Soils are not the same everywhere. It was recognized back from earlier times about the characteristics of different types of soils, and modern classification has been made a few centuries back.

In India, the Indian Council of Agricultural Research (ICAR) has analyzed soils and classified them into eight different types.

1. Alluvial Soil,
2. Black Cotton Soil,
3. Red Soil,
4. Laterite Soil,
5. Mountain or Forest Soils,
6. Arid or Desert Soil,
7. Saline and Alkaline Soil,
8. Peaty, and Marshy Soil

Classification of Soils in India

In prehistoric times, soils used to be categorized into two central groups – Urvara and Usara, which were fertile and sterile. These terms are still used in some rural areas.

In the 16th century A.D, Soils were classified based on their intrinsic characteristics and visible features. Based on texture, main soil types were distinguished as sand, clay, silt, loam, etc. Based on colour, they were red, yellow, black, etc.

The Soil Survey of India was instituted in 1956 which became the institute to maintain the health of soils in India.

Based on colour, composition, and location, the soils of India have been generally classified into the following.

• Alluvial soils
• Black soils
• Red and Yellow soils
• Laterite soils
• Arid soils
• Saline soils
• Peaty and Marshy soils
• Forest soils

Types of Soils in India: Alluvial Soil

• Alluvial soils are extensive in the northern plains and the river channels.
• These soils embrace about 40 percent of the entire area of the nation.
• They are depositional soils, carried and placed by rivers and streams.
• Through a linear passage in Rajasthan, they stretch toward the lowlands of Gujarat.
• In the Peninsular region, they are found in deltas of the east coast and the river valleys.
• The alluvial soils differ in essence from sandy loam to clay.
• They are usually worthy in potash but lower in phosphorus.
• In the Higher and Middle Ganga plain, two contrasting models of alluvial soils have developed, viz. Khadar and Bhangar.

• Khadar is the modern alluvium and is deposited by floods annually, which enriches the soil by depositing fine silts.
• Bhangar depicts a method of more traditional alluvium, dropped away from the flood plains.
• These soils are extra loamy and clayey in the lower and central Ganga plain and the Brahmaputra channel.
• The sand content decreases from the west to the east.
• The tone of the alluvial soils ranges from light grey to ash grey.
• Alluvial soils are intensively cultivated across India.

Types of Soils in India: Black Soil

• Black soil comprises most of the Deccan Plateau which incorporate parts of Maharashtra, Madhya Pradesh, Gujarat, Andhra Pradesh, and some parts of Tamil Nadu.
• In the upper extensions of the Godavari and the Krishna, the black soil is very deep.
• These soils are also recognized as the ‘Regur Soil’ or the ‘Black Cotton Soil’.
• Black soils are usually clayey and deep.

• Because of the character of late intake and lack of moisture, the black soil retains the moisture for a very long time, which benefits the crops, especially the rain-fed ones, to maintain even during the dry period.
• Chemically, the black soils are abundant in lime, iron, magnesia, and alumina.
• The richness of the soil extends from deep black to grey.

Types of Soils in India: Red and Yellow Soil

• Red soil emerges on crystalline igneous rocks in regions of moderate rainfall in the easterly and southerly sections of the Deccan Plateau.
• Yellow and red soils are also observed in some sectors of Odisha and Chattisgarh and the southern parts of the central Ganga plain.
• They are generally inadequate in nitrogen, phosphorus, and humus.

Types of Soils in India: Laterite Soil

• The laterite soils develop in areas with high temperatures and high rainfall.
• Humus content of the soil is removed fast by bacteria that thrive well in high temperatures.
• These soils are deficient in organic matter, nitrogen, phosphate, and calcium, while iron oxide and potash are in surplus amounts. Hence, laterites are not proper for cultivation.
• Red laterite soils in Tamil Nadu, Andhra Pradesh, and Kerala are more fitting for tree crops like cashew nuts.
• Laterite soils are extensively cut as bricks for usage in house development.
• These soils have principally evolved in the higher regions of the Peninsular plateau.
• The laterite soils are generally found in Karnataka, Kerala, Tamil Nadu, Madhya Pradesh, and the mountainous stretches of Odisha and Assam.

