THE EFFECT OF SOIL TYPE, SLOPE, RAIN INTENSITY AND THEIR INTERACTIONS ON SPLASH DETACHMENT AND TRANSPORT

From a factorial experiment using a graded sand and three soils (sand, clay loam, and clay), five slopes (0.0, 3.5, 7.0, and 14.0 per cent) and four intensities (50, 80, 110, and 140 mm h^?1), splash detachment and splash transport are described in terms of the direct effects and the first and second order interactions of these variables. The graded sand and three soils tested are significantly different in the mean weight of soil detached and transported. They can be placed in rank order of graded sand, sand, clay, and clay loam with increasing resistance to splash detachment. The amount of material transported is in the order of graded sand > clay > sand > clay loam. For each soil there are significant increases in splash detachment and splash transport with increasing rainfall intensity. Both splash parameters are significantly correlated with slope steepness. The most important interactions that influence splash detachment and splash transport are soil × intensity and slope × intensity respectively. Significant interactions show that the factors are not independent of each other; the simple effects of a factor differ, and the magnitude of any simple effect varies according to the level of the other factors of the interaction term. These interactions have not been explicitly studied in previous research on splash erosion. Power equations are established between splash activity and the above variables and reasonable working ranges for the exponents are suggested.