Alluvial soils are largely distributed in the river valleys and northern plains.
- Out of the total area of India, Alluvial soils cover 40%.
- In the Peninsular region, Alluvial soils are found in river valleys and in deltas of the east coast.
- Through a narrow corridor in Rajasthan, they extend into the plains of Gujarat.
- Alluvial soils are transported and deposited by rivers and streams. Alluvial soils are depositional soils.
- The colour of the alluvial soils varies from the light grey to ash grey.
- Alluvial soils are poor in phosphorus and generally rich in potash.
Alluvial Soil – 2 different Types
There are 2 different types of alluvial soils which are mentioned below:
- Bhangar – represents a system of older alluvium, deposited away from the flood plains.
- Khadar – The new alluvium which is deposited by floods annually is Khadar.
Soil Classification – Parameters
The soils of India have been classified into 8 different types based on the following 4 different parameters:
Classifications of Soils in India – 8 Types
- Alluvial soils
- Black soils
- Red and Yellow soils
- Laterite soils
- Arid soils
- Saline soils
- Peaty soils
- Forest soils.
Details on Alluvial soil are given above, brief details on other 7 different types of soils are given below:
Red and Yellow Soils
- Red soil develops on crystalline igneous rocks in the southern and eastern part of the Deccan Plateau. This soil is found in the areas of low rainfall.
- Moisture can be retained for a very long time by Black soil.
- Black soils are also known as the Black Cotton Soil or Regur Soil.
- The black soils are usually impermeable, deep, and clayey.
- Arid soils lack humus, organic matter and moisture.
- Arid soils range from red to brown in colour.
- Arid soils are usually found in Western Rajasthan.
- The laterite soils are found in areas having heavy rainfall and high temperature.
- Laterite has been derived from the Latin word ‘Later’ which means brick.
- Laterite soils are poor in calcium, organic matter, phosphate, and nitrogen content.
- Forest soils are formed in the forest areas where sufficient rainfall is available.
- Forest soils found in the lower valleys are fertile.
- Forest soils are coarse-grained in the upper slopes and silty and loamy on valley sides.
- Saline soils are also known as Usara soils.
- Saline soils does not help in vegetative growth as they are infertile.
- Saline soils are infertile due to high proportions of potassium, sodium, magnesium.
- Saline soils are found in waterlogged, semi-arid regions, swampy regions, and arid areas.
- Saline soils lack calcium and nitrogen.
- Saline soils are distributed across Sunderban areas of West Bengal, deltas of the eastern coast, and western Gujarat.
- There is good growth of vegetation in these soils.
- The soil is rich in organic matter and humus.
- The percentage of Organic matter in Peaty soils are in the range of 40 to 50%.
- They are found in the areas of heavy rainfall and high humidity.
- It is widely found in the coastal areas of Orissa, West Bengal, and Tamil Nadu,southern part of Uttaranchal, and in the northern part of Bihar.