Types of Soils in India: Arid Soil

• Arid soils vary from red to brown in color.
• They are commonly sandy in composition and saline in nature.
• Nitrogen is lacking and the phosphate content is average.
• Lower horizons of the soil are filled by ‘kankar’ bands because of the growing calcium content downwards.

• The ‘Kankar’ layer formation in the bottom horizons restricts the infiltration of water, and as such when irrigation is made available, the soil moisture is readily available for sustainable plant growth.
• Arid soils are characteristically developed in western Rajasthan, which exhibits characteristic arid topography.

Types of Soils in India: Saline Soil

• They are also recognized as Usara soils.
• Saline soils hold a greater symmetry of sodium, potassium, and magnesium and do not hold any vegetative maturity.
• They occur in arid and semi-arid areas and waterlogged and swampy regions.
• They lack nitrogen and calcium.
• Saline soils are further extended in western Gujarat, deltas of the eastern coast, and in the Sundarban region of West Bengal.
• In the areas of intensive cultivation with excessive use of irrigation, especially in areas of the green revolution, the fertile alluvial soils are becoming saline.
• Extreme irrigation with dry climatic conditions supports capillary action, which follows in the deposition of salt on the topmost layer of the soil.
• In such measures, particularly in Punjab and Haryana, farmers are recommended to add gypsum to resolve the obstacle of salinity in the soil.

Types of Soils in India: Peaty Soil

• Peaty Soils are seen in areas of abundant rainfall and unusual humidity, where there is a healthy growth of vegetation.
• Thus, a large quantity of dead organic matter accumulates in these areas, and this gives rich humus and organic content to the soil.
• Organic matter in these soils may stretch up to 40-50 per cent.
• These soils are commonly heavy and black in colour. In various places, they are salty also.
• They are found extensively in the northern part of Bihar, the southern part of Uttaranchal, and the waterfront areas of West Bengal, Orissa, and Tamil Nadu.

Types of Soils in India: Forest Soil

• Forest soils are developed in forest areas where ample rainfall is available.
• They are loamy and silty on valley sides and grainy on the higher inclines.
• In the snow-isolated areas of the Himalayas, they encounter denudation and are acidic with low humus content.
• The soils observed in the lower valleys are rich.

FAQs

Q1: How is soil classified in India?

Q2: What is the most widespread type of soil in India?

Q3: What are the key features of black soil?

Q4: What is the significance of red soil in India?

Q5: How does laterite soil form, and where is it found in India?

MCQs

1. Which type of soil is best suited for cotton cultivation?

a) Alluvial soil

b) Black soil

c) Red soil

d) Laterite soil

2. Alluvial soil is predominantly found in which region of India?

a) Deccan plateau

b) Western Ghats

c) Indo-Gangetic plains

d) Himalayan region

3. Which of the following soils is characterized by high iron oxide content, giving it a reddish color?

a) Black soil

b) Alluvial soil

c) Red soil

d) Laterite soil

4. Laterite soil is commonly found in which regions of India?

a) Indo-Gangetic plains

b) Western Ghats and Eastern Ghats

c) Northern plains

d) Thar desert

5. Which type of soil is known for its poor fertility but can be made productive with irrigation and fertilization?

a) Black soil

b) Alluvial soil

c) Red soil

d) Arid soil

GS Mains Questions and Model Answers

Q1: Discuss the significance of alluvial soil for Indian agriculture and its contribution to the economy.

Answer: Alluvial soil is one of the most fertile soils in India and plays a crucial role in the country's agriculture. It is found extensively in the Indo-Gangetic plains and coastal regions, covering about 43% of the total land area. Alluvial soil is rich in minerals like potash, phosphoric acid, and lime, making it highly productive for growing a variety of crops, including rice, wheat, sugarcane, pulses, and vegetables. This soil’s fertility and ease of cultivation have contributed to India’s Green Revolution, which transformed the country’s agricultural productivity. The alluvial plains are also home to intensive irrigation systems, further boosting agricultural output. The significance of alluvial soil lies not only in its agricultural productivity but also in its contribution to India’s food security and rural economy. The crops grown on alluvial soil are key to both domestic consumption and export, making it an essential resource for India’s economic growth.

