Soil Types in India: Characteristics, Distribution and Significance

Soil comes in many types, each with its unique characteristics. From the fertile alluvial soils of the plains to the deep black expanses of the Deccan Plateau, India’s soil diversity is vast and vital for agriculture. Understanding these soils helps us make better decisions for farming and environmental conservation.

Soil Types in India

• Ancient Soil Classification in India: Initially categorized into Urvara (fertile) and Usara (sterile).
• Main Soil Types Identified: Sandy, clayey, silty, loamy, etc.
• Classification Based on Colour: Red, yellow, black, etc.
• Efforts of ICAR: Classified Indian soils based on nature and character, following USDA Soil Taxonomy.
• Classification of Indian Soils: Based on genesis, color, composition, and location as given below,
  1. Alluvial Soils  
  2. Black Soils  
  3. Red Soils  
  4. Laterite Soils 
  5. Forest and Mountain Soils  
  6. Arid and Desert Soils  
  7. Saline and Alkaline Soils  
  8. Peat and Marshy Soils  

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A. Alluvial Soils

• Area: Inland alluvium in Punjab, Haryana, UP, Bihar, West Bengal, Parts of Gujarat and Rajasthan, Deltaic alluvium in deltas of Ganga-Brahmaputra, Mahanadi, Godavari, Krishna and Kaveri, Coastal alluvium along the coastal strips of peninsula.
• Characteristics
  • Kankars: Notably, in the Upper and Middle Ganga plains, two distinct types, Khadar (new alluvium) and Bhangar (older alluvium), are found. Both types bear calcareous concretions known as Kankars.
  • Khadar: is enriched annually by flood deposits.
  • Bhangar: is located away from flood plains. 
  • Loamy: Become more loamy and clayey in the lower and middle Ganga plain and Brahmaputra valley; 
  • Sand Content: reduces from west to east; 
  • Color: Light grey to ash grey depending on deposition depth, material texture, and maturity time; Heavily cultivated due to their fertility; 
  • Mineral Composition: Generally rich in potash and lime but poor in Nitrogen, Humus and Phosphorus. 

B. Black Soil

• Area: Covers around 15%; Predominantly covers the Deccan Plateau that includes parts of Maharashtra, Madhya Pradesh, Gujarat, Andhra Pradesh, and some parts of Tamil Nadu, with significant depth in upper reaches of Godavari and Krishna rivers and north-western Deccan Plateau.
• Characteristics
• Clayey, Deep, and Impermeable Nature: formed due to weathering of fissure volcanic rock; also referred to as ‘Regur Soil’ or ‘Black Cotton Soil’. [UPSC  2021]
• Swelly and Sticky: Swell and become sticky when wet; shrink when dried (develop wide cracks);  
• Self Ploughing: Slow absorption and loss of moisture and good water retention; 
• Colour: Deep black to grey; 
• Mineral Composition: Rich in lime, iron, magnesia, and alumina, with a good content of potash; deficient in phosphorus, nitrogen, and organic matter.

C. Red and Yellow Soil

• Area: Red soil develops on crystalline igneous rocks in the eastern and southern regions of the Deccan Plateau with low rainfall and extends along the piedmont zone of the Western Ghat as red loamy soil. Also present in parts of Odisha, Chattisgarh, and southern areas of the Middle Ganga Plain. 
• Characteristics 
  • While coarse-grained soils found in arid upland regions are usually poor in fertility, fine-grained red and yellow soils are typically fertile; Soil is well drained; 
  • Colour: Reddish colour due to a wide diffusion of iron in crystalline and metamorphic rocks; yellow in hydrated form; 
  • Mineral Composition: Generally deficient in nitrogen, phosphorus, and humus.

D. Laterite Soil

• Area: Higher areas of the Peninsular plateau, notably found in Karnataka, Kerala, Tamil Nadu, Madhya Pradesh, and the hilly regions of Odisha, Ranchi and Assam. 
• Characteristics [UPSC 2013]
  • Develop in areas with high temperatures and high rainfall, resulting in intense leaching; Lime and silica are leached away, and soils rich in iron oxide and aluminium compounds are left behind;
  • Low humus content due to bacterial activity that thrives well in high temperatures; Highly acidic and low water retention;
  • Unsuitable for cultivation, requiring manures and fertilizers to enhance fertility; widely used in brick making; Red laterite soils are favorable for tree crops like cashew nuts in regions of Tamil Nadu, Andhra Pradesh, and Kerala; 
  • Mineral Composition: lacks organic matter, nitrogen, phosphate, and calcium; abundant in iron oxide and potash.

E. Arid Soil

• Area: Mainly found in western Rajasthan
• Characteristics 
  • Kankar Layers: in the lower horizons due to increasing calcium content that restricts water infiltration but ensures soil moisture retention when irrigation is introduced;  Sandy structure and saline nature; Fertility is hindered by the low humus and organic matter content; 
  • Color: red to yellow.
  • Mineral Composition: Lacks moisture, humus and organic matter; insufficient nitrogen and normal phosphate content.

F. Saline Soils

• Area: Arid and semi-arid regions, and waterlogged and swampy areas; more widespread in western Gujarat, deltas of the eastern coast and in Sundarban areas of West Bengal; Southwest Monsoon brings salt particles and deposits there as a crust in the Rann of Kuchchh; Seawater intrusions in the deltas result in formation of saline soils; Fertile alluvial soils are becoming saline in areas of green revolution due to capillary action. Excessive irrigation with dry climatic conditions promotes capillary action leading to salt deposition in the top layer.
• Characteristics
  • Also known as Usara soils; 
  • Structure: ranges from sandy to loamy; 
  • Gypsum is added as a remedial measure against soil salinity; 
  • Mineral Composition: Deficient in nitrogen and calcium; high proportion of sodium, potassium, and magnesium is present. 

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G. Peaty Soils

• Area: Prominently found in regions with heavy rainfall and high humidity with good vegetation growth; widely distributed in northern Bihar and southern Uttarakhand, along with coastal stretches of West Bengal, Odisha, and Tamil Nadu.  
• Characteristics 
  • Heavy, Black in colour: and, in many places, exhibit alkaline properties
  • Large quantities of dead organic matter with high humus and organic content. 
  • Organic Matter: may go up to 40-50 percent.

H. Forest Soils

• Area: Forest areas with sufficient rainfall; found in Himalayan region, Western and Eastern Ghats as well as in some parts of the Peninsular plateau.
• Characteristics 
  • Loamy and silty on valley sides and coarse-grained on upper slopes; 
  • Structure and Texture: vary depending on the mountain environment; Particularly in the snow-clad regions of the Himalayas, 
  • Denudation: these soils undergo denudation, becoming acidic with a low humus content; soils in the lower valleys are fertile.

Conclusion

India’s soil diversity plays a crucial role in agriculture and ecosystem health. Protecting and managing these soils is essential for sustainable farming and preserving the environment. By appreciating the unique characteristics of each soil type, we can work towards a greener and more productive future.

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