Soils of Tamil Nadu
The soils in Tamil Nadu are broadly classified into five types according to their characteristics. They are 1. alluvial soil, 2. black soil, 3. red soil, 4. laterite soil, 5. saline soil.
Alluvial soils are formed by the deposition of silt by the rivers. It is found in the river valley regions and the coastal plains of Tamil Nadu. Generally this type of soil is found in the districts of Thanjavur, Tiruvarur, Nagapattinam, Villupuram, Cuddalore, Tirunelveli and Kanyakumari. It is also found to a small extent along the river valleys in few interior districts.
Black soils are formed by the weathering of igneous rocks. It is also known as regur soil. As cotton grows well in this soil, it is also called as black cotton soil. Black soils are found extensively in the districts of Coimbatore, Madurai, Virudhunagar, Tirunelveli and Thoothukudi.
Red soils cover over two-thirds of the total area of Tamil Nadu. They are found particularly in the central districts of the state. It is dominantly found in Sivagangai and Ramanathapuram districts.
This soil is formed by the process of intense leaching. Laterite soils are found in some parts of Kancheepuram, Tiruvallur and Thanjavur districts and some patches over the mountainous region in the Nilgiris.
Saline soils in Tamil Nadu are confined to the Coromandel coast. Vedaranyam has a pocket of saline soil. However, the tsunami waves on December 26, 2004 brought a lot of sand and deposited it all along the east coast of Tamil Nadu. The tsunami made the coastal areas unsuitable for cultivation to a considerable extent.