Introduction

Soils

• The layer at the top of earth’s crust with a thin structure formed from the disintegration of rocks due to the actions of wind, water, and glaciers is called Soil. It includes rock particles made of organic content
• Soil study in their regular situation is Pedology. The process by which soil is formed from multiple phenomena such as weathering, leaching, calcification is known as Pedogenesis
• Factors like climatic conditions, surface relief, natural vegetation, and rock material are associated with the formation of soil in India

Soil Profile

• The soil profile is the vertical section of soil with different layers in it. The layers vary in colour, depth, chemical composition as well as texture. The layers are identified to be Soil Horizon
• It is the layer lying equivalent to the surface of the soil with variance among other layers
• Physical features such as color and texture define each Horizon
• The layer at the topmost part of the Horizon is usually rich in humus, minerals, and is dark in color. The major role of humus is to provide nutrients to the plant growing in the soil and increase its fertility. The layer is termed as A-Horizon also termed as the Topsoil, which is soft, porous, and possesses the capability of retaining more water
• The layer that follows has a lesser amount of humus as compared to the above layer. Minerals are produced to a suitably huge extent. This layer is labeled as B-Horizon which is typically harder and denser
• C-Horizon is composed of cracked rocks of tiny pieces

Major types of Soil in India (Based on the Geographic distribution)

• Types of Soils in India are categorized geographically into two parts-Soils of peninsular and extra-peninsular India
• In peninsular India, soils are mostly formed from the original rocks also known as in situ decompositions of rocks, whereas soils in the extra-peninsular region are formed from the removal action of wind and water
• Peninsular soils, also known as sedentary soils are re-deposited to a restricted range. Soils of the extra-peninsular region are stated as transported soils and are very profound

Alluvial Soils

• Silt deposition by the Indus, Ganga, Brahmaputra Rivers, lead to the formation of Alluvial Soils in India. Alluvial soils in the coastal region also form due to wave actions
• The parent materials of alluvial soils originated in the Himalayan region
• Alluvial Soils cover around 46% of the entire area forming the largest group of soil

Red Soils

• After Alluvial Soil, Red Soil forms the second-largest group of soil. Metamorphic and Crystalline rocks like gneisses, granites, and quartzite are the primary parent rocks of Red Soils
• The texture of Red soils varies from clay to sandy, even loamy
• The presence of iron oxide in diffused form gives the soil a red color

Black Soils

• Black Soils are mostly made of rocks or sediments comprising 62% clay. Volcanic rocks formed on the Deccan Plateau are the parent material of maximum Black Soil. The temperature in these regions is usually high, receiving low rainfall thereby making the group of soil represent hot and dry peninsular regions
• Black Soils found in valleys are highly fertile, whereas those in uplands are lesser fertile

Lateritic Soils 

• Lateritic soils originate in places accepting high rainfall with extreme temperatures followed by alternative dry and wet periods
• Due to heavy rainfall, the nutrients get washed away known as leaching. Soils rich in aluminium and iron oxide compound residues

Forest Mountain Soils

• Heterogeneous soils happening on forest-covered hilly slopes wrap 8.7% of the whole area of the country’s land

Arid Desert Soils

• Arid Desert soils contain Aeolian Sand and clay covering an area of 1.42 lakh km. sq.
• Humus growth is prevented by the presence of sand. 

Saline – Alkaline Soils

• The soil at the top of Saline-Alkaline Soil is saturated with alkaline and saline efflorescence as a result of which it gets roofed with particles of salt
• The soil enters the layer of subsoil in areas having low water tables. Salts get carried away by river water in the areas having a good drainage system

Peaty – Marshy Soils

• Peaty-Marshy Soils mostly grow in humid areas. These soils possess a huge amount of soluble salts and organic content
• They are characterized by their heaviness, black colour, and very acidic nature
• Found in coastal areas of Odisha, Tamil Nadu; Bihar, Sunderbans, Uttarakhand

Conclusion

The layer at the top of earth’s crust with a thin structure formed from the disintegration of rocks due to the actions of wind, water, and glaciers is called Soil. Based on the Geographic distribution, Major types of Soil in India are:-Alluvial Soils, Red Soils, Marshy Soils, Alkaline Soils, Arid Desert Soils, Lateritic Soils etc.India has one of the most important and fertile soils due to which they support growth of wide variety of crops such as Rice, wheat, cotton, jute, potato and vegetables, but they lack in nitrogen, phosphorous and Humus.