South Dakota prairie summer. Photo by Zaxy / Flickr (noncommercial use permitted with attribution/no derivative works).
Official State Soil of South Dakota
Houdek soil was designated the official state soil of South Dakota in 1990. All State Soils
Houdek soils have been mapped on about 600,000 acres in South Dakota and are of major economic importance; often used for range-land or crops (the most common crops are small grains, corn, sunflowers, soybeans, and alfalfa).
The dark color of the surface layer of Houdek soil is a result of decayed prairie grass, plants, and other materials that have been deposited over thousands of years.