Effects of rainfall intensity and kinetic energy on hillslope soil erosion in the thin-layer Mollisol region of China: Field observation and rainfall simulation

Le résumé fourni par la source

Rainfall kinetic energy ( KE ) is a critical factor influencing the early-stage dispersion of soil particles caused by raindrop impact during water erosion. However, the effects of rainfall intensity and the KE on hillslope soil erosion and the relationships between rainfall intensity and the KE under natural and simulated rainfall conditions need to be further investigated. This study combines field observations with simulated experiments to explore the relationship between rainfall intensity and the KE , as well as their impacts on hillslope soil erosion in Chinese Mollisol regions. The results reveal that natural erosive rainfall can be categorized into three distinct patterns of P1 (low KE and long duration), P2 (medium KE and short duration) and P3 (high KE and short duration). Among these, the extreme rainfall pattern of P3 was identified as the primary driver of severe hillslope soil erosion. This pattern of erosive rainfall constituted 34.3% of all erosive rainfall events observed in the field and was responsible for more than 81.3% of the total soil loss. Under simulated rainfall conditions, when the rainfall intensity increased from 50 mm h -1 to 100 mm h -1 , the KE increased by 1.4-1.9 times, and the soil erosion rates increased by 1.6-2.1 times. Additionally, with the increase in KE under the same rainfall intensity, hillslope soil erosion increased by 1.2-1.8 times at a rainfall intensity of 50 mm h -1 and by 1.5-2.1 times at a rainfall intensity of 100 mm h -1 . This study underscores the importance of considering the KE in the design and application of rainfall simulation experiments for erosion studies. • Empirical formulas may overestimate the kinetic energy compared