NCERT Class 11 Indian Geography Chapter 6 – Soils

NCERT Class 11 Indian Geography Chapter 6 explains the formation, classification and distribution of soils in India. In NCERT Class 11 Indian Geography Chapter 6, students study major soil types such as alluvial, black, red, laterite, arid and forest soils along with soil erosion and conservation methods.

NCERT Class 11 Indian Geography Chapter 6 is highly important for CBSE board exams and competitive exams like UPSC and BPSC because questions related to soil types, fertility and land degradation are frequently asked. A clear understanding of NCERT Class 11 Indian Geography Chapter 6 helps in linking agriculture, climate and environmental sustainability. Students should refer to the official NCERT website at for authentic textbooks and syllabus updates.

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1. Introduction

• Soil is the uppermost layer of the earth’s crust, formed by the mixture of rock debris and organic matter, and it supports plant growth and human life.
• It develops over thousands of years through processes of weathering and gradation acting upon the parent rock (bedrock).
• The major factors influencing soil formation are relief, parent material, climate, vegetation, other life-forms and time, along with human activities.
• Soil consists of four main components: mineral particles, humus, water and air, and their proportion varies according to soil type.
• When a pit is dug, soil shows distinct layers called horizons, forming a soil profile.
• Horizon A (Topsoil) contains organic matter mixed with minerals and nutrients essential for plant growth.
• Horizon B (Subsoil) is a transition zone with mineral matter and some organic content.
• Horizon C consists of loose parent material, which gradually develops into upper soil layers.

2. Classification of soils

• India has a great variety of soils due to differences in relief features, landforms, climate and vegetation across regions.
• In ancient times, soils were classified into Urvara (fertile) and Usara (sterile) based on productivity.
• In the 16th century, soils were classified based on texture, colour, slope and moisture content, such as sandy, clayey, silty and loam soils.
• After Independence, scientific soil surveys were conducted by agencies like the Soil Survey of India (established in 1956) and the National Bureau of Soil Survey and Land Use Planning (under ICAR).
• The Indian Council of Agricultural Research (ICAR) classified Indian soils according to the USDA Soil Taxonomy, including orders like Inceptisols (39.74%), Entisols (28.08%), Alfisols (13.55%), Vertisols (8.52%), Aridisols (4.28%), Ultisols (2.51%), Mollisols (0.40%) and Others (2.92%).
• On the basis of genesis, colour, composition and location, Indian soils are grouped into eight major types.
• These eight major soil types are: Alluvial, Black, Red and Yellow, Laterite, Arid, Saline, Peaty and Forest Soils.
• This scientific classification helps in understanding soil properties for agriculture, conservation and land-use planning.

2.1 Alluvial Soils

• Alluvial Soils are the most widespread soils in India, covering about 40% of the total geographical area, mainly in the Northern Plains and river valleys.
• They are depositional soils, formed by the transportation and deposition of sediments by rivers such as the Ganga, Brahmaputra and Indus and their tributaries.
• These soils extend through a narrow corridor in Rajasthan into the plains of Gujarat, and are also found in the east coast deltas of rivers like Mahanadi, Godavari, Krishna and Kaveri.
• The texture varies from sandy loam to clay, and they are generally rich in potash but poor in phosphorus.
• In the Upper and Middle Ganga Plain, two types occur: Khadar (new alluvium) deposited annually by floods, and Bhangar (old alluvium) found above flood levels.
• Both Khadar and Bhangar soils contain calcareous concretions called ‘Kankars’, especially in older deposits.
• The colour ranges from light grey to ash grey, depending on depth and maturity of deposition.
• These soils are highly fertile and intensively cultivated for crops like wheat, rice, sugarcane and pulses.

2.2 Black Soil

• Black Soil, also known as Regur Soil or Black Cotton Soil, covers large parts of the Deccan Plateau, including Maharashtra, Madhya Pradesh, Gujarat, Andhra Pradesh and parts of Tamil Nadu.
• It is especially deep in the upper reaches of the Godavari and Krishna rivers and in the northwestern Deccan Plateau.
• These soils are clayey, deep and impermeable, and they swell when wet and shrink on drying, developing wide cracks — a process called “self-ploughing”.
• Due to slow absorption and loss of moisture, black soil retains water for a long time, making it suitable for rain-fed crops.
• Chemically, black soils are rich in lime, iron, magnesia, alumina and potash, but deficient in nitrogen, phosphorus and organic matter.
• The colour varies from deep black to grey, depending on composition and location.
• These soils are particularly suitable for the cultivation of cotton, along with crops like soybean, sugarcane and groundnut.
• The high clay content makes the soil difficult to plough during wet conditions but very productive under proper management.

