GGR100H1 Chapter 18: Chapter 18- textbook
Document Summary
A soil profile should be studied from the surface to the deepest extent of plant roots or to where regolith or bedrock is encountered. Such a profile is a pedon, a hexagonal column measuring 1 to 10 m^2. A pedon is the basic sampling unit used in soil surveys. Many pedons together in one area make up a polypedon which has dsitinctibe characteristics differentiating it from surrounding polypedons. A polypedon is an essential soil individual comprising an identifiable series of soils in an area. Each distinct layer exposed in pedon is soil horizon. A horizon is roughly parallel to the pedons surface and has characteristics distinctly different from horizons directly above or below. At the top of the soil profile is the o( organic) horizon named for its organic composition derived from plant and animal litter that was deposited on the surface and transformed into humus. Humus is not jus a single material; material usually dark in colour.
