Soils: Type of Indian Soils
There is a wide range of soil types in India. As products of natural environmental processes, they can be broadly divided into two groups: in situ soils and transported soils. The in situ soils get their distinguishing features from the parent rocks, which are sieved by flowing water, sliding glaciers, and drifting wind and are deposited on landforms such as river valleys and coastal plains. The process of sieving such soils has led to deposition of materials in layers without any marked pedologic horizons, though it has altered the original chemical composition of the in situ soils.Among the in situ soils are the red-to-yellow (including laterite) and black soils known locally as regur. After those the alluvial soil is the third most-common type. Also significant are the desert soils of Rajasthan, the saline soils in Gujarat, southern Rajasthan, and some coastal areas, and the mountain soils of the Himalayas. The type of soil is determined by numerous factors, including climate, relief, elevation, and drainage, as well as by the composition of the underlying rock material.
There is a wide range of soil types in India. As products of natural environmental processes, they can be broadly divided into two groups: in situ soils and transported soils. The in situ soils get their distinguishing features from the parent rocks, which are sieved by flowing water, sliding glaciers, and drifting wind and are deposited on landforms such as river valleys and coastal plains. The process of sieving such soils has led to deposition of materials in layers without any marked pedologic horizons, though it has altered the original chemical composition of the in situ soils.
Among the in situ soils are the red-to-yellow (including laterite) and black soils known locally as regur. After those the alluvial soil is the third most-common type. Also significant are the desert soils of Rajasthan, the saline soils in Gujarat, southern Rajasthan, and some coastal areas, and the mountain soils of the Himalayas. The type of soil is determined by numerous factors, including climate, relief, elevation, and drainage, as well as by the composition of the underlying rock material.
In situ soils
Red-to-yellow soils
Those soils are encountered over extensive non alluvial tracts of peninsular India and are made up of such acidic rocks as granite, gneiss, and schist. They develop in areas in which rainfall leaches soluble minerals out of the ground and results in a loss of chemically basic constituents; a corresponding proportional increase in oxidized iron imparts a reddish hue to many such soils. Hence, they are commonly described as ferralitic soils. In extreme cases, the concentration of oxides of iron leads to formation of a hard crust, in which case they are described as lateritic (for later, the Latin term meaning “brick”) soils. The heavily leached red-to-yellow soils are concentrated in the high-rainfall areas of the Western Ghats, the western Kathiawar Peninsula, eastern Rajasthan, the Eastern Ghats, the Chota Nagpur plateau region, and other upland tracts of northeastern India. Less-leached red-to-yellow soils occur in areas of low rainfall immediately east of the Western Ghats in the dry interior of the Deccan. Red-to-yellow soils are usually infertile, but that problem is partly ameliorated in forested tracts, where humus concentration and the recycling of nutrients help restore fertility in the topsoil.Black soils
Among the in situ soils of India, the black soils found in the lava-covered areas are the most conspicuous. Those soils are often referred to as regur but are popularly known as “black cotton soils,” since cotton has been the most common traditional crop in areas where they are found. Black soils are derivatives of trap lava and are spread mostly across interior Gujarat, Maharashtra, Karnataka, and Madhya Pradesh on the Deccan lava plateau and the Malwa Plateau, where there is both moderate rainfall and underlying basaltic rock. Because of their high clay content, black soils develop wide cracks during the dry season, but their iron-rich granular structure makes them resistant to wind and water erosion. They are poor in humus yet highly moisture-retentive, thus responding well to irrigation. Those soils are also found on many peripheral tracts where the underlying basalt has been shifted from its original location by fluvial processes. The sifting has only led to an increased concentration of clastic contents.
Those soils are encountered over extensive non alluvial tracts of peninsular India and are made up of such acidic rocks as granite, gneiss, and schist. They develop in areas in which rainfall leaches soluble minerals out of the ground and results in a loss of chemically basic constituents; a corresponding proportional increase in oxidized iron imparts a reddish hue to many such soils. Hence, they are commonly described as ferralitic soils. In extreme cases, the concentration of oxides of iron leads to formation of a hard crust, in which case they are described as lateritic (for later, the Latin term meaning “brick”) soils. The heavily leached red-to-yellow soils are concentrated in the high-rainfall areas of the Western Ghats, the western Kathiawar Peninsula, eastern Rajasthan, the Eastern Ghats, the Chota Nagpur plateau region, and other upland tracts of northeastern India. Less-leached red-to-yellow soils occur in areas of low rainfall immediately east of the Western Ghats in the dry interior of the Deccan. Red-to-yellow soils are usually infertile, but that problem is partly ameliorated in forested tracts, where humus concentration and the recycling of nutrients help restore fertility in the topsoil.
Black soils
Among the in situ soils of India, the black soils found in the lava-covered areas are the most conspicuous. Those soils are often referred to as regur but are popularly known as “black cotton soils,” since cotton has been the most common traditional crop in areas where they are found. Black soils are derivatives of trap lava and are spread mostly across interior Gujarat, Maharashtra, Karnataka, and Madhya Pradesh on the Deccan lava plateau and the Malwa Plateau, where there is both moderate rainfall and underlying basaltic rock. Because of their high clay content, black soils develop wide cracks during the dry season, but their iron-rich granular structure makes them resistant to wind and water erosion. They are poor in humus yet highly moisture-retentive, thus responding well to irrigation. Those soils are also found on many peripheral tracts where the underlying basalt has been shifted from its original location by fluvial processes. The sifting has only led to an increased concentration of clastic contents.
Alluvial soils
Alluvial soils are widespread. They occur throughout the Indo-Gangetic Plain And along the lower courses of virtually all the country’s major rivers (especially the deltas along the east coast). The non deltaic plains along India’s coasts are also marked by narrow ribbons of alluvium.New alluvium found on much of the Indo-Gangetic floodplain is called khadarand is extremely fertile and uniform in texture; conversely, the old alluvium on the slightly elevated terraces, termed bhangar, carries patches of alkaline efflorescences, called usar, rendering some areas infertile. In the Ganges basin, sandy aquifers holding an enormous reserve of groundwater ensure irrigation and help make the plain the most agriculturally productive region of the country.
Alluvial soils are widespread. They occur throughout the Indo-Gangetic Plain And along the lower courses of virtually all the country’s major rivers (especially the deltas along the east coast). The non deltaic plains along India’s coasts are also marked by narrow ribbons of alluvium.
New alluvium found on much of the Indo-Gangetic floodplain is called khadarand is extremely fertile and uniform in texture; conversely, the old alluvium on the slightly elevated terraces, termed bhangar, carries patches of alkaline efflorescences, called usar, rendering some areas infertile. In the Ganges basin, sandy aquifers holding an enormous reserve of groundwater ensure irrigation and help make the plain the most agriculturally productive region of the country.
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