1. A prepared mixture of soil (preferably sterilized) usually containing silt, clay, sand and organic matter to a desired specification. It also may contain physical conditioning materials, nutrients, and pesticides which are spread over turfgrass areas for the purpose of improving the surface, adding to the nutrient supplying ability of the soil, or applying pesticides. Used for leveling, smoothing, covering stolons or sprigs in vegetative planting, as an aid in controlling thatch and in maintaining biological balance.
Source: Ohio State University Turfgrass Program