Types of Soil in India: Features, Characteristics, and Geographical Distribution

Soil is the top layer of the earth's surface that is formed from weathering of rocks, decay of organic materials and biological activity over thousands of years. Soil is the foundational natural resource for India. This is because India is predominantly an agricultural-based economy and it generates around 18% of GDP in agriculture and almost 60% of the population in the country is engaged in agriculture.

According to Indian Council of Agricultural Research (ICAR) the soils of India have been divided into eight major types based on genesis, colour, composition and location. This classification is done by the National Bureau of Soil Survey and Land Use Planning (NBSS & LUP).

Here are the types of soil in India: 

1. Alluvial Soil

2. Black Soil (Regur)

3. Red and Yellow Soil

4. Laterite Soil

5. Arid and Desert Soil

6. Forest and Mountain Soil

7. Saline and Alkaline Soil

8. Peaty and Marshy Soil

In ancient India soils were just divided into Urvara (fertile) or Usara (sterile) terms that are still used in the rural areas today.

Quick Overview

1. Alluvial Soil

Total Area Covered: The total area covered is about 15 lakh sq. km which is approximately 43 to 46% of the total geographical area of India. This is by far, the largest soil group in the country.

Formation: Alluvial soils are transported and deposited soils which are formed when the sediments (sand, silt, clay) are transported and deposited by rivers originating from Himalayas and Peninsular plateau.

Physical Properties:

• Texture: Differs as per region. For example, there are sandy loams in western Punjab and Haryana whereas fine silt and clay cover the lower Ganga plain and Brahmaputra valley. 

• Structure: This soil is quite porous due to loamy nature and has good drainage and conditions favourable for agriculture

• It is constantly replenished by recurrent floods 

• Immature soil with weak profile due to recent origin

Chemical Properties:

• This soil is rich in: Potash, phosphoric acid, lime

• Deficient in: Nitrogen and organic humus (this drives heavy urea consumption across the Indo-Gangetic belt)

• Proportion of iron oxide and lime varies within a wide range across regions

• pH: 7.0 to 8.5 (neutral to slightly alkaline)

Geographical Distribution: Indo-Gangetic-Brahmaputra Plain (Punjab, Haryana, Uttar Pradesh, Bihar and West Bengal), eastern coastal deltas (Krishna-Godavari, Mahanadi, Cauvery), river valley areas in the Peninsular India, Narmada valley and Tapi valley, northern Gujarat.

Crops Supported: Wheat, rice, sugarcane, jute, pulses, oilseeds, cotton, vegetables. This soil is very responsive to irrigation and fertilizers. 

 2. Black Soil (Regur / Black Cotton Soil)

Total Area Covered: It covers 5.46 lakh sq. km which is about 16.6% of India's total geographical area.

Formation: Black soil is a soil formed by the weathering of Deccan Trap volcanic rocks.

This soil is also known as the Regur soil. The word Regur is derived from the Telugu word Regada. It usually forms at places where annual rainfall is between 50 and 80 cm and the rainy days between 30 and 50 days.

Physical Properties:

• Colour: Deep black to light black, due to titaniferous magnetite (iron and aluminium compounds in basalt)

• Texture: High clay content which is over 62%. also contains about 10% alumina and 9 to 10% iron oxide

• Self-ploughing characteristic: Widely cracks in drought (cracks are several centimetres deep) and it swells and gets highly sticky when wet. This type of churning also involves mixing surface material with deeper material, which means that no external ploughing is required.

• It has very high water-retention capacity and difficult to work during the rainy season

Chemical Properties:

• Rich in: Iron oxides, lime (calcium), magnesium carbonates, potassium, aluminium

• Deficient in: Phosphorus, nitrogen, organic matter

Geographical Distribution: Deccan Plateau covering Maharashtra, Madhya Pradesh, Gujarat, Karnataka, Andhra Pradesh, Chhattisgarh, Tamil Nadu (Coimbatore plateau), Rajasthan, and Jharkhand up to Rajmahal Hills. Also present on the Malwa Plateau.

Crops Supported: Cotton (primary crop, hence the name Black Cotton Soil), soybean, wheat, jowar, linseed, castor, sunflower, and millets.

3. Red and Yellow Soil

Total Area Covered: About 10.6% of the geographical area in India with about 3.5 lakh sq. km area coverage. This is considered as the second most important soil group based on some definitions and classifications. 

Formation: It has formed as a result of the weathering of some crystalline igneous and metamorphic rocks (granites, gneisses, schists) in an environment of low rainfall and good drainage in the region of Deccan plateau.

Physical Properties:

• Colour: Diffusion of iron oxides through the soil gives it a red colour. It turns yellow when moist and is, therefore, known as “red and yellow soil.”

• Texture: The texture of this soil varies from sand to clay and loam. It is generally porous and crumbly. 

• Depth: It is quite thin, poor, gravelly, and stony on uplands. However in valleys and lower plains it is fine-grained and relatively fertile. 

Chemical Properties:

• Rich in: Iron, and potassium

• pH levels range from 6.0 to 7.0 

Geographical Distribution: Eastern and southern Deccan Plateau covering Tamil Nadu (almost entirely), Karnataka, Andhra Pradesh, parts of Odisha, Chhattisgarh, and Jharkhand (Chota Nagpur Plateau).

