Question

Mention two differences between alluvial soil and black cotton soil.

Answer 1

Hint: Soil is a material composed of mineral, organic matter, water , gas and living organisms. Different kinds of soil have different textures, properties and support different types of vegetation.

Complete answer: The Indian Council of Agricultural Research (ICAR) has classified soils into the following eight categories- Alluvial Soil, Black Cotton Soil, Red Soil, Laterite Soil, Mountainous or Forest Soils, Arid or Desert Soil, Saline and Alkaline Soil, Peaty, and Marshy Soil.
The alluvial soils are formed by deposits of river and have sandy loam to clay texture. Alluvial soils are rich in potash and poor in phosphorus. Due to their porosity and water retaining capacity, this soil is suitable for agriculture. Crops like rice, wheat, sugarcane can be grown here.
Black soil mostly has volcanic origins and has clayey texture. This soil is found in the dry and hot regions of the peninsula and the color is black due to residues of titaniferous magnetite or iron and black constituents of the parent rock. The soil is excellent to grow cotton, millets and jowar.
The differences between the two soils are
1)Origins : Black soil has volcanic origins while alluvial soil is formed by deposits of streams and rivers.
2)Region where they are found : Alluvial soil is found in floodplains of India and black soil is found in the Deccan Plateau
3)Chemical composition : Black soil has low levels of phosphates, nitrogen and humus while alluvial soil has adequate levels of potash, phosphoric acid and alkalis.
4)Texture: Black soil is clayey in texture while alluvial soil is loamy in texture.

Note: Alluvial soil in India is further divided into Bhangar and Khadar. Bhangar is the old alluvial found in higher terraces above flood plains. Bhangar has more calcium carbonate nodules than Khadar. Khadar is the new alluvial soil forming the flood plains and is extremely fertile in nature.