Major soil deposits of India

There are seven soil deposits in India. They are alluvial soil, black soil, red soil, laterite soil, or arid soil, and forest and mountainous soil, marsh soil. These soils are formed by various geographical factors. They also have varied chemical properties. Sundarbans mangrove swamps are rich in marsh soil.

Alluvial Soil
The rivers deposit very fine particles of soil in different parts of India. This type of soil is widespread in the Northern Plains of India. Alluvial soils are rich in humus as they are deposited by three important monkey river of Himalayas, Indus River, Ganges and Brahmaputra River. They are found in the eastern coastal plains of India, particularly in the deltas of rivers Mahanadi, Godavari River, Krishna River and Kaveri. These are generally rich in Phosphoric acid, lime and potash, and is well known for its water holding capacity which makes it ideal for growing sugarcane, paddy, wheat and other cereal crops.colour of alluvial soil is light grey or ash grey

Mountain soils
Mountain soils are found in the valleys and hill slopes of the Himalayas at altitudes of 2500 m to 3000 m. These soils are often the vegetation cover helps in their classification. The carbon nitrogen ratio is very wide. They are silty loam to loam in texture and dark brown in colour.

Desert soils
These soils are found in Thar desert in the Indian state of Rajasthan and Gujarat. This soil is formed from arid condition with practically negligible rainfall. This type of soil is highly pervious and have a low density. It requires densification to increase its bearing capacity and shearing strength. Commonly recognised plants that grow in these soils are cacti.

Black soils
This type of soil is black in colour. These soils are also called as regur soils. In the north-western found Deccan Plateau. The soil is suitable for growing cottons, due to which it is also known as black cotton soil. It is believed that the climatic conditions along with the parent rock material are the important factors for the formation of black soil. This type of soil is typically of the Deccan trap region spread over Northwest Deccan plateau and is made from lava flows. They cover the plateaus of Maharashtra, Saurashtra, Malwa, Madhya Pradesh, Chhattisgarh and extend in South-East direction along Godavari and Krishna valleys. These soils contain essential clay minerals as montmorillonite. These soils cover an extensive area of 300,000 square kilometres. The engineering properties of such soils are as follows: They are made up of clayey materials. They are well known for their capacity to hold moisture. They are rich in calcium carbonate, magnesium, potash and lime. During summer, they develop crack. This is very helpful for aeration of black soil.
 * High compressibility
 * Low bearing capacity
 * Low shearing strength

Red Soils
Red soil is a type of soil that develops in a warm, temperate, moist climate under deciduous or mixed forest, having thin organic and organic-mineral layers overlying a yellowish-brown leached layer resting on an illuvium red layer. Red soils are generally derived from crystalline rock. They are usually poor growing soils, low in nutrients and humus and difficult to cultivate because of its low water holding capacity.

Laterite soils
Laterite soils are formed from chemical decomposition of rocks. soils mainly contain iron oxide which gives them characteristic pink or red color. These soils are found in Central,Eastern and Southern India. These are residual soils is formed from basalt and have high specific gravity. These soils are mostly composed as calcite depositions. They are more suitable for crops like cashew nut.

Marine deposits
These soils are found in narrow belt near the south-west coast of India. These soils have low shearing strength and high compressibility. The marine clays are soft and highly plastic. They contain large amount of organic matter and are not suitable for construction of megastructures like buildings, cranes etc.