Cal Poly Soil and Water Resources Presented by Dr. Del Dingus

The Diablo soil is classed as a Vertisol. It has the capacity to invert itself through the shrinking and swelling process. During summer when the soil is dry it shrinks and contains large cracks. Material on the surface fall down the cracks to the bottom. Repeated cycles of shrinking and swelling will create a churning effect in the soil. The Diablo soil is used mostly for pasture land where slopes are over 8%. On gentle slopes the soil can be dry farmed or even irrigated for vegetable production with success. It is especially difficult to cultivate when wet. Building on the soil presents special challenges.