Red soils (Acrisols)
Ancient crystalline and metamorphic rocks have given rise to red soils. These soils are found predominantly in the states of Andhra Pradesh, Tamil Nadu, Karnataka, Maharashtra, Orissa, Goa and in the northeastern states. They have limitations of soil depth, poor water and nutrient-holding capacity, excessive drainage, runoff and are generally poor in N, P, zinc (Zn), sulphur (S) and humus. Under good management, these soils can be used profitably for a variety of crops such as millets, rice, groundnut, maize, soybean, pigeon pea, green gram, jute, tea, cashew, cocoa, grapes, banana, papaya and mango.
Laterite and lateritic soils are deeply weathered soils with a high clay content, having low base and silica owing to pronounced leaching. They are generally found in Kerala, Tamil Nadu, Karnataka, Andhra Pradesh and the northeastern region, and occupy about 25 million ha. The major limitations posed by these soils include deficiency of P, potassium (K), calcium (Ca), Zn and boron (B), high acidity and toxicity of aluminum (Al) and manganese (Ma). The important crops grown on these soils are rice, banana, coconut, areca nut, cocoa, cashew, coffee, tea and rubber.
Desert (arid) soils (Arenosols, Calcisols and Gypsisols)
Desert soils constitute the soils with negligible vegetation in both hot and cold regimes. They cover an area of about 29 million ha. The sandy material results in poor profile development under arid conditions. Water deficiency is the major constraint in cultivating these soils. A gypsic horizon is common in extremely arid areas such as Bikaner and Jaisalmer in Rajasthan. These soils are very prone to wind erosion.
Forest and hill soils are found at high as well as low elevations where rainfall is sufficiently high to support forest growth. Soil formation is governed mainly by the deposition of organic matter derived from the forest growth. Brown forest and Podzolic soils are common in the Northern Himalayas, while the Deccan Plateau forests have red and lateritic soils.
Saline and sodic soils occur under semi-arid conditions and occupy an area of 10 million ha. They are widely distributed in Rajasthan, Punjab, Haryana, Uttar Pradesh, Madhya Pradesh, Maharashtra and Gujarat. The sodic soils pose serious problems of a high sodium (Na) content, poor physical conditions and nutrient deficiency. Despite many limitations, once ameliorated using gypsum, sodic soils are used successfully for growing rice followed by wheat.
Peaty and marshy soils are formed by plants growing in the humid regions under permanently waterlogged conditions. They are found in Kerala, Orissa, West Bengal (Sundarbans) and along the South-East coast of Tamil Nadu. Where properly drained and fertilized, these soils often produce a very good rice crop.
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