Interactive effects of rainfall intensity, kinetic energy and antecedent soil moisture regime on splash erosion in the Ultisol region of South China

Authors: WANG, LUN - Northwest A&f University; ZHENG, FENLI - Northwest A&f University; HU, WEI - China Institute Of Water Resources; Zhang, Xunchang; SHI, HONGQIANG - Northwest A&f University

Submitted to: Catena
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/9/2022
Publication Date: 3/1/2023
Citation: Wang, L., Zheng, F., Hu, W., Zhang, X.J., Shi, H. 2023. Interactive effects of rainfall intensity, kinetic energy and antecedent soil moisture regime on splash erosion in the Ultisol region of South China. Catena. 222(2023).Article 106863. https://doi.org/10.1016/j.catena.2022.106863.
DOI: https://doi.org/10.1016/j.catena.2022.106863

Interpretive Summary: Splash erosion by raindrop impact has been acknowledged as a key process of soil erosion, depending on multiple factors including rainfall properties, antecedent soil moisture, and surface runoff. Previous studies mostly focused on the effect of simple factor on splash erosion, but the interactive effects of multiple factors on splash erosion are still obscure. Therefore, this study investigated the characteristics of splash erosion and quantified the interactive effects of multiple factors on splash erosion using a modified splash pan for measuring directional splash erosion. The results showed that total splash erosion and net downslope splash erosion ranged from 14.4-804.8 g per square meter and 2.0-186.5 g per square meter, and increased with rainfall intensity and rainfall kinetic energy. Splash erosion rates in the dry run were greater than those in the wet run at the earlier stage; whereas, after runoff occurred, splash erosion rates in the dry run were lower than those in the wet run. This study provides useful information for soil conservationists and erosion modelers for understanding splash erosion mechanisms, controlling splash erosion by increasing surface cover, and improving process-based erosion models.

Technical Abstract: Splash erosion has been acknowledged as a key process of soil erosion, depending on multiple factors including rainfall properties, antecedent soil moisture, and surface runoff. Previous studies mostly focused on the effect of simple factor on splash erosion, but the interactive effects of multiple factors on splash erosion are still obscure. Therefore, this study investigated the characteristics of splash erosion and quantified the interactive effects of multiple factors on splash erosion using a modified splash pan for measuring directional splash erosion. The results showed that total splash erosion (summation of four directional splash erosion) and net splash erosion (downslope minus upslope splash erosion) ranged from 14.4-804.8 g per square meter and 2.0-186.5 g per square meter, and increased with rainfall intensity and rainfall kinetic energy. Splash erosion rates in the dry run were greater than those in the wet run at the earlier stage; whereas, after runoff occurred, splash erosion rates in the dry run were lower than those in the wet run. Furthermore, the calculated variance contributions indicated that before runoff occurrence rainfall kinetic energy (KE) and antecedent soil moisture were the dominant factors affecting splash erosion, accounting for 25.3% and 15.0% of variance contributions, respectively. After runoff occurrence, the main factors affecting splash erosion were rainfall intensity (RI), rainfall kinetic energy (KE) and their interactions, explaining 98.2% of the total splash and 95.7% of the net splash for all variance contributions. In addition, the effect of shallow flow on splash erosion was dependent on the ratio of flow depth and raindrop diameter (h/D). The thresholds of h/D seemingly ranged from 0.63 to 0.86 and 0.77 to 1.02 for the dry and wet runs under 100 mm/h rainfall intensity. This study provides a basis for understanding splash erosion mechanisms and improving process-based erosion models.