This data layer is Surface Texture from the Soil Survey Geographic Database (SSURGO). It was developed by the Natural Resources Conservation Service. SSURGO contains information on soils collected by the National Cooperative Soil Survey over the course of a century. Soil surface textures describe the proportions of sand, silt, clay, and organics present within the soil. The surface texture of soil influences both physical processes, including drainage, and biological processes, including vegetation productivity, making it important to understanding the landscape.