Wepp erodibility parameters for andisols under rangeland use in the Patzcuaro lake watershed, Michoacan, Mexico

Abstract

The aim of this study was to determine the soil-erodibility parameters of the WEPP erosion model (Water Erosion Prediction Project) for an Andisol used to raise cattle in the Patzcuaro Lake watershed, Michoacan, Mexico. It was used a solenoid-operated rainfall simulator. Interrill detachment was measured in 0.5 m wide, 1.2 m long plots, and the detachment of flowing water was measured in 1 m wide, 3 m long plots, in both cases it was used a completely randomized design with four replications. Soil moisture affected runoff and interrill erosion, whereas the bulk density of the surface layer was lower in the cropland use than under the rangeland use. The interrill and rill erodibility parameters were 774.7x103 kg sec m-4, and 0.5x10-4 sec m-1. These values in comparison with those reported in the literature permit to establish that the rangeland Andisol under study showed a moderated susceptibility to interrill erodibility and low detchment of flowing water. Soil compaction due to livestock trampling may have limited the erosivity of the concentrated flow and therefore the rill erosion.