Soils: Alluvial, Black, Red and Yellow

Indian soils are categorised geologically into peninsular and extra-peninsular soils. Peninsular India’s soils are generated via in situ decomposition of rocks, i.e. decomposition of rocks directly from the underlying rocks. 

Even though it was not as detailed as current categories, soil in India has been classed from ancient times.

The categorization was based on only two factors in the ancient period: whether the soil was fruitful or sterile. As a result, the categorization was 

• Urvara [fertile]

• Usara [sterile]

Alluvial Soils:

The alluvial soil is a commonly found soil that mainly occurs in the Satluj- Ganga- Brahmaputra Plains. The alluvial soil is also found in valleys of the Narmada, Tapi, and the Eastern and Western coastal plains. This soil is poorly drained and well-drained with an immature profile in undulating areas. The alluvial soil lacks phosphorus. The colour of the soil varies from light grey to ash. It is great for the cultivation of wheat, Rice, maize, oilseeds, sugarcane, etc.

• The alluvial soil is mainly found in the river valleys and the northern plains. It covers around 40% of India’s total area. Alluvial soils are depositional soils transported and deposited by streams and rivers
• Alluvial soils are found in the river valleys and the east coast deltas in the Peninsular region
• They are present in Rajasthan, leading to some parts of Gurjrat through a narrow corridor
• They contain a high percentage of potash and are generally poor in phosphorus
• They can be anywhere from sandy loam to clay in nature 
• In the Ganga plain, two alluvial soil types are known as Khadar and Bhangar 
• Khadar gets deposited due to annual floods, which improves soil fertility due to the deposition of fine silts

The Bhangar and Khadar soils contain many calcareous concretions, commonly known as Kankars

• These soils are loamier and more clayey in the Brahmaputra valley and the lower and middle Ganga plain
• Its shades depend on various factors, including the material texture, deposition depth, and the time taken to attain maturity  
• The colour varies anywhere from light grey, grey to ash grey 
• These are intensively cultivated

Black Soil:

Also known as cotton soil or the Tropical Chernozems, the black soil is the third largest soil in India. The black soil is mainly formed from the rocks of cretaceous lava. The soil is mainly found in areas like Gujarat, North- Western Andhra Pradesh, Western parts of Madhya Pradesh, Tamil Nadu, Maharashtra, Chhattisgarh, Karnataka, Rajasthan, Jharkhand up to Raj Mahal hills. The soil is extremely rich in calcium, potash, magnesium, iron, lime, and aluminium. Black soil has high water content and excellent cultivation of Tobacco, cotton cultivation, castor, citrus fruits, and linseed.

• Black soil is mainly found in the Deccan Plateau and parts of Madhya Pradesh, Maharashtra, Gujarat, certain areas of Tamil Nadu, and Andhra Pradesh  
• Black soil is profoundly found in the Krishna and the Godavari rivers
• Black soil is also termed the ‘Black Cotton Soil’ or the “Regular Soil 
• They appear to be profound, clayey, and impermeable
• Once wet, it becomes sticky and swells and shrinks once it dries
• During December to March, black soil develops massive cracks, which lead to a kind of ‘self-ploughing
• Loss of moisture and slow absorption, the black soil gets moisture for a prolonged period, which helps the rain-fed crops to survive even when there is no adequate rainfall
• Black soils contain lime, magnesia, alumina, and iron. They also have a higher percentage of potash. However, they are deficient in organic matter, phosphorus, and nitrogen

Red and Yellow Soil:

The red soil is mainly developed on Archean granite and occupies a larger area of the country. From Tamil Nadu in the south to Raj Mahal in the east, and from Bundelkhand in the north to Kathiawad in the west, this soil may be found in abundance. The omnibus group is another name for the red soil. Due to the presence of ferric oxides, it has a red colour. The horizons of the soil is yellow whereas the top layer is red. Generally, these soils lack magnesia, phosphate, nitrogen, lime, humus. This soil is great for the cultivation of pulses, wheat, cotton, millets, potato, orchards, tobacco and oilseeds.

• Red soil is majorly found on the crystalline igneous rocks in areas that witness low rainfall, including the various parts of the Deccan Plateau. It also includes the Western Ghats
• Yellow and red soil is also found in significant parts of Chhattisgarh and Odisha and the southern region of the Ganga plain
• Due to a wide diffusion of iron, the soil appears to be reddish
• In hydrated form, the soil appears bright yellow
• The finely-grained red soil enjoys a high percentage of soil fertility; however, coarse-grained soils have low fertility 
• Red and yellow soil are generally poor in phosphorus, nitrogen, and humus

Conclusion 

Alluvial, Black, Red and Yellow Soil is commonly found in different parts of India. Out of all, alluvial soil is the most extensive soil found in India. Soils were divided into two types in ancient times: Urvara and Usara, which were productive and sterile, respectively. Soils were classed in mediaeval times based on exterior characteristics such as texture, colour, land slope, and moisture composition of the soil. As a result, the soils were classified as sandy, clayey, silty, and loamy, among other things.