Soils differ in structure, color, texture, nutrient content and other physical characteristics due to the environment in which they form and the items which they are composed of. In nature, soils form in layers which when examined is called a soil profile . Scientists study soil profiles by removing a thin, vertical sample of soil. Each distinct layer in the profile is called a horizon . Each horizon has its own physical characteristics including texture, color, and nutrients.
Most soils have five major horizons.
At the front desk you will find samples of each horizon type. Examine these samples and look for their recognizable traits. This is the surface layer composed of fresh or partly decomposed matter. This layer usually contains no mineral soils. This is the second layer down and its main constituents are mineral soils and organic matter that have been partly decomposed.