SOIL HYDROPHOBICITY EFFECTS ON RAINSPLASH - SIMULATED RAINFALL AND PHOTOGRAPHIC EVIDENCE

Laboratory rainfall simulation experiments indicate greater splash los ses for hydrophobic (water repellent) than for wettable sandy loam soi ls at different rainfall intensities, durations and soil surface incli nations. Using synchronized video cameras with different shutter speed s and stroboscopically illuminated 35 mm still photography, difference s in splash droplets and ejection trajectory characteristics are exami ned. For hydrophobic soil, raindrop impact gives rise to fewer, larger , slower-moving daughter ejection droplets which carry more sediment a nd hence follow shorter range trajectories compared with wettable soil . Implications for erosion of hydrophobic soils are discussed.