Indian soil has been divided into how many parts by the Indian Council of Agriculture and Research?

🔑 Key Points
The first scientific classification of soil was done by Vasily Dokuchaev.
In India, the Indian Council of Agricultural Research (ICAR) has classified soils into 8 categories. They are:
🟢 Alluvial Soil
🟠 Black Cotton Soil
🟥 Red & Yellow Soil
🟤 Laterite Soil
🌲 Mountainous or Forest Soil
🏜️ Arid or Desert Soil
💧 Saline and Alkaline Soil
🌿 Peaty and Marshy Soil

🌾 Alluvial Soil
→ Alluvial soils are widespread in the northern plains and river valleys.
→ They cover about 40% of the total land area of the country.
→ These soils are mainly derived from the debris brought down from the Himalayas.
→ In the Peninsular region, they are found in deltas of the east coast and in the river valleys.
→ The color of the alluvial soil varies from light grey to ash grey.

🔴 Red & Yellow Soil
→ Also known as the "omnibus group".
→ It covers about 18.5% of the total land area of the country.
→ It is found in regions of low rainfall (eastern and southern parts of the Deccan Plateau).
→ Along the piedmont zone of the Western Ghats, a long stretch of area is occupied by red loamy soil.
→ This soil is also present in parts of Odisha and Chattisgarh and in the southern parts of the Middle Ganga Plain.

⚫ Black or Regur Soil
→ Black soil is also known as “Regur Soil” or the “Black Cotton Soil”.
→ It covers about 15% of the total land area of the country.
→ It covers most of the Deccan Plateau – parts of Maharashtra, Madhya Pradesh, Gujarat, Andhra Pradesh, and some parts of Tamil Nadu. In the upper reaches of the Godavari and Krishna, and the north-western part of Deccan Plateau, the black soil is very deep.
→ The color of these soils varies from deep black to grey.

🏜️ Desert Soil
→ Also known as arid soil, it accounts for over 4.42% of the total land area of the country.
→ The color ranges from red to brown.
→ Desert soils are sandy to gravelly in texture, have low moisture content, and low water-retaining capacity.
→ These soils are saline in nature, and in certain regions, the salt content is so high that common salt is obtained by evaporating water.

🧱 Laterite Soil
→ The name has been derived from the Latin word “later”, which means brick.
→ It accounts for about 3.7% of the total area of the country.
→ These are typical soils of the monsoon climate, which is characterized by seasonal rainfall.
→ With rain, lime and silica are leached away, and soil rich in iron oxide and aluminium are left, leading to the formation of laterite soil.
→ Laterite soil is deficient in organic matter, nitrogen, phosphate, and calcium, however iron oxide and potash are in abundance.

🏞️ Mountain Soil
→ This type of soil is found in the forest regions where rainfall is sufficient.
→ The texture of the soil depends on the mountain environment where they are found.
→ These soils are coarse-grained in the upper slopes and loamy and silty on valley sides.

🌱 Peaty and Marshy Soils
→ These soils are found in regions of heavy rainfall and high humidity, supporting the good growth of vegetation.
→ Peaty soils are rich in humus and organic matter.
→ These soils are generally heavy and black in color.
→ In many places, these soils are alkaline.
→ These are found in southern Uttarakhand, the northern part of Bihar, and the coastal areas of West Bengal, Odisha, and Tamil Nadu.

💧 Saline and Alkaline Soils
→ These soils have high percentages of sodium, magnesium, and potassium, and hence are infertile.
→ The high salt content is mainly because of the dry climate and poor drainage.
→ The texture ranges from sandy to loamy.
→ These soils are found in arid and semi-arid areas and in waterlogged and swampy regions.
→ These soils are deficient in calcium and nitrogen.