SOIL-LANDSCAPE ANALYSIS IN RELATION TO SOIL DISTRIBUTION AND MAPPING AT A SITE WITHIN THE WEYBURN ASSOCIATION

Abstract

Soil-landscape relationships were studied in detail at a site comprised of Dark Brown and related soils of the Weyburn Association in central Saskatchewan. Detailed soil observations along transects identified actual soil series and related their distribution to landscape parameters. A slope-profiling approach, involving division of slopes according to angular differences between measured lengths along the transects, revealed that while soil distribution varied in terms of slope position, slope length, slope gradient and sequence, the most significant relationship lies between soil distribution and shape of slopes. Most slopes could be subdivided readily into convex units, concave units, usually short rectilinear units joining them, and depressional units. Such divisions generally coincided with observable soil divisions, corresponding, respectively, with shallow, deep and gleyed soils. The convex units comprised Regosols and Rego, Calcareous and ’shallow Orthic’ Dark Brown Chernozemic soils. The concave units included ’deep Orthic,’ ’AB Orthic’ and Eluviated series. The depressional units were generally composed of Gleyed Orthic or Gleyed Eluviated series. Both field and laboratory analyses confirm that the soils within landscapes form a continuum, but that recognition of the soil groupings suggested provide a practical and feasible field separation in mapping soils. A combination of aerial photos, field examination of soils and an evaluation of slopes and particularly slope changes could be used to recognize and map these broad, landscape-related soil groupings. Key words: Soil association, soil catena, soil series, slope analysis, topography, map units