Comparing landscape-scale estimation of soil erosion in the Palouse using Cs-137 and RUSLE

The objectives were to use the cesium-137 isotopic tracer technique to assess the spatial patterns of net soil movement across 46 ha farmed watershed in northern Idaho and to compare the results with estimates from the Revised Universal Soil Loss Equation (RUSLE). Over the 26-year period following caesium fallout, erosion averaged -11.6 t ha^-1 yr¹ from erosional areas, and deposition averaged 18.6 t ha^-1 yr¹ onto depositional areas. Contour maps of net soil movement were developed using geostatistical techniques showing that convex ridge tops and mid-slope knobs have undergone the most severe erosion. The average erosion rate estimated by RUSLE for the entire watershed was -31.4 t ha^-1 yr¹, suggesting that RUSLE overestimated water erosion. -from Authors