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Spatial and Temporal Evaluation of Soil Erosion with RUSLE: A Case Study in an Olive Orchard Microcathment in Spain
Citation:
Taguas, E. V., P. Cuadrado, J. L. Ayuso, Y. YUAN, AND R. Perez. Spatial and Temporal Evaluation of Soil Erosion with RUSLE: A Case Study in an Olive Orchard Microcathment in Spain. Presented at European Geosciences Union Assembly 2009, Vienna, AUSTRIA, April 19 - 24, 2009.
Impact/Purpose:
Poster Presentation materials
Description:
Soil loss is commonly estimated using the Revised Universal Soil Loss Equation (RUSLE). Since RUSLE is an empirically based soil loss model derived from surveys on plots, the high spatial and temporal variability of erosion in Mediterranean environments and scale effects provoke that studies evaluating the model on other spatial units such as the microcatchment are neceesary. Most of studies to check the suitability of the management operations in olive orchards have been done on plot scale, however, the microcachment is a geomorphological unit where hydrological processes are more numerous, do not occur isolatedly and whose area is well-adapted to the farmland small size and farmland medium size. In this study, different topographic and soil surveys have been carried out on a microcatchment of 6.7 ha in a mountainous area under non-tillage farming with bare soil to examine spatial and temporal results provided by RUSLE. Thus, the height difference of microrelief through GPS measurements has been set on a control area in the microcatment to compare erosion points and deposition points with RUSLE spatial predictions. In addition, measures of loads of sediments were taken out to calculate the annual sediment delivery ratio and the storage that determine the utility of RUSLE. Finally, data series of daily rainfall were acquired to calculate the long term erosion and to check the suitability of land-use and the management under different thresholds of tolerance. Erosion points were located on zones with the highest RUSLE values while the distribution of deposition points showed no correlations with RUSLE predictions. In addition, an annual sediment delivery ratio in the cachtment about 26 % was calculated (period 2005-06). Although substantial spatial differences were observed, mean erosion long term estimates in the catchment showed 35 % of years, soil loss may overpass 2 t.ha-1.year-1 and 7 % of them, erosion may be higher than 5 t.ha-1.year-1. On this study scale, RUSLE allowed to locate the most fragile areas and to combine the suitability of the soil land-use and the management with the frequency of the annual erosivity.