Soil erodibility calculations based on different particle size distribution measurements

Abstract

In this study we focused on the factors aff ecting fi nal outputs of the USLE (Universal Soil Loss Equation) model. In doing so, we conducted soil particle size measurements in diff erent institutions (University of Debrecen, University of Szeged and Geographical Institute, Research Centre for Astronomy and Earth Sciences of the Hungarian Academy of Sciences) with a variety of methodologies (laser, aerometer and pipett e methods) on various soil materials (sandy, loamy and clay). Statistical analyses of the eight examined soil samples have been shown some signifi cant and some non-signifi cant diff erences among the particle size measurements. This paper is aimed at i) to ascertain whether these signifi cant diff erences in particle size measurements cause signifi cant diff erences in soil erodibility calculations; and ii) to assess the amount of soil loss calculated by these K factors. The results suggest that regardless of the relatively small percentage between the smallest and the greatest K factor values, the amount of soil loss can be fairly high, especially when erosion occurs on a longer or steeper slope. In the present case, when we compare simulations results, the amount of soil loss is more important than the diff erence in percentage between the minimum and maximum values. Because the percentage of the diff erence can remain the same between the simulations, while the amount of soil loss increases way beyond soil loss tolerance limits.