SPATIAL VARIABILITY OF WHEAT YIELD, SOIL PROPERTIES AND EROSION IN HUMMOCKY TERRAIN

The spatial distribution of soil properties, erosion and crop yield was studied along a cultivated transect and an adjacent transect in virgin grassland. The mapping unit was in hummocky moraine in the Dark Brown soil zone of central Saskatchewan. Erosion was affected by an interaction between elevation and surface curvature which affected the spatial and statistical distribution of soil properties and yield in the landscape. For the cultivated transect, percent sand was higher on knolls than in depressions, furthermore several soil properties were nonlinearly related to elevation. Decreases in grain yield on convex or planar lower slopes were correlated with erosion and high carbonate contents. Carbonate concentrations were high in lower slope positions in the cultivated transect, particularly at a relative elevation of 1 m, and appeared to be an important soil property influencing yield. Future studies of soil properties and yield on hillslopes may require careful evaluation of both elevation and microtopography in order to elucidate the effects of erosion.