Eight major types of soil can be found on the Indian subcontinent. Each type is classified on the basis of the minerals it contains, the acidity levels of that particular soil, and the texture, color and general appearance of the soil.
Red soils are usually found in the dry regions of India with low rainfall, such as Andhra Pradesh, Bihar, Goa, Maharashtra, Karnataka and Tamil Nadu. Its red color is due to the high presence of iron oxides. These soils are low in lime, phosphorous and nitrogen. They have developed from metamorphic rocks.
Laterite soil is usually found in the tropical regions of Indian with heavy rainfall, such as the southern half of the Western Ghats and the Eastern Ghats on the coast of Orissa. Laterite soil contains high levels of iron and aluminum oxides, and clay with a low lime content, which results in a pH value of 5 to 6.
Alluvial soils are the most widely used for agriculture. They are found mostly in the northern plains distributed on the Indo-Gangetic plain and the Brahmaputra valley. Alluvial soil is low in nitrogen and phosphorous, and is sandy. It varies from lightish grey to dark in color.
Black soils are so called because of their dark color, which is due to the high value of phosphorus and lime, and the low nitrogen content present. The high clay content results in poor drainage and a neutral composition. This soil is ideal for the cultivation of cotton.
Mountain soil is found in the northern regions of India towards the Himalayas. This type of soil is slightly acidic with high humus content and is dark brown in color.
Desert soil contains high amounts of nitrate, phosphate and other soluble salts. As a result, this type of soil is very productive in the presence of water. The color varies from yellow red to light brown. Found in the states of Haryana, Punjab and Rajasthan, these soils have a pH of 8 to 8.5 with low nitrogen content.
Found on the coasts of Orissa and Kerala, sodic soil contains toxic salt levels and is highly acidic. The salt content is dominated by chlorides and sulfates, which affect plant growth. Sodic or alkaline soils contain exchangeable sodium salts.
Marshy soil remains submerged under water during the monsoons and also during the drier seasons. Rice is cultivated in marshy soil. It is found in highly humid regions and is highly acidic with a pH value of 3.5.