Assessment of Soil Erosion in Saskatchewan
Begg, Caroline Beatrice Meyer
The objectives of this study were to determine which soil fractions were removed during the erosion process and to estimate soil loss by the use of a radionuclide tracer, Cesium-137. Soil fractions removed by erosion were collected during the operation of a wind tunnel and a rainfall simulator at four sites. Two pairs of basins, one in the Dark Brown soil zone and one in the Black Soil Zone I were sampled for 137 Cs levels. Each pair consisted of a cultivated and uncultivated basin. All soil samples were analyzed for organic carbon, total nitrogen and phosphorus content, particle size distribution, and l37Cs levels. The suspension of the wind and water erosion was generally enriched in carbon, nitrogen, and clay. wind erosion selectively removed organic carbon from the soil. At three sites the wind and water erosion suspension was enriched in l37cs• At the fourth site, the water suspension was lower in 137Cs than the soil, however, the wind suspension was somewhat enriched in l37cs• Analysis of the combined wind and water erosion ·samples indicated a strong relationship between 137cs and organic carbon, and clay. An inverse relationship between 137Cs and elevation was observed in the cultivated basins. The length-slope factor in the Universal Soil Loss Equation showed no consistent relationship to 137cs distribution. This was probably due to the loss of soil on the knolls and deposition in the lower areas of cultivated basins. Significant differences were found between l37Cs levels at different slope positions in the cultivated basins, but not in the non-eroded control basins. Estimates of the soil redistribution within the basins were obtained using a 1 to 1 relationship between 137Cs levels and soil movement.