Placement of Medium and Deep Cracking Clay Soils in the Comprehensive System of Soil Classification

Leptic and calcic subgroups are suggested as appropriate additions for a satisfactory classification of Vertisols that have a solum thickness of 50 to 100 cm.

In regard to the classification of cracking clay soils of solum thickness of 25 to 50 cm, the need for recognizing a “Vertic epipedon” is brought out and the definition of its diagnostic features is presented. Based on the recognition of the suggested “Vertic epipedon”, a new suborder “Vertepts” is proposed with four great groups under it.

In the light of the above suggestions, a revised classification scheme in respect of cracking clay soils of various sola thicknesses is presented.