The main types of soil found in various parts of India are as follows : (i) Alluvial soil. (ii) Black soil. (iii) Red and yellow soil (iv) Laterite soil (v) Arid or Desert soil. (vi) Forest and Mountainous soil. Alluvial soil is the most fertile, widespread and important soil of India. They are riverine soil transported and deposited by the three great river systems— the Indus, the Ganga and Brahmaputra – which have formed the entire Northern Plains. They are also found in the deltas of the Mahanadi, the Godavari, the Krishna and the Kaveri rivers along the Eastern Coastal plains. They also extend in a narrow corridor to Rajasthan and Gujarat. The fertility of the alluvial soil has made the Northern Plains and the Eastern Coastal Plain the most productive agricultural regions of India with a high density of population. The alluvial soil contain adequate proportion of potash, phosphoric acid and lime which are ideal for cultivation of paddy, wheat, other cereals and pulses and sugarcane. The alluvial soilconsists of various proportions of sand, silt and clay. The soil near the floodplain are more or less fine and in the deltas they are finest. They are coarse in the upper reaches of the river valley specially near break of slope and in piedment plains like Duars,Chos and Terai. Alluvial soils are renewed every year during annual floods. The new, fertile, light coloured and fine alluvial deposited near the river is called khadar. The old alluvial deposited earlier are found at about 30 metres above the floodlevel of the rivers. They are clayey, dark in colour,coarse with kanker nodules and less fertile.