CESIUM-137-MEASURED EROSION RATES FOR SOILS OF 5 PARENT-MATERIAL GROUPS IN SOUTHWESTERN SASKATCHEWAN

Despite the wide-spread perception that the soils of southwestern Sask atchewan are particularly erosion prone, few observations have been ma de on soil loss in this area. We used Cs-137 redistribution to examine rates of soil loss associated with five parent-material groups in thi s area. Five sites were sampled in each parent-material group: one unc ultivated site and four cultivated sites. Ten samples were taken at ea ch site from landscape positions that have been shown in previous stud ies to have the highest rates of soil loss. The highest rates (median soil loss of -30 t ha(-1) yr(-1)) were associated with glacial till la ndscapes; medium (-21 t ha(-1) yr(-1)) but highly variable rates of lo ss, with coarse sandy glaciofluvial-lacustrine landscapes; and lower a nd consistent losses of around -12 t ha(-1) yr(-1), with silty glaciol acustrine and aeolian landscapes and with fine sandy glaciofluvial-lac ustrine landscapes. The observed rates of loss can be used to calibrat e models of geomorphic instability for this area.