Integrated Crop Management is published by the Department of Entomology , Iowa State University , Ames, Iowa. Iowa's soils range in thickness from a few inches to several feet.
All soils consist of solid materials and pores.
Soil solids consist of mineral particles and organic matter. The pores are filled with air, water, or both. The ratio of soil solids to pores in a defined volume is a measure of soil density. A soil's parent material influences the soil texture, or the ratio of sand, silt, and clay-sized particles occurring in the soil layers. The percentage of each size fraction in a soil layer can be interpreted by textural classes.