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.
Clay particles also pack together tightly, allowing for little air space. As a result, plant roots suffer from a lack of oxygen. Sand particles do not hold water or nutrients well. The best soil for plant growth is one in which all three types of particlesâclay, silt, and sandâare in balance. Such a soil is called loam. Soil horizons and profile Once soil has developed, it is composed of horizontal layers with differing physical or chemical characteristics and varying thickness and color.