Soil deformation after one water-drop impact – The effect of texture and soil moisture content

The splash phenomenon (being the first stage of water erosion) is caused by the drops’ impact on the soil surface, resulting in the displacement of soil particles and the creation of a deformation – a small-sized crater. The aim of this research was to analyse the effect of the drops' impact energy, the initial moisture content, and the texture of the soils used (loamy sand, sandy loam, silty loam) on the size of the formed craters. Measurements were made using a 3D surface scanner to determine the depth and volume of craters along with the equivalent diameter and circularity of their top cross-sections. In each of the experiment variants, the impact of the drops resulted in changes on the soil surface. Moisture content was the factor with the highest influence on crater formation (increase in moisture resulted in an increase in the size of the craters). The highest circularity was observed in craters formed on silty loam, which had the largest amount of silt content among the investigated soils. Increasing the drop energy resulted in an increase in the average values of the measured quantities, but only in a few cases were these changes statistically significant. The conducted research demonstrates the utility of surface scanners in accurately measuring soil deformation after drop impact. In addition, the acquired results can support the development of erosion models, increase the knowledge regarding the splash phenomenon, and help to make further steps in linking the splash to subsequent stages of water erosion.