S OILS C H A P T E R sandy, clayey, silty and loam, etc. On the basis of colour, they were red, yellow, black, etc. Since Independence, scientific surveys of soils have been conducted by various agencies. Soil Survey of India, established in , made comprehensive studies of soils in selected areas like in the Damodar Valley.
The National Bureau of Soil Survey and the Land Use Planning an Institute under the control of the Indian Council of Agricultural Research (ICAR) did a lot of studies on Indian soils. In their effort to study soil and to make it comparable at the international level, the ICAR has classified the Indian soils on the basis of their nature and character as per the United States Department of Agriculture (USDA) Soil Taxonomy. ICAR has classified the soils of India into the following order as per the USDA soil taxonomy Sl. Order Area Percentage No.
(in Thousand Hectares) Inceptisols 130372. . Entisols 92131. .
Alfisols 44448. . Vertisols 27960. .
Aridisols 14069. . Ultisols . .
Mollisols . . (viii) Others . .
Total Source : Soils of India, National Bureau of Soil Survey and Land Use Planning, Publication Number On the basis of genesis, colour, composition and location, the soils of India have been classified into: Alluvial soils Black soils Red and Yellow soils Laterite soils Arid soils Saline soils (vii) Peaty soils (viii) Forest soils. Alluvial Soils Alluvial soils are widespread in the northern plains and the river valleys. These soils cover about per cent of the total area of the country. They are depositional soils, transported and deposited by rivers and streams.
Through a narrow corridor in Rajasthan, they extend into the plains of Gujarat. In the Peninsular region, they are found in deltas of the east coast and in the river valleys. The alluvial soils vary in nature from sandy loam to clay. They are generally rich in potash but poor in phosphorous.
In the Upper and Middle Ganga plain, two different types of alluvial soils have developed, viz. Khadar and Bhangar . Khadar