Combining plot measurements and a calibrated RUSLE model to investigate recent changes in soil erosion in upland areas in Southern Italy

Purpose: In recent decades, soil erosion has been recognized as a serious environmental problem in many countries of the world and the impacts of climate change have focused attention on potential changes in erosion rates that could further increase such problem. These impacts are documented by a general decrease of annual precipitation and a corresponding increase in the number of heavy rainfall events, intensity and frequency that accelerate the loss of fertile soil material. Materials and methods: Direct observations of soil loss obtained during the period 2006–2016 on five experimental plots in Southern Italy were preliminarily presented and discussed. These measurements were used to calibrate the RUSLE model that, coupled with independent long-term measurements of rainfall erosivity, allowed calculation of soil erosion from 1954 to date. Results and discussion: The plot measurements showed annual values of soil erosion generally higher than the long-term estimates provided by the RUSLE (1954–2019) suggesting an increasing trend of soil erosion rates during the last 20–25 years. On the contrary, a decreasing trend of the annual rainfall measurements can be observed for the same period. Conclusions: The overall results demonstrated that models like the RUSLE can be considered a useful tool to individuate changes of erosion rates and to isolate the effect of climate change on soil loss. Also, the opposite trend obtained for the annual rainfall measurements suggests that these should not be used to explore the effects of climate change in Mediterranean areas but measurements of rainfall at shorter time intervals (≤ 30 min) are necessary.