Q2: Analyze the formation of black soil and its importance in cotton cultivation in India.

Answer: Black soil, also known as regur soil, is formed through the weathering of volcanic rocks and is mainly found in the Deccan plateau, including regions of Maharashtra, Madhya Pradesh, Gujarat, Andhra Pradesh, and Karnataka. This soil is known for its moisture-retaining properties and is rich in important nutrients like calcium carbonate, magnesium, potash, and lime. The high clay content allows black soil to retain moisture for a long time, even during dry seasons, which makes it ideal for dry farming. Black soil is particularly suited for cotton cultivation, earning it the name "cotton soil." India is one of the largest producers of cotton, and the availability of black soil in regions like Maharashtra and Gujarat has been instrumental in this achievement. Black soil’s ability to sustain crops like cotton, along with cereals and oilseeds, makes it a vital component of India’s agricultural landscape.

Q3: Evaluate the challenges and opportunities of cultivating crops on red soil in India.

Answer: Red soil, predominantly found in Tamil Nadu, Karnataka, Andhra Pradesh, and Odisha, poses both challenges and opportunities for agriculture. The major challenge with red soil is its low fertility due to the lack of essential nutrients like nitrogen, phosphorus, and humus. The soil is also less capable of retaining moisture, making it unsuitable for water-intensive crops without proper irrigation. However, red soil offers several opportunities when properly managed. With the application of fertilizers and irrigation techniques, red soil can be used to cultivate crops such as millets, pulses, groundnuts, and cotton. The widespread availability of red soil in semi-arid regions also provides an opportunity for dryland farming practices. Additionally, red soil is often found in areas with good sunlight exposure, which is favorable for crop growth. Thus, while red soil presents certain challenges, its agricultural potential can be harnessed with the right farming techniques and support systems.

Previous Year Questions on  classification of soil in india

1. UPSC CSE 2017

Question: Discuss the characteristics and agricultural importance of alluvial soil in India. 

Answer: Alluvial soil is one of the most important and fertile soils found in India, covering vast areas of the Indo-Gangetic plains, parts of the coastal regions, and the deltas of major rivers. The soil is formed by the deposition of sediments brought down by rivers, making it rich in minerals like potash, lime, and phosphoric acid, which are vital for agricultural productivity. The fine-grained texture of alluvial soil allows for easy cultivation, and its fertility supports a wide range of crops, including staples like rice, wheat, and sugarcane. The alluvial plains are also highly irrigated, further enhancing crop yields. The availability of this fertile soil has contributed significantly to India’s agricultural output, making the Indo-Gangetic plains the country's primary agricultural region. The soil's natural fertility, coupled with intensive farming practices, has made it crucial for ensuring food security and supporting the livelihoods of millions of farmers across India.

2. UPSC CSE 2018

Question: Analyze the suitability of black soil for cotton cultivation and its distribution in India. 

Answer: Black soil, also known as regur soil, is highly suited for cotton cultivation due to its moisture-retaining capacity and rich mineral content. Found predominantly in the Deccan plateau region, including Maharashtra, Madhya Pradesh, Gujarat, Andhra Pradesh, and Karnataka, black soil is formed from the weathering of volcanic rocks. The soil’s high clay content allows it to retain moisture for extended periods, even during dry spells, making it ideal for dryland farming and crops like cotton. In addition to cotton, black soil is also suitable for growing cereals, oilseeds, and legumes. The natural fertility of black soil has contributed to India’s status as one of the largest cotton producers in the world. The distribution of black soil in the Deccan plateau has supported the growth of a robust cotton-based textile industry, further enhancing its agricultural and economic significance.