5.5 The Soils of Canada

Up until the 1950s, the classification of soils in Canada was based on the system used in the United States. However, it was long recognized that the U.S .system did not apply well to many parts of Canada because of climate and environmental differences. The Canadian System of Soil Classification was first outlined in 1955 and has been refined and modified numerous times since then.

There are 10 orders of soil recognized in Canada. Each one is divided into groups, and then families, and then series, but we will only look at the orders, some of which are summarized in Table 5.2. The distribution of these types of soils (and a few others) in Canada is shown in Figure 5.5.1.

There is an excellent website on Canadian soils, with videos describing the origins and characteristics of the soils, at: Soil Classification: Soil Orders of Canada.

As we’ve discussed, the processes of soil formation are dominated by the downward transportation of clays and certain elements dissolved in water, and the nature of those processes depends in large part on the climate. In Canada’s predominantly cool and humid climate (which applies to most places other than the far north), podsolization is the norm. This involves downward transportation of hydrogen, iron, and aluminum (and other elements) from the upper part of the soil profile, and accumulation of clay, iron, and aluminum in the B horizon. Most of the podsols, luvisols, and brunisols of Canada form through various types of podsolization.

In the grasslands of the dry southern parts of the prairie provinces and in some of the drier parts of southern B.C., dark brown organic-rich chernozem soils are dominant. In some parts of these areas, weak calcification takes place with leaching of calcium from the upper layers and accumulation of calcium in the B layer. Development of caliche layers is rare in Canada.

Organic soils form in areas with poor drainage (i.e., swamps) and a rich supply of organic matter. These soils have very little mineral matter.

In the permafrost regions of the north, where glacial retreat was most recent, the time available for soil formation has been short and the rate of soil formation is very slow. The soils are called cryosols (cryo means “ice cold”). Permafrost areas are also characterized by the churning of the soil by freeze-thaw processes, and as a result, development of soil horizons is very limited.

Image Descriptions

Figure 5.5.1 image description: Soil order map of Canada. Chernozem is found in the southern parts of the prairies provinces (Alberta, Saskachewan, and Manitoba). Luvisol is found in the BC interior, most of central and northern Alberta, and a strip through central Saskatchewan and Manitoba. Podsol is common on the eastern and western coastal areas, as well as northern BC, and much of Quebec and the maritime provinces. Brunisol is common in the southern parts of the territories, northern Sakachewan and Manitoba, as well as parts of Ontario and Quebec. Organic soil is scattered all over the country, but most concentrated in northern Ontario and the lowlands around Hudson Bay.  Cryosol is predominant in the far north. [Return to Figure 5.5.1]

Media Attributions

• Figure 5.5.1: Image © Department of Soil Science, University of Saskatchewan. All rights reserved. Used with permission.