From glacial till and glacio-lacustrine parent material to soil

We have examined the general characteristics of parent materials common to Saskatchewan, let us now turn our attention to the agricultural characteristics of these soils.

a. Glacial till
Glacial till parent material produces the largest portion of agricultural soils of Saskatchewan; about 60% of total arable acres in the province. Glacial till parent material was carried and deposited by the southward advance of the great ice sheets which covered the province during the last ice age. Glacial till is very mixed or heterogeneous material because it includes all types and sizes of materials that were scooped up and carried in the advancing ice sheet. Glacial till parent material therefore contains all particle sizes from clay to boulders. Fortunately the glacier encountered a large quantity of relatively finer materials, hence the average texture of glacial till soil in Saskatchewan is loam to clay loam. The amount of stone included in the material is variable, and to some extent the luck of the draw. As I indicated to you in my first blog, my farm has some disagreeably stoney fields.  These fields still produce well when it rains, but to this day, need a lot of stone picking. The more or less uncontrolled (random) release of parent material from the melting ice sheets produced irregular topography ranging from gently (figure 1) to strongly (figure 2) rolling landscapes. The more rolling the landscape the more likely the fields are to be dotted with sloughs and wet spots. In addition, the steeper the slopes, the greater the likelihood of soil erosion. Notice the lighter coloured knolls in figure 2.

Figure 1, gently to moderately rolling glacial till landscape

Figure 2  Rolling to strongly rolling glacial till landscape

b. Glacio-lacustrine parent material

Lacustrine parent materials were deposited in glacial lakes created during the melt phase of the ice sheets. These glacial lakes were formed because the melt water could not move northward because it was dammed by the ice sheet nor could it flow southward because land to the south was of higher elevation. The water in these large bodies of water was calm, particularly in the winter when ice covered. Therefore the water only carried fine soil particles in suspension. These fine particles slowly settled to the lake bed. Soils developed on these "old lake beds" are fine textured, generally level and stone free (figures 3 and 4). They are particularly well suited for production of lentil, chickpea and other short stature crops

    
                     Figure 3  Lacustrine landscape located in the Black soil zone of Saskatchewan

Figure 4  Lacustrine landscape in Brown soil zone of southern Saskatchewan

In the end most producers would choose lacustrine parent material if they had a choice. Most of us however don't have that choice, we have to play the cards we are dealt. Don't give up on till soils, if they are fertilized appropriately and it rains accordingly, they are capable of excellent production. Don't forget to include the important health benefits associated with glacial till soil; high quality exercise while picking stones.