2. Black soils (Vertisols)

• A typical black soil has a high clay content of 62% or more.
• The black soils have high moisture retention capacity, and are generally neutral to slightly alkaline.
• When dry, soil shrinks and develops deep cracks permitting oxygenation of the soil to sufficient depths and thus enhancing fertility.
• The black colour is due to the presence of a small proportion of Titaniferous Magnetite or Iron and black constituents of the parent rock.
• They generally contain 10% Alumina, 9-10% Iron Oxide, 6-8% lime and Magnesium Carbonates, less than 0.5% Potash and are low in Phosphates, Nitrogen and humus.
• This soil has been used for growing a variety of crops for centuries without adding fertilizers and manures.