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

Field Identification of Soils(1) IntroductionGuidelines for identifying soils at field sites areprovided in this appendix . The purpose ofincluding these guidelines as part of the reportwas to ensure that future data collection on thesoils of Elgin County can be correlated with thepublished descriptions and interpretations . Theguidelines are based on the soil drainagegroupings and mapping methodology used in thecompilation of the 1:50,000 scale soil maps .Flow charts are provided in Figures 13, 14, 15and 16 which will assist extension personnel,consultants and others in identifying soil types atfield sites. Some knowledge of the geology,physiography, and the soils of Elgin Countywould be useful when using the charts. Inaddition, it is important to have an understandingof the mapping system used in the survey . Sincebackground information on these subjects iscontained in preceding sections of the report, it isrecommended that the soil report be thoroughlyreviewed before conducting field investigations .In order to use the flow charts effectively, it isnecessary to be familiar with the techniques forassessing soil properties such as drainage andtexture. Guidelines and descriptions which willassist in the determination of these properties areprovided in the Agriculture Canada publication"CanSIS Manual for Describing Soils in the Field"(12), and also in the Ontario Institute of Pedologypublication "field manual for describing soils" (13) .It is possible to identify the soil type at mostsites using Figures 13, 14, 15 and 16 . At siteswhere it is difficult to determine the soil type, itmay be necessary to consult the soil descriptionsin Volume 1 and the analytical data in Volume 2,before assigning the soil type designation.Field identification of soils should beconsidered under the following conditions:1 . The areal extent of the site under investigationis approaching or less than 12 hectares, whichis the minimum size area that can bedelineated on the 1:50,000 scale soil maps .2 . The site under investigation occurs in an areawhere the soils and topography are quitevariable . Since the map symbols on the150,000 scale soil maps only identify amaximum of two soil types and slope classes,additional soil types or slope classes mayoccur which are not identified in the symbol.These additional soil types or slope classes arereferred to as inclusions. Although their arealextent is usually limited, they can occupy upto 20% of a delineation. Areas where soil andtopographic variability may be high can beinferred from the soil map by looking at thenumber of soil types and slope classes mappedin the general vicinity of the site underinvestigation . In addition, there is a discussionon the variability of each soil type identifiedon the soil maps in the Soil Description sectionof this report.3. The site under investigation covers only aportion of a delineated area . Although themap symbol indicates the relative proportionof the soil types and slope classes within adelineation, it does not identify their spatialdistribution . It is important to understand thatthe soil types and slope classes identified in amap symbol do not necessarily occur in auniform pattern across the delineation . Sincethe area of investigation covers only a portionof the area, it is possible that only one of thesoil types or slope classes identified in the mapsymbol occurs in the area . It is also possiblethat the site may be comprised of inclusions.(2) How to Identify the Soil at a FieldSiteTo identify the soil at a - field site, it isrecommended that the following procedure befollowed :1 . Locate the site under investigation on the1:50,000 soil maps . Using the "Key to the MapSymbols" description on the border of themap, determine the soil types and slopeclasses identified in the map symbol for thearea. It may also be useful to examine thesymbols in the surrounding delineatins, anddetermine the soil types and slope classesidentified in those symbols .2. Refer to the appropriate soil and profiledescriptions in Volume 1 and 2 forbackground information on soil properties .This awareness will facilitate correlation of thedata collected on-site with the publishedinformation.3 . Determine the slope class at the site.4. Expose the soil profile at the site using aDutch auger, soil probe, or shovel . If possible,the soil should be examined to a depth of onemetre .147