, cotton (with irrigation) |
| Saline and alkaline | Ill drainage and water logging; salts rise by capillary action | Drier parts of Bihar, Uttar Pradesh, Haryana, Punjab, Rajasthan, Maharashtra | Crops do not grow |
| Peaty and marshy | From organic matter in humid regions; black, heavy, highly acidic | Kottayam and Alappuzha (Kerala), Sundarbans, coastal Odisha and Tamil Nadu | Paddy, jute |