Chapter 3: Outline of the System and a Key to the Classification of a Pedon
Outline of the System
The Canadian system of soil classification at the order, great group, and subgroup levels is tabulated alphabetically according to the names of the orders.
Classifying a Pedon
The taxonomic class of a pedon can be determined by using the definitions and keys in this and other chapters. A knowledge of soil horizon definitions and soil terminology as presented in this publication is required to use the keys. Definitions of these terms in relation to soil climate are in Chapter 14.
Keys to soil orders, soil great groups, and soil subgroups are presented in this chapter. Complete definitions of each order, great group, and subgroup are contained in the chapter on each order. All the keys are arranged in a systematic order and are based on diagnostic soil criteria (or criterion). Keys for soil families and soil series within subgroups are not included in this publication. However, family differentiae are specified in Chapter 14, and an up-to-date list of approved series (CanSIS Canadian Soil Names File) is maintained by the Eastern Cereal and Oilseed Research Center, Ottawa.
The following procedure should be used to key out the classification of a pedon:
- Expose a vertical section through the pedon, describe the horizons, and take appropriate samples if the designation of some horizons must be checked by laboratory analysis. In some cases the final classification must await the laboratory data.
- Study the Key to Soil Orders in this chapter and select the first order in the key that apparently includes the pedon involved.
- Turn to the page indicated and verify that the definition of the soil order includes the pedon concerned. Then using the Key to Soil Great Groups, select the appropriate great group.
- Turn to the page indicated and verify that the definition of the soil great group includes the pedon concerned. Then using the Key to Soil Subgroups, select the appropriate subgroup.
- Turn to the page indicated and verify that the definition of the soil subgroup includes the pedon concerned.
- To classify the pedon at the family level, turn to Chapter 14 and select the family designation that applies; e.g., loamy, mixed, shallow, acid, cold, humid family.
- To classify the pedon at the series level, refer to a recent soil survey report for the area, or confer with the soil correlator of the province or territory.
For those familiar with Canadian soil taxonomy and the soils of the area under study, the detailed step-by-step procedure usually is not necessary. However, even experienced pedologists must await laboratory data before classifying some pedons. Periodically users of the system will encounter pedons that do not appear to fit any of the soil classes defined. If the pedon appears to represent a significant area (i.e., more than 800 ha) then describe it thoroughly, collect samples for analysis, indicate the properties that make it difficult to classify, and notify the soil correlator of the province or territory involved.