i. Vertisols get their name from the fact that they are self-inverting.
ii. They contain large quantities of clay that expands when moistened and shrinks when dry.
iii. The repeated swelling and shrinking churns the soil and obliterates any other diagnostic layers before they have a chance to develop fully.
iv. Vertisols occur only on clay exposed to a seasonally dry climate.
v. Soil cracks do not get wide enough in a wet environment, and continuously dry weather would eliminate the cracks by filling them with dust.
vi. Vertisols occur in the United States only in limestone areas of the South and river plains in the West.
vii. Other countries, such as India or Egypt, have sizeable areas of cracking soils.
viii. Vertisols are fertile because expanding clays have a high exchange capacity, but their physical characteristics make them difficult to farm.