2.3 Red and Yellow Soil

• Red and Yellow Soils develop on crystalline igneous and metamorphic rocks in areas of low rainfall, mainly in the eastern and southern parts of the Deccan Plateau.
• These soils are widely found in Tamil Nadu, Karnataka, Andhra Pradesh, Telangana, Odisha, Chhattisgarh, and parts of the southern Middle Ganga Plain.
• A long stretch of red loamy soil occurs along the piedmont zone of the Western Ghats.
• The reddish colour is due to the presence and diffusion of iron oxide, and the soil appears yellow when iron is present in a hydrated form.
• The fine-grained red and yellow soils are relatively fertile, while coarse-grained soils in dry upland areas are less fertile.
• These soils are generally poor in nitrogen, phosphorus and humus, requiring fertilisers for better productivity.
• Texture varies from sandy to loamy, depending on location and parent material.
• Crops grown on these soils include millets, pulses, groundnut and cotton, depending on rainfall and irrigation availability.

2.4 Laterite Soil

• Laterite Soil derives its name from the Latin word “Later” meaning brick, as it becomes hard like brick on exposure.
• It develops in regions of high temperature and heavy rainfall, mainly due to intense leaching under tropical climatic conditions.
• During heavy rainfall, lime and silica are leached away, leaving behind soils rich in iron oxide and aluminium compounds.
• These soils are generally poor in organic matter, nitrogen, phosphate and calcium, but relatively rich in iron and potash.
• Laterite soils are widely found in the higher areas of the Peninsular Plateau, especially in Karnataka, Kerala, Tamil Nadu, Madhya Pradesh, and the hilly areas of Odisha and Assam.
• In Tamil Nadu, Andhra Pradesh and Kerala, red laterite soils are suitable for plantation crops like cashewnut.
• With proper application of manures and fertilisers, these soils can support cultivation of crops such as tea, coffee and rubber.
• Laterite soil is commonly cut into blocks and used as building material in many parts of South India.

2.5 Arid Soils

• Arid Soils are found in regions with low rainfall and high temperature, mainly in Western Rajasthan, exhibiting typical arid topography.
• These soils range in colour from red to brown and are generally sandy in texture and saline in nature.
• Due to dry climate and high evaporation, they lack moisture and humus, making them poor in fertility.
• Nitrogen content is low, while phosphate content is normal, and organic matter is very limited.
• The lower horizons contain ‘Kankar’ (calcareous nodules) due to increasing calcium content downward, which restricts water infiltration.
• In some areas, the salt content is so high that common salt is extracted by evaporating saline water.
• With irrigation facilities, these soils can support crops, as moisture becomes available for plant growth.
• Arid soils require careful management to prevent further degradation and desertification.

2.6 Saline Soils

• Saline Soils, also known as Usara Soils, contain high proportions of sodium, potassium and magnesium salts, making them infertile and unsuitable for most crops.
• These soils develop in regions with dry climate and poor drainage, where salts accumulate on the surface due to high evaporation.
• They occur mainly in western Gujarat, the Rann of Kachchh, deltas of the eastern coast, and in the Sunderban region of West Bengal.
• In the Rann of Kachchh, salt particles are deposited as a crust due to the action of the Southwest Monsoon winds.
• In deltaic regions, seawater intrusion contributes to salinity in the soil.
• In irrigated areas, especially in Punjab and Haryana, excessive irrigation and poor drainage lead to capillary action, which brings salts to the surface.
• Saline soils are deficient in nitrogen and calcium, affecting crop productivity.
• To reclaim saline soils, farmers are advised to apply gypsum and improve drainage conditions.

2.7 Peaty Soils

• Peaty Soils develop in areas of heavy rainfall and high humidity, where dense vegetation growth leads to accumulation of organic matter.
• Large quantities of dead plant material decompose slowly under waterlogged conditions, resulting in very high humus content (up to 40–50%).
• These soils are generally dark black in colour, heavy in texture and rich in organic matter.
• In many places, peaty soils are alkaline in nature, affecting their agricultural suitability.
• They are commonly found in the northern part of Bihar, southern Uttarakhand, and coastal areas of West Bengal, Odisha and Tamil Nadu.
• Due to high organic content, these soils are suitable for certain crops if properly drained and managed.
• Poor drainage and waterlogging are common problems associated with peaty soils.
• Their high moisture-retaining capacity makes them distinct from other soil types in India.

2.8 Forest Soils

• Forest Soils are formed in regions of adequate rainfall and forest cover, mainly in the Himalayan region and hilly areas.
• The texture and structure of these soils vary with altitude and mountain environment, showing differences between slopes and valleys.
• On the valley sides, soils are generally loamy and silty, while on the upper slopes, they are coarse-grained and less developed.
• In the snow-bound areas of the Himalayas, these soils undergo denudation and are often acidic with low humus content.
• In lower valleys, forest soils are relatively more fertile due to accumulation of organic matter.
• The composition depends on the type of forest vegetation and climatic conditions of the region.
• These soils support dense forest growth and play a crucial role in watershed protection and ecological stability.
• Proper forest management is essential to prevent erosion and maintain soil fertility in mountainous regions.

