Explanation:

Explanation: Black soil in India is rich in metals such as Iron, Magnesium and Aluminium. However  it is deficient in Nitrogen, Potassium, Phosphorous and Humus. Black soil is of red colour mainly  due to its iron oxide content. This soil shares 15 % of all types of soil in India. These soils are made  up of volcanic rocks and lava-flow. It is concentrated over Deccan Lava Tract which includes parts  of Maharashtra, Chhattisgarh, Madhya Pradesh, Gujarat, Andhra Pradesh and Tamil Nadu. Typical characteristics of this black soil are swelling (during wet period) and shrinkage (dry period). While  dry, it  forms very deep cracks of more than 30-45 cm. In Kovilpatti (Tamil Nadu) areas the cracks  may extend to 2 to 3 m with a width of 1 to 6 cm. Field preparations takes longer time compared to  other soil. Only after secondary tillage, the soil is suited for crop production. The soils are fine  grained contain high proportion of Calcium and Magnesium carbonates. Black soil holds more  moisture and available for a long time.In Tamil Nadu Black soils have high pH (8.5 to 9) and are rich  in lime (5-7%), have low permeability. The soils are with more cation exchange capacity (40-60  m.e./100 g). Crops cultivated from this type of soil are Rice, Ragi, Sugarcane and Cashew nuts etc.  This type of soil formed as a result of high leaching and found in the areas of high rainfall.
Important features of black soil:
• Regur means cotton – best soil for cotton cultivation.
• Most of the Deccan is occupied by Black soil.
• Mature soil.
• High water retaining capacity.
• Swells and will become sticky when wet and shrink when dried.
• Self-ploughing is a characteristic of the black soil as it develops wide cracks when dried.
• Rich in: Iron, lime, calcium, potassium, aluminum and magnesium.
• Deficient in: Nitrogen, Phosphorous and organic matter.
• Colour: Deep black to light black.
• Texture: Clayey.