Splash drift on light sandy soils: a field experiment

Vertical splash drift profiles and horizontal splash drift amounts were measured during a very wet week on a 7.5 ha agricultural field in Gronheim, Germany. Splash was measured on 45 plots distributed all over the field, at seven (Or eight) heights above the surface. The data show that the vertical splash drift profile is best described by a power function of the form G = a.z(b) (or, alternatively, G = c.z(b) - 1), where G is the total mass of sediment splashed up to a height z and a, b and c are empirical parameters. The decrease of G with height z is highly variable within the field, even for one and the same rain shower. Also, the total horizontal splash drift amounts show significant differences within the field. There is no clear relationship between these splash characteristics on the one hand and the topographic position or the properties of the topsoil on the other. It is suggested that spatial variations in rainfall during the rain events are the major cause of the differences in splash drift over the field. Total horizontal splash flux is fairly well predicted by a theoretical splash transport model developed earlier by the second author. Due to the effect of the wind (causing oblique rainfall and an extra-displacement of the soil particles in the downwind direction) the observed fluxes are somewhat higher than the predicted ones, but both are of the same order. The difference indicates the significance of the inclination of the rain with respect to the process of hydraulic splash.