3. Soil degradation

• Soil Degradation refers to the decline in soil fertility and reduction in soil depth due to erosion, misuse and improper land management.
• It leads to depletion of essential nutrients and reduces the productive capacity of land.
• The degree of degradation varies according to topography, rainfall intensity and wind velocity.
• Excessive use of chemical fertilisers without adding organic manure reduces humus content and hardens the soil over time.
• In irrigated areas, especially in the Green Revolution regions of Punjab and Haryana, over-irrigation has led to salinity and waterlogging.
• Large areas of India are affected by soil degradation due to deforestation, overgrazing, mining and shifting cultivation.
• According to estimates, about half of India’s total land area is under some degree of degradation.
• Soil degradation adversely affects agricultural productivity, water retention capacity and ecological balance.

4. Soil erosion

• Soil Erosion refers to the removal of the top fertile layer of soil by natural agents like water and wind.
• Normally, there is a balance between soil formation and erosion, but this balance is disturbed due to human activities such as deforestation, overgrazing and improper farming.
• Water erosion is more serious in India and occurs mainly in the form of sheet erosion and gully erosion.
• Sheet erosion takes place on level lands after heavy rainfall, removing the fine and fertile topsoil gradually and often unnoticed.
• Gully erosion occurs on steep slopes, forming deep channels; areas with extensive gullies are called badlands, such as in the Chambal Basin, and parts of Tamil Nadu and West Bengal.
• India loses about 8,000 hectares of land every year to ravines formed by gully erosion.
• Wind erosion is common in arid and semi-arid regions, particularly in Western Rajasthan, where loose sand is blown away.
• Eroded soil carried into rivers reduces their carrying capacity, causing frequent floods and damage to agricultural lands.

5. Soil Conservation

• Soil Conservation refers to methods adopted to prevent soil erosion, degradation and exhaustion, and to maintain long-term soil fertility.
• Lands with a slope gradient of 15–25% should not be used for cultivation; if used, terrace farming should be practiced to reduce runoff.
• Contour bunding and contour terracing help slow down water flow on slopes and reduce soil loss.
• Check dams and gully plugging are used to control gully erosion, especially in ravine-prone areas like the Chambal Basin.
• In arid and semi-arid regions, development of shelter belts and agro-forestry helps prevent encroachment of sand dunes, especially in Western Rajasthan.
• Controlled grazing, regulated forestry, crop rotation, mixed farming and cover cropping help maintain soil fertility and prevent erosion.
• Experiments to stabilise sand dunes have been conducted by the Central Arid Zone Research Institute (CAZRI) in Rajasthan.
• The Central Soil Conservation Board (Government of India) prepares conservation plans based on climate, land configuration and social conditions, emphasising integrated land-use planning.

NCERT Class 11 Indian Geography Chapter 6 provides a comprehensive understanding of soil types, their characteristics and conservation strategies in India. Mastering NCERT Class 11 Indian Geography Chapter 6 helps students confidently answer conceptual and map-based questions in CBSE and competitive exams.

A strong grasp of NCERT Class 11 Indian Geography Chapter 6 also prepares students to understand natural hazards and environmental challenges discussed in the next chapter.

Continue reading NCERT Class 11 Indian Geography Chapter 7 – Natural Hazards and Disasters to understand disaster types and management strategies in India.

Frequently Asked Questions (FAQs)

Q1. What is NCERT Class 11 Indian Geography Chapter 6 about?
NCERT Class 11 Indian Geography Chapter 6 explains soil formation, classification of soils and soil conservation in India.

Q2. Why is NCERT Class 11 Indian Geography Chapter 6 important for exams?
NCERT Class 11 Indian Geography Chapter 6 is important because questions on soil types, soil erosion and fertility are frequently asked in CBSE and competitive exams.

Q3. Which soil types are covered in NCERT Class 11 Indian Geography Chapter 6?
The chapter covers alluvial, black, red and yellow, laterite, arid, saline, peaty and forest soils.

Q4. How does NCERT Class 11 Indian Geography Chapter 6 help in UPSC preparation?
NCERT Class 11 Indian Geography Chapter 6 builds conceptual clarity about soil resources and land degradation, which is important for geography and environment sections in UPSC and BPSC exams.

Q5. Which chapter should be studied after NCERT Class 11 Indian Geography Chapter 6?
Students should continue with NCERT Class 11 Indian Geography Chapter 7 – Natural Hazards and Disasters.

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