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

of soil profiles and horizons which commonlyoccur in the County are shown in Figure 10.Typical soil profiles and horizons for many of thesoils which occur in the County are provided inVolume 2.The major mineral soil horizons are designatedas A, B, and C starting with the surface layer andmoving downward in the profile. Based ondifferences in soil properties, subdivisons of thesehorizons are designated by adding lower casesuffixes to them, for example Ah, Ap, Bm, Btgj,Ckg, etc .The A horizon is most often the surfacehorizon, and usually exhibits a dark brown colourdue to enrichment with organic matter . In ElginCounty, the surface horizons usually have beencultivated and are designated as Ap horizons .They generally are non-calcareous and neutral toacid in reaction .TheB horizon underlies the surfaceA horizon,and is a chemically or physically altered layerresulting from extensive weathering and manyyears of soil formation. While the B horizon maybe slightly enriched with organic matter, it usuallydoes not exhibit the dark brown colour associatedwith the surface A horizon. In Elgin County,these horizons also are generally non-calcareousand neutral to acid in reaction. Examples of someB horizon designations which commonly occur inthe County are clay enriched Bt or Btgj horizons,and gleyed Bg horizons.The C horizon, which is commonly referred toas the soil parent material, consists of material thathas undergone I relatively little weatheringcompared to the overlying A and B horizons.Textures of these horizons in the County rangefrom heavy clays to coarse gravels. They usuallyare calcareous and mildly alkaline in reaction .Some common C horizon designations in theCounty are Ck, Ckgj, and Ckg.percent. In some map symbols, the Gobles soilmay occur on two slopes, for example GO/D>C .In this instance, Gobles soils occurring on D slopesare dominant (40 to 80 percent of the area), andGobles soils occurring on C slopes are significant(20 to 40 percent of the area) .Many symbols shown on the soil maps havetwo soil types or components . For example, theBV>TO.L/C>b map symbol is composed of twosoils, the Beverly soil (BV) and the Toledo loamyphase soil (TOI). The Beverly soil is dominant(40 to 80 percent of the area), and occurs on asimple C slope of 2 to 5 percent. The Toledoloamy phase soil is significant (20 to 40 percent ofthe area) and occurs on a complexb slope of 0.5 to2 percent.Descriptions of the components whichcomprise the symbols shown on the soil maps,and their proportions of occurrence, are providedon each map in the section titled "Key to the MapSymbols". Descriptions are also given in theGlossary at the back of this report .Miscellaneous Land UnitsA number of miscellaneous land unitdesignations were applied to areas in the County .Some areas designated as this type of unit areeither too variable or complex to identifyindividual soil series or phases of soil series .Other types of miscellaneous land units includeareas which have been disturbed, modified, orpermanently withdrawn from agricultural use .The types of miscellaneous land units applied toland areas are: Alluvium (AL), Eroded Channel(ER), Not Mapped (NM), Organic (OR), Scarp(SC), and Valley Complex (VC) .Soil Map SymbolsThe symbols shown on the soil maps are ineffect map units, and represent either 1 or 2 soils,or a miscellaneous land unit, that occur within anyarea on the soil map enclosed by a boundary. Thesoils and their respective slopes are identified inthe map symbols, and in the legend provided oneach soil map, by capitalized or small case letters.An example of a soil map symbol whichcontains only one soil type or component is theGO/D map symbol. The soil identified in thissymbol is the Gobles soil (GO) . The slopeassociated with this soil is always shown in thedenominator, and is a simple D slope of 5 to 919