Petersburg, West Virginia. Petersburg is a city in Grant County, West Virginia, USA. The population was 2,467 at the 2010 census. It is the county seat of Grant County. Contents.
The particles that make up soil are categorized into three groups by size: sand, silt, and clay. Sand particles are the largest and clay particles the smallest. Although a soil could be all sand, all clay, or all silt, that's rare. Instead most soils are a combination of the three.
Soil profile refers to the different layers, or horizons, of soil. The first is made up of decomposed matter, such as leaf litter. The topsoil horizon also contains organic materials and is dark brown to black. This layer is great for plants. Leaching matter makes up the third horizon of the soil profile, which consists mainly of sand, silt, and clay.