Houston Black -- Texas State Soil
Houston Black Soil Profile
Surface layer: black clay
Black series occurs on about 1.5 million acres in the Blackand Land
Prairie, which extends from north of Dallas south to San Antonio. Because
of their highly expansive clays, Houston Black soils are recognized
throughout the world as the classic Vertisols, which shrink and swell
markedly with changes in moisture content. These soils formed under
prairie vegetation and in calcareous clays and marls. Water enters the
soils rapidly when they are dry and cracked and very slowly when they are
Houston Black soils are used extensively for grain sorghum, cotton, corn, small grain, and forage grasses. They also occur in several metropolitan areas, where their very high shrink-swell potential commonly is a limitation affecting building site development.
The Professional Soil Scientists Association of Texas has recommended to the State Legislature that the Houston Black series be designated the State soil. The series was established in 1902.