Soil Distribution In India

The soils of India are generally very old and fully matured and there formation is due to seasonal climatic distribution and amount of rainfall . India has a combined form of tropical and temperate climatic conditions and if we talk about the rainfall we can conclude with 20 to 400 cm annual .

On general basis soil in India can be classified as Alluvial , Black cotton , Red Soils , Laterite , Forest and hill , Arid and desert , Peaty and marshy soils etc . But here our main focus is on classification of soil on the basis of geotechnical engineering . Hence : -

1. Marine Deposits 

These deposits are very soft and highly compressible consolidated clay . Thickness of deposits varies in the range of 5 m to 20 m . Deposits consist of a medium senstive soil . These deposits undergoes pre treatment before applying any external load .  From the name it is clear that these deposits are found at the coastal plains like Andhra Pradesh , Tamil Nadu , Goa , Pondicherry , Kerala , Maharashtra , Gujarat and West Bengal .   

2. Black Cotton Soil 

It is spread over an area of 3,00,000 sq km . Montmorrillonite and Illite clay minerals are present in the deposit which makes them expansive soil . Primary rock is Basalt . The depth of black cotton soil ca be as high as 20  m . These deposits are found in the area like Maharashtra , Karnataka , Madhya Pradesh , Andhra Pradesh , Uttar Pradesh , Tamil Nadu . 

3. Lateritic Soil / Murrums 

Tropical regions of high moisture along with high temperature leads to development of soil type identified as laterite . A coarse grained with 90% of these lateritc constituents is laterite , while those of fine grained with low concentraion of oxides called lateritc soils . Major places are Kerala , Karnataka , Maharashtra , Orissa  and West Bengal states .
Murrums are residual soils formed from basaltic rock where monsoon is severe .

4. Alluvial Soils 

These are in Indo-Gangatic and Brahmaputra flood plains . Thickness of deposits are about 100 m . Ranging from Assam in East to Punjab in west alluvial deposits are found . Bengal basin is another important alluvial deposit , and it is assumed that these deposits were formed in the middle of Mesozoic era . These Bengal basin deposit is formed by Ganga river and upper subsoil strata is of 100 m . 

5. Desert Soil 

From the name it is clear that we are talking about Rajasthan and it covers about 5,00,000 sq km . Average height is of 15 m and these are wind blowns and are collected in the form of sand dunes . Problems associated with the soil are of soil stabilization for road construction .

6.   Boulder Deposit 

Large boulders are carried down hills due to rivers and deposited near foot hills . Such deposits are encountered in the sub-Himalayan regions of Himachal Pradesh and Uttar Pradesh . The properties of these deposits are complex and depend on the size of boulders and soil matrix . 

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