The last layer in the Houdek soil is the parent material. This layer represents the materials from which the Houdek soil has developed with time. It represents what the glacier originally left at the soil surface. Other soils in SD differ from the Houdek soil because they have different characteristics and properties, much like a collie dog is different from other breeds of dogs. Soils that are found east of the Houdek series tend to have higher organic matter levels, are more moist, and are used more intensively for row crop production.
Some soils are underlain by gravel and others are poorly drained.
Because soils are complex, variable, and occur as a mosaic on the land, it is difficult for one to learn them all. However, if one learns the properties of the state soil, Houdek, then other soils can be compared to it. Soils take thousands of years to form and it only takes a few years to destroy their productivity as a result of erosion and other types of improper management. Soils are used to produce crops, range, timber, and for recreation. They are used for engineering purposes and are an integral part of the water cycle.