Terrain attributes, landform segmentation, and soil redistribution

Abstract

The 137 Cs technique has greatly expanded our knowledge of the topography–soil redistribution relationship. For the technique to be useful in upscaling of process models and regional-scale conservation planning, we must be able to show that a consistent relationship exists between 137 Cs -derived soil redistribution rates and terrain attributes in a given region. In this paper, the association between 137 Cs -derived soil redistribution rates and quantitatively defined landform elements was examined at nine hummocky terrain sites in southern Saskatchewan, Canada. Shoulder (SH) elements with convex plan curvatures had the highest mean soil loss rates of 33 t ha −1 yr −1, followed closely by other SH and backslope (BS) elements. The erosional behavior of level elements (i.e. those with gradients less than 3°) was highly dependent on the specific dispersal area (SDA) of the element—elements with high dispersal areas were dominantly erosional (mean soil loss of 14 t ha −1 yr −1), whereas level elements with low dispersal areas were depositional (mean soil gain of 15 t ha −1 yr −1). Doubly concave footslope (FS) elements had mean soil gain of 10 t ha −1 yr −1. The dispersion of values across the nine sites was much greater for the depositional units than the erosional units, indicating a complex relationship between deposition and terrain attributes in the depositional units. The results clearly indicate that regional-scale patterns of soil redistribution can be developed using the 137 Cs technique.