Canadian System of Soil Classification

Taxa

• The Canadian system of soil classification uses five different taxa, or terms, arranged in a hierarchy. Soil orders are the broadest category, covering the most basic characteristics. Orders are differentiated from each other based on the processes by which the soils were formed and the total soil environment. Within each order there are great groups, which are distinguished from each other on the basis of how strong the different processes that formed the soils were. Great groups are subdivided into subgroups. These are distinguished by the types of horizons they have. "Horizon" is a technical name for a layer of soil. Subgroups are further divided into families, which are defined by their textures, depths and mineralogy. Each subgroup is then divided into series. Each series is defined by similarities in fine details of texture, structure, thickness, color and composition. (See References 1 & 2)

Orders

• Canada recognizes ten different soil orders. Chernozemic soils were formed under certain types of grassland and near forests. They are dark in color. Gleysolic soils are mottled, and formed under wet conditions. Luvisolic soils formed under deciduous forests and contain silicate clay. Podzolic soils formed under coniferous forests. They are acidic and contain aluminum and iron. Solonetzic soils formed under grasslands in semi-humid conditions. Organic soils formed from deposits of organic matter, and contain a lot of carbon. Cryosolic soils formed in or near the arctic and have permafrost. Vertisolic soils have high clay contents and are often cracked due to repeated cycles of swelling and shrinking. Brunisolic soils have fuzzily defined layers, and formed under a wide variety of conditions. Regosolic soils have not developed horizons, as they are too young. (See References 1)

Applicability

• The Canadian system is not comprehensive. It only classifies those soils found in Canada. Other parts of the world may have soils not recognized by the Canadian system. In this it is unlike the U.S. system, which classifies all of the world's soils. (See References 2)

An Alternative

• Canadians involved in agriculture sometimes use a separate soil classification system, the Soil Capability for Agriculture Classification. It is an interpretive system, and not as objective as the official system. Soils in this system are placed into numbered classes, one to seven, based on their suitability for producing common agricultural crops. (See References 1)