Crops Supported: Millets (jowar, bajra), pulses, groundnut, tobacco, potatoes.

4. Laterite Soil

Total Area Covered: 2.48 lakh sq. km or about 4.3% of the total geographical area of India.

Formation: Laterite soils are found in tropical and sub-tropical regions with wet and dry altering seasons. 

Intense leaching by heavy rain and high temperatures from soluble constituents (silica, lime, potash) leave a residue rich in iron and aluminium oxides. When exposed to air it hardens and takes a brick like appearance.

Physical Properties:

• Colour: Brick-red to reddish-brown (due to iron oxides)

• Texture: Highly porous.

• Hardens on exposure to air and it is widely used as building material in Kerala and Karnataka

• Prone to erosion and degradation, especially on slopes

Chemical Properties:

• Rich in: Iron oxides, aluminium oxides,

• pH: 4.5 to 6.5 (strongly acidic)

• They are very poor in lime, magnesia, potash and nitrogen.

• In wet places, the soil might have higher humus

Geographical Distribution: Western Ghats summits (Maharashtra, Karnataka, Kerala), Eastern Ghats and associated regions (Odisha), Andhra Pradesh, parts of Madhya Pradesh, West Bengal, Meghalaya, Assam, and Jharkhand.

Crops Supported: Plantation crops including tea (Karnataka, Kerala), coffee, rubber. Similarly it supports cashew nuts in Tamil Nadu, Andhra Pradesh and Kerala.

5. Arid and Desert Soil

Total Area Covered: It covers around 1.42 lakh sq. km which is approximately 4.32% of India's total geographical area.

Formation: These soils are formed from wind activity in dry and semi dry environments. They have formed on the breakdown of neighbouring rock and material from the blown up Indus basin and the coast. Humus doesn't form in high temperatures and during rapid evaporation.

Physical Properties:

• The colour of this soil ranges from red to brown

• The texture is sandy and has gravel

• It is quite low in moisture 

• It has extreme daily thermal fluctuations that is why it lacks vegetation

• Annual rainfall in these regions is below 40 cm

Chemical Properties:

• It has a high concentration of gypsum, and sodium. 

• Ii is also rich in calcium carbonate, which restricts water infiltration

• Deficient in organic matter and humus. 

Geographical Distribution: Western Rajasthan (Thar Desert), west of the Aravallis, northern Gujarat, Kutch (Rann of Kutch), western parts of Haryana, and south-western parts of Punjab. 

Crops Supported: Bajra, jowar, drought-resistant pulses (green-gram, black-gram)

6. Forest and Mountain Soil

Total Area Covered: It covers approximately 7.94% of India's total geographical area.

Formation: Forest soils are formed through the addition of organic materials from forest growth. They are typically shallow and immature, and change in character rapidly with respect to altitude.

Physical Properties:

• This soil has loamy and silt based texture in valleys which changes to coarse and gravelly on steep slopes.

• It has high porosity 

• It has excellent water retention

• Stable and cooler soil temperatures due to forests and mountain altitudes. 

Chemical Properties:

• Highly acidic with pH levels of 4.5–5.5. 

• It is quite rich in humus and organic matter

• It has a high quantity of nitrogen. 

• The soil lacks phosphorus and potassium

Geographical Distribution: Himalayan region (Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Sikkim, Arunachal Pradesh), Assam hills, Meghalaya, Nagaland, Mizoram, Western Ghats, Eastern Ghats, and parts of Andaman and Nicobar Islands. 

Crops Supported: Tea, coffee, spices, tropical fruits, apples and potatoes in temperate zones.

7. Saline and Alkaline Soil

Area Coverage: It is approximately spread in 1.29% of India's total geographical area.

Formation: These soils develop in arid and semi-arid regions due to capillary rise which means high evaporation and low rainfall. The groundwater has natural salts and when it evaporates, the soil leaves salts behind to form a surface. 

Physical Properties: 

• It has a sandy and loamy texture.  

• Restricts water infiltration 

• Restricts growth root

Chemical Properties:

• pH: Above 8.5 (alkaline)

• Often have a hard calcareous layer. 

• Saline soils contain large portions of sodium, potassium, and magnesium, making them largely infertile

Geographical Distribution: Arid and semi-arid regions of Punjab, Haryana, and Rajasthan. Similarly it is found in western coast of Gujarat including the Rann of Kutch where monsoon winds deposit high salt particles as a crust. 

Crops Supported: Sorghum, Barley and Cotton

8. Peaty and Marshy Soil

Total Area Covered: It covers approximately 2.17% of India's total geographical area.

Formation: Peaty soils are formed in areas that have high humidity and heavy rainfall where large quantities of dead organic matter collects. This results in high organic content and rich humus. 

Physical Properties

• The texture is very heavy and clay-like 

• The soil has high porosity due to high organic matter content

• They have high water retention capacity. 

• It is majorly used for paddy cultivation

Chemical Properties:

• It is very rich in organic matter and humus

• It is highly acidic with pH levels ranging from 3.0 to 5.5

• They lack micronutrients like copper and manganese.

Geographical Distribution: Kerala backwaters (Kuttanad region), parts of northeastern India (Assam, West Bengal), Sundarbans, coastal Odisha, Uttarakhand (Almora, Nainital districts), and Bihar.

Crops Supported: Rice, jute, rubber, coconut, spices, aquatic and wetland crops.