Explain black soil?

Black soils also called as black cotton soils,  internationally known as 'tropical black earths' or 'tropical chernozems' .It is developed by the weathering of the Deccan lava in majorparts of Maharashtra, western Madhya Prades (Hoshangabad, Narsinghpur, Damoh, Jabalpur, Raisen and Shahdol districts), Gujarat (Surat, Bharuch, Vadodara, Kheda, Sabarkantha and Dang districts), Andhra Pradesh etc.The colour of these soils varies from deep black to light black and Black soils are highly retentive of moisture, extremely compact and tenacious when wet, consid­erably contracted developing deep wide cracks on drying and self-ploughing. Black soils are credited with high fertility. These are well suited to legumi­nous crops like cotton, turn and citrus fruits. Other crops include wheat, jowar, millets, linseed, castor, tobacco, sugarcane, safflower, vegetables etc. On the uplands these soils are comparatively less fertile than on the low lands