Describe two main characteristics of 'Alluvial Soil'.

(i) These have been deposited by three important Himalayan river systems– the Indus, the Ganga and the Brahmaputra.

(ii) The alluvial soil consists of various proportions of sand, silt and clay.

(iii) As we move inlands towards the river valleys, soil particles appear somewhat bigger in size.

(iv) In the upper reaches of the river valley i.e. near the place of the break of slope, the soils are coarse, commonly found in piedmont plains such as Duars, Chos and Terai.

(v) According to their age alluvial soils can be classified as old alluvial (Bangar) and new alluvial (Khadar).

(vi) The bangar soil has higher concentration of kanker nodules than the Khadar. It has more fine particles and is more fertile than the bangar.

(vii) Mostly these soils contain adequate proportion of potash, phosphoric acid and lime, ideal for the growth of sugarcane, paddy, wheat and other cereal and pulse crops.

(viii) Due to its high fertility, regions of alluvial soils are intensively cultivated and densely populated.