PROF1 RATE = Soil Profile 1
The soil profile is the environment in which the crops' roots grow. Profile ratings are based on the depth, structure, texture and chemical make-up of the soil. The highest ratings (maximum of 20-points) are given to those soil profiles in which the soil has developed to a depth of 12 inches or more; the soil has good structure (not hard or blocky); the soil has favourable texture (is not gravely or sandy); and the soil is not full of calcium carbonates or sodium.
Lighter textured soils have mainly large, continuous pores that transmit water very quickly. Rainwater quickly moves down through a sandy soil. A profile adjustment factor has been introduced to decrease the profile rating assigned to lighter textured soils. The profile adjustment factor is based on the moisture holding capacity of the soil texture that makes up the soil profile. It applies only to soils of texture lighter than a loam. The lighter the soil texture, the lower the profile adjustment factor and, therefore, the lower the profile rating will be. Since the soil texture in this example is clay loam to loam, no profile adjustment factor is warranted.
In this example the soil profile is developed to a depth of eight inches and is calcareous (has calcium carbonate in the profile). The soil profile is a CAL8, which is rated at 10-points. This profile rating has not been reduced by a profile adjustment factor because this Weyburn soil has a texture greater than Loam texture (profile adjustment factors, if present, are not shown on the detail profile).
On this particular sample profile there is not a second different soil association, but rather, the second soil association is Weyburn. When there is a second soil profile rating, or second topsoil rating, the soil association has to be entered again as the second soil association. Sometimes there are two different soil associations with two organic matter ratings, four texture ratings, two profile ratings and two topsoil ratings. In these instances, the organic matter ratings, profile ratings, texture ratings, and topsoil ratings are each added together and averaged.
On this sample detailed profile there are two soil profiles for soil association 1. The second soil profile (PROF2 RATE) is usually the soil profile that is rated in the soil area. In this particular example, the soil profile is OR10. The soil development is to a depth of 10 inches and the profile rating is 18 points. The average profile rating is then 14 points (18 +10) ÷ 2.
If more information is required on soil profile ratings, the reader should consult The Canadian System of Soil Classification.