Comparative measurements with seven rainfall simulators on uniform bare fallow land

Iserloh, T.; Ries, J.B.; Cerda, A.; Echeverria, M.T.; Fister, W.; Geissler, C.; Kuhn, N.J.; Leon, F.J.; Peters, P.; Schindewolf, M.; Schmidt, J.; Scholten, T.; Seeger, K.M.


To assess the influence of rainfall simulator type and plot dimensions on runoff and erosion, seven small portable rainfall simulators from Freiberg, Tubingen, Trier (all Germany), Valencia, Zaragoza (both Spain), Basel (Switzerland) and Wageningen (the Netherlands) were compared on a prepared bare fallow field. The experiments were carried out during an international rainfall simulator workshop, organized at Trier University (Germany) from 30th of June to 1st of July 2011. The tested rainfall simulators differ in design, rainfall intensities, rain spectra, etc. and represent most of the devices which have been used over the last decade in Europe. The plots for the different rainfall simulators were selected as similar as possible concerning soil physical and chemical properties, aspect and inclination and were chosen to be placed side by side in horizontal direction. Test procedure was standardized in order to examine the influence of the rainfall simulator and plot dimension only. The results show a clear and consistent relationship in runoff, erosion and infiltration behaviour of the different used rainfall simulators. With all the devices total soil loss is measurable, but different plot sizes, intensities and kinetic energies of the simulated rainfall caused differences in soil loss and runoff quantities per unit of area. Regarding course characteristics over runs, similarities could be observed especially in runoff behaviour. The rainfall simulators (= 1 m(2)), rill-erosion will be also reflected. Therefore it can be concluded that up to a certain plot size, the results of the different simulators are comparable and depend in their magnitude on the properties of the applied rainfall. The increase in process complexity with increasing plot size shows, that the scale of the simulation is one of the most important parameters to be taken into account when comparing values of erosion and runoff.