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 the sediments brought down by the rivers. They also have varied chemical properties. Sundarbans mangrove swamps are rich in marsh soil.
Major soil deposits
| Soil deposit | Description | Image |
|---|---|---|
| Alluvial soil | Alluvial soil have been deposited by the Indus, the Ganges, and the Brahmaputra rivers. The entire northern plains (including parts of Arunachal Pradesh, Assam, Bihar (Almost entirely), Chandigarh, Delhi (almost entirely), Haryana, Himachal Pradesh, Madhya Pradesh, Punjab, Rajasthan, Uttarakhand, Uttar Pradesh, and West Bengal) are made of alluvial soil. These soil also extend in Rajasthan and Gujarat through a narrow corridor. It is also found in the eastern coastal plains particularly in the deltas of Mahanadi, the Godavari, the Krishna, and the Kaveri rivers. Alluvial soil as a whole are very fertile. Mostly these soils contain adequate proportion of potash, phosphoric acid and lime which are ideal for the growth of sugarcane, paddy, wheat, and other cereal and pulse crops. |
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| Black soil | Black soil is typical of the Deccan trap (Basalt) region spread over northwests Deccan plateau and is made up of lava flows. They cover the plateaus of Maharashtra, Saurashtra, Malwa, Madhya Pradesh, and Chattishgarh and extend in the south-east direction along the Godavari and the Krishna valleys. Also known as regur soil, black soil is ideal for growing cotton and is known as black cotton soil. They are rich in soil nutrients, such as calcium carbonate, magnesium, potash and lime. These soils are generally poor in phosphoric contents. The black soils are made up of clayey soil, well known for their capacity to hold moisture. 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. |
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| Red and yellow soil | Red soil develops on crystalline igneous rocks in areas of low rainfall in the eastern and southern parts of the Deccan plateau. Yellow and red soils are also found in parts of Odisha, Chhattisgarh, West Bengal, Maharashtra, southern Karnataka, Tamil Nadu, Madhya Pradesh. Red and yellow soils develop a reddish colour due to diffusion of iron in crystalline and metamorphic rocks. It looks yellow when it occurs in a hydrated form. | |
| Laterite soil | Laterite soils are mainly found in Karnataka, Kerala, Tamil Nadu, Madhya Pradesh, Andhra Pradesh and the hilly areas of Odisha and Assam. After adopting appropriate soil conservation techniques particularly in the hilly areas of Karnataka, Kerala and Tamil Nadu, this soil is very useful for growing tea and coffee. Red laterite soils in Tamil Nadu, Andhra Pradesh and Kerala are more suitable for crops like cashew nut.
The laterite soil develops in areas with high temperature and heavy rainfall. This is the result of intense leaching due to heavy rain. Humus content of the soil is low because most of the microorganisms, particularly the decomposers, like bacteria, get destroyed due to high temperature and lack of organic matter which is food, shelter and protection for the microorganisms from the high temperatures. Laterite soils are suitable for cultivation. |
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| Arid soil | Arid soils range from red to brown in colour. They are generally sandy in texture and saline in nature. In some areas the salt content is very high and common salt is obtained by evaporating the water. Due to the dry climate, high temperature, evaporation is faster and the soil lacks organic matter and moisture which is the raw material needed for humus. The lower horizons of the soil are occupied by Kankar because of the increasing calcium content downwards. The Kankar layer formations in the bottom horizons restrict the infiltration of water. After proper irrigation these soils become cultivable as has been in the case of western Rajasthan. | |
| Forest soil | Forests soils are found in the hilly and mountainous areas where sufficient rainforests are available. The soils texture varies according to the mountain environment where they are formed. The soil is loamy and silty in valley sides and coarse-grained in the upper slopes. It is acidic with low humus content in the snow covered areas.
Alluvial SoilThe 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. Mountain soilsMountain soils are found in the valleys and hill slopes of the Himalayas at altitudes of 2500 m to 3000 m. These soils are least studied and 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 soilsThese 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 soilsThis 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 develops crack. This is very helpful for aeration of black soil. Red SoilsRed 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 soilsLaterite 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 depositsThese 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. |
