Statistical distribution of soil loss and sediment yield at Sparacia experimental area, Sicily

An analysis of the statistical distribution of event soil loss was carried out using the data collected in the period 1999–2008 at the microplots and plots of the Sparacia experimental area (Sicily, Italy). For a given microplot size, the analysis allowed to establish that the soil loss frequency distribution was skewed. Using the soil loss normalized by the event mean value, the analysis also showed that the frequency distributions corresponding to different microplot and plot sizes were overlapping, i.e. all distributions were extracted by the same statistical population. The developed analysis allowed to suggest that the soil loss of a given return period can be estimated using a scale and a frequency factor. Finally the sediment yield data collected in two basins of the Sparacia area were used to compare the frequency distributions of normalized soil erosion data collected at different spatial scales (plot, basin). The overlapping of the two distributions was satisfactory, and the conclusion was that the mean value of the measured variable is expressive of the characteristics of the sediment source area.