(i) Alluvial Soils: Alluvial soils include the deltaic alluvium, calcareous alluvial soils, coastal alluvium, and coastal sands. This is the largest and most important soil group of India.
The main features of the alluvial soils of India are derived from the deposition caused by rivers of the Indus, the Ganges, and the Brahmaputra systems. These rivers bring with them the products of weathering of rocks constituting the mountains in various degrees of fineness and deposit them as they traverse the plains. These soils vary from drift sand to loams and from fine silts to stiff clays. Such soils are very fertile and, hence, large irrigation schemes in areas of such soils are feasible. However, the irrigation structures themselves would require strong foundation.