Soil is the topmost layer of the earth's crust which is a mixture of fine powdered rocks, organic matter, liquids, myriad organisms and other minerals. The proportion of the key ingredients determines the type of soil. But, factors such as vegetation, climatic conditions, human activities for e.g. grazing, farming, gardening etc also influence soil formation. In India, various types of soils are found and their formations are influenced by certain factors such as altitude, climate, disproportionate rainfall and many others. The type of soil differs in different areas of the country. There are lots of questions being asked related to types of soils in various exams like UPSC, State PSCs, SSC and various other exams.
Soil Classification – Urvara vs Usara
Earlier soil was mainly classified in two types based on the fertility of soil which are as below:-
- Urvara:- fertile soil
- Usara' non-fertile or sterile soil
Types of soils in India:-
As now a days there are lots of characteristics of soil are taken into consideration before its classification such as texture, colour, moisture content etc. In the year 1956, Soil survey of India, an institution was established by The Government of India to study soil and its characteristics. There are six major type of soil found in india:
- Alluvial Soils
- Black Soils
- Red Soils
- Desert Soils
- Laterite Soils
- Mountain Soils
Alluvial soil in India:
- Soil formation:- Alluvial soil is formed due to the deposits of the sediments brought by various rivers.
- Availability:- Alluvial soil is most abundant among different types of soil. highly available across the country. It covers about 40% of the total land in the country. Alluvial soil is widespread in the northern plains, river valleys as well as in deltas and estuaries of various rivers in peninsular India.
- Soil composition:- Alluvial soil is rich in chemicals like Potash, Phosphoric acid, lime and carbon compounds but are deficient in Nitrogen and humus
- Types of Alluvial soil:- There are mainly two types of alluvial soil i.e. Khaddar and Bangar. New alluvium is known as Khadar and old alluvium is known as Bangar.
- Highly fertile:- Alluvial soil is a very fertile type of soil.
- Crops grown:- There are various crops which can be grown in Alluvial Soil like wheat, rice, maize, sugarcane, pulses, oilseed, etc.
- Colour: Alluvial soil is Light Grey in color.
Red soil in India
- Soil formation:- Red soil is formed due to weathering of metamorphic and igneous rocks.
- Soil composition:- It is rich in potash content but lacks phosphate, humus and nitrogen content.
- Availability:- The red soil is found in various regions across the country such as Tamil Nadu, Jharkhand, Odisha, southeast Maharashtra, Madhya Pradesh and some parts of Karnataka. It covers approx 18% of the total land in the country.
- Crops grown:- There are various crops which can be grown in Red Soil like wheat, cotton, pulses, tobacco, oilseeds, potato, etc
- Colour: Red soil is Red in color due to presence of Ferric oxide or Iron content. The lower layer of the red soil is reddish yellow or yellow.
- Soil texture:- The soil's texture varies from being sandy to clay, but it is mainly loamy.
Black soil / Regur soil:
- Soil formation:- Black Soil is made up of volcanic rocks and lava. Black soil is also known as 'regur'.
- Black Cotton Soil :- It is also known as Black Cotton Soil as this type is most suitable for cultivation of cotton.
- Soil composition:- Black Soil is rich in calcium carbonate, potash, lime and magnesium carbonate but has poor phosphorus content.
- Availability:- Black Soil is mostly found in areas such as Gujarat, Madhya Pradesh and Maharashtra. Along with these states, small areas of Black Soil is also found in Tamil Nadu, Andhra Pradesh and Karnataka.
- Soil texture:- Black soil is extremely fine and clayey in nature. It has high water retaining capacity. Due to this nature it develops cracks when dry in rainy season.
- Crops grown:- There are various crops which can be grown in Black Soil like cotton, oilseeds, wheat, linseed, millets, and tobacco.
- Colour: It has deep black to light black color.
Laterite soil in India
- Soil formation:- Laterite soil is formed from the decomposition of rocks and therefore, it contains iron oxide which gives them red or pink colour.
- Soil texture:- Laterite soil becomes soft when wet and hardens when dry.
- Leaching :- It is found in coastal areas where there is alternate dry and wet period (high temperature and high rainfall), in these climatic conditions, leaching of soil takes place in which fertile portion of the soil gets washed away by heavy rains.
- Soil composition :- Laterite soil is rich in Iron and Aluminum deficient in nitrogen, Potash, Lime, etc.
- Availability:- Laterite soil is found in mainly Western and Eastern Ghats, Vindhyas, Malwa plateau and Satpuras. Few other states where Laterite soil can also be found are West Bengal, Andhra Pradesh, Bihar, Meghalaya, Assam, Odisha, etc.
- Crops grown:- There are various crops which can be grown in Laterite Soil like Laterite soil supports crops like Rice, Ragi, Sugarcane, rubber, coconut, tea, coffee and Cashew nuts.
Desert / arid soil
- Soil composition:- These type of soil contains approx 90% of sand and 10% of clay. These are rich in phosphate and deficient in nitrogen, humus and moisture.
- Availability:- Desert soil is found in arid and semi-arid areas such as areas of Rajasthan extending to Rann of Kutch, along with some areas of Haryana and Punjab.
- Vegetation:- Cacti and shrubs are the permanent vegetation which can be seen in the deserts as it is very well adapted to living without moisture for long periods of time
- Color:- The color of desert soil is Red to Brown.
Mountain soil in India
- Soil formation:- Mountain soils are formed due to the accumulation of organic matter which is derived from the forest growth and are generally shallow in depth and immature.
- Soil composition:- Mountain soil is rich in humus but is deficient in lime, potash and phosphorus content. It is normally sandy and has lots of gravels.
- Availability:- Mountain soil is mainly found in Himalayan region, Sikkim, Arunachal Pradesh, Assam, and also in Penninsular India, Eastern Ghats. It covers approx 8% area of Indian subcontinent.
- Soil Texture:- The texture of this type of soil is normally loamy, clayey, alluvial, etc which depends on the mountain region and climate.
- Crops Grown:- There are various crops which can be grown in Mountain Soil like fruits, coffee, tea or spices in states of south India like Kerala, Tamil Nadu and Karnataka.
Few of the important topics related to Geography which would be very helpful for various Government exams are as below:-