SOIL-EROSION POTENTIAL OF FORMER CONSERVATION RESERVE PROGRAM SITES

Conservation Reserve Program (CRP) areas that are returned to crop pro duction will initially be much less erodible than fields which were fa rmed using conventional practices. In this study, a rainfall simulator was used to measure runoff and erosion from former CRP areas in Missi ssippi, Nebraska and South Dakota over approximately a two year period . Soil loss rates measured immediately following tillage on each of th e three sites were similar to values obtained on the undisturbed CRP t reatments. However when left in a fallow condition, the erosion-reduci ng effectiveness of the sod appeared to have lasted less than one year The rapid increase in soil erodibility following tillage was attribut ed to a reduction in surface cover and organic material. The WEPP and RUSLE models are currently used extensively in conservation planning a nd assessment. The experimental data collected in this study were used to derive selected parameter values for use in these models.