Geology of Southwest
Saskatchewan
*Soil Map of Southwest Saskatchewan
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Legend:
Dark Brown - Chernozemic Light Brown - Solonetzic
Purple - Vertisolic Yellow - Regocolic
The topography
that makes up the region of southwestern Saskatchewan does not quite fit
the stereotype of what most Canadians appreciate of Canada. Since
most of the region receives around 11 to 14 inches of precipitation per
year, the climate of the southwest is classified as semi-arid (the physical environment takes in more water, than it gives back). The
main economical activities of the region include extensive ranching and
farming (various cereal and broadleaf crops, with several numbers of successful organic priorships); along with oil, natural gas and sodium sulfate mining. Record
highs of 114 degrees Fahrenheit (45 degrees C) and a lows of -62 degrees
Fahrenheit (-52 degrees C) have been recorded in southwest Saskatchewan,
which proves that the region experiences excessive temperature and climate extremes.
The natural
vegetation in the southwest portion of Saskatchewan consists of mid grasses;
typically known as spear grass, wheat grass, june grass, and blue grama
grass. A correlation can be developed in what vegetation grows over
(or develops) each soil type. The june and wheat grasses mostly occupy
areas close to sufficient sources of moisture such as streams, lakes and
rivers, thus they grow on vertisolic type soils (moisture retentive).
Areas where spear and blue grama grasses thrive are usually light chernozemic
structured soils, while areas where just blue grama grasses occur reside
in poorly structured solonetzic soils. Along with the abundance of
grasses, plant life such as silver sagebrush and cactus also prosper in
the southwest. The only exception to this vegetation classification
occurs in the Cypress Hills, where lodge pole pines and white spruce pines
dating less than 120 years in age ensue. The typical soil type of
the Cypress Hills region and upland (area exceeding in excessive elevation)
is classified as dark brown chernozemic soil.
Generally
speaking, most soil types consist of three different layers/horizons.
The first layer (A horizon), consists of the dark, top part of the soil
where most of the organic (humus) material is present. This is the
layer where most of the plowing occurs in cultivated soils, having a depth
of around 4 to 6 inches. The second layer, labeled as the B horizon,
is heavier and drier in texture than the A horizon, and occurs from about
4 to 24 inches. The third layer, known as the C horizon, consists
mostly of unaltered material that is poor in nutrient value. Thick
rock formations may also be found in this layer.
The three
dominate soil types of the southwest are chernozemic, solonetzic and vertisolic.
The interesting situation with these three different soil types is that
only one of them - chernozemic, has a regular horizon structure as the
diagram described above. Solonetzic type soils have only one horizon
layer, which is similar to the C horizon of the above diagram. Such
soils occur on moderately rolling plateaus and valley complexes.
The third type of soil, vertisolic, also has one horizon layer such as
solonetzic soils. However, vertisolic soils have one layer which
resemble the A horizon, making them very moisture and nutrient retaining.
With this said, one cannot judge or label what soils / regions in southwestern Saskatchewan are the most efficient.
It is well known, that soils of the solonetzic type can produce as good or better crops than those grown in vertosolic soils.
These are some of unique challenges that face Saskatchewan's southwest.
*Map used with permission from the University of Saskatchewan. (not posted online)
Reproduced from the Atlas of Saskatchewan: Millennium Edition.
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