Effects of Rainfall Properties and Soil Structure on Raindrop Splash Erosion

Abstract

Rainfall and soil are key factors affecting raindrop splash erosion. Extensive efforts have been made toquantify effects of rainfall and soil properties on raindrop splash erosion and study mechanisms of raindropsplash. However, there are few available data to quantify effects of soil structure on raindrop splash erosion,especially in the Loess Plateau of China. A laboratory study was designed to quantify effects of rainfallproperties and soil structure on raindrop splash erosion. Splash pans, consisting of an inner-cylinder with 10-cm-diameter and 2.5-cm-high, and a boundary wall with 30-cm-diameter and 10-cm-high, were used in thisstudy. The experimental variables included five rainfall intensities: 35, 50, 70, 90 and 120 mm h-1, oneundisturbed soil and four disturbed soils. The results showed that the relationship between raindrop splasherosion and rainfall intensity was best described as an exponential function. Raindrop splash erosion wasclosely related to the product (Ed50) of raindrop kinetic energy (E) and raindrop size (d50). The splash erosionwas increased with rainfall duration; however, splash detachment rate was decreased with rainfall duration. Thesplash erosion from undisturbed soil was decreased by 70 to 88% under different rainfall intensities, ascompared to disturbed soil. These results show that it is important to focus on understanding the effects of theinteraction between raindrop kinetic energy and raindrop size on raindrop splash erosion, and quantifying soilstructure effects on the erosion process.