The Soils of Elgin County - Agriculture and Agri-Food Canada

5. Proceed to Figure 13 and determine theappropriate drainage class for the site .Guidelines for determining soil drainageclasses are provided in the Ontario Institute ofPedology (OIP) publication "field manual fordescribing soils" (13) . Soil colours should bedetermined using Munsell soil colour charts(15) .6. Proceed to Figure 14 to begin keying the siteto the appropriate soil type or land unit.Figure 14 directs the user to the appropriateland unit if the site falls into one of, thosecategories, or it directs the user to moredetailed soil identification keys in Figures 15and 16 . When using Figure 14, it is necessaryto determine if the materials comprising thesoil profile are similar or contrasting .Materials are considered to be contrastingwithin the soil profile if there are significantdifferences in the gravel and stone content .They are also considered to be contrasting ifthe soil texture of adjacent soil horizons isdifferent by two or more textural classes .These differences often are the result of achange in the mode of deposition of thematerials e.g. lacustrine, morainal, or fluvialdeposition.7. If the materials are similar throughout the soilprofile, use Figure 15 to determine the soiltype for the site. Guidelines for determiningsoil texture classes are provided in the OIPpublication-"field manual for describing soils"(13) .8. If the materials at the site are contrasting, useFigure 16 to determine the soil type for thesite. Use the OIP publication "field manual fordescribing soils" (13) if assistance is needed indetermining soil texture classes.The following example provides furtherexplanation of the procedures which should befollowed to determine the soil type and slope classat a field site.1 . Locate the field site on the appropriate soilmap for the area, and determine the mapsymbol for the delineated area on the map inwhich the field site is found . For the purposeof this example, the symbol is :BECThe symbol indicates that the area where thefield site is found consists of imperfectlydrained Berrien (BE) soils which occur onsimple C slopes of 2 to 5% .2 . Go to the Soil Descriptions section of the soilreport and read the description of Berriensoils . Now go to the soil profile descriptionsin Volume 2 of the report and review thedescriptions for Berrien soils .3. Now measure the slope gradient and length atthe site. For the purpose of this example, theslope gradient is 4%, and the slope length is 75m. Using the slope classes in the OIPpublication "field manual for describing soils"(13), this is a simple C slope.4. Using a Dutch auger, soil probe, or shovel,expose the soil to a depth of 1 m.5 . Now determine the drainage class for the soilat the site. For the purpose of this example,the Munsell soil colour charts (15) indicate thatthe soil colour is 10YR5/3 throughout theprofile, the mottle colour is 10YR5/8, and thedepth to mottles is 60 cm. Using the soildrainage chart in the OIP publication "fieldmanual for describing soils" (13), the soil isimperfectly drained.6. Proceed to Figure 14 and begin to key the siteto the appropriate soil type or land unit. Forthis example, the materials exposed at the siteconsist of 0 to 55 cm of sandy (sandy loam)textured materials which overly 55 to 100 cmof clayey (silty clay) textured materials whichdo not contain coarse fragments of any size.These materials are contrasting according tothe guidelines given in the descriptions box inFigure 14 .7. Since the materials are contrasting, proceed toFigure 16 to key the site to the appropriate soiltype . Based on the soil informationdetermined at the site, the soil type is aBerrien (BE) soil.8. The soil type and slope class determined forthe site, therefore, supports the soil type andslope class identified in the map symbol forthe area. The agricultural capability rating forimperfectly drained Berrien soils which occuron simple C slopes can now be determinedfrom Table 4. If suitability ratings for specialcrops are needed, refer to Tables 6, 7 and 8 . Ifthe potential erosion class is needed, it can becalculated using the soil erodibility (K) factorvalue from Table 9, and the slope length andgradient (LS) factor value from Table 10 .148