Modeling translocation and dispersion of soil constituents by tillage on sloping land

Recent studies clearly indicated that soil tillage is a major Factor affect ing soil redistribution on arable land. However, existing modeling studies of the redistribution of soil constituents by tillage are largely theoretic al in nature due to the lack of sufficient experimental data. This paper de scribes the results of field experiments carried out with a moldboard plow on different slope gradients showing that an important net downslope transl ocation and dispersion of soil constituents is associated with soil tillage . Both translocation and dispersion are strongly affected by slope gradient . Available experimental evidence suggests that redistribution of soil cons tituents can be modeled by convoluting the displacement probability distrib ution with the spatial distribution of the soil constituent. The convolutio n model presented here was found to be superior to existing models because it accounts for dispersion, directionality of tillage, and topogaphy. A com parison of soil property data with model simulations indicated that soil ti llage is a major factor when assessing the effect of erosion processes on t he variability of soil properties.