Houdek loam was designated as a South Dakota state symbol by the 1990 legislature. It is pronounced hoo-dek. This soil and similar soils have been mapped on about 600,000 acres.
Soil scientists, working with the United States Soil Conservation Service (now Natural Resources Conservation Service), have identified over 500 different soils in South Dakota. Houdek soil, a deep, well drained, loamy soil, represents many soils formed in South Dakota under the influence of prairie grass. The surface layer is dark colored from decayed plants and other material that has been deposited over thousands of years.
Houdek soil is of major economic importance to South Dakota because the productive Houdek soils are often used for cropland and rangeland. Small grains, corn, sunflowers, and soybeans are commonly grown crops. Alfalfa and grass-alfalfa mixtures provide hay and pasture for grazing livestock. Large areas of Houdek soil are in native range. Crops and grasses grown on the Houdek soil also provide habitat for wildlife.