Vertisol is found highest in the state of

Black soils (Vertisols) are also called "regur" or black cotton soil because cotton is the most important crop grown on these soils.
The second largest soil group in India covers about 74 mha total area of the country.
Developed from basaltic rock under semi-arid to sub-humid conditions.
pH ranges from 7.8 to 8.7 which may go up to 9.5 under sodic conditions.
Highly clayey with clay content of 30 to 80%
Rich in Montmorillonite minerals, they have a high cation exchange capacity (30-60 meq/100 g soil).
One of the characteristics of black soil is that it swells on wetting and shrinks and cracks when dry, also called as self-plowed soil. 
These soils are rich in Potash and lime but deficient in Nitrogen and Phosphorus.
Maharashtra is the maximum area having (20.63 mha) followed by Madhya Pradesh (16.27 mha) and Gujarat (8.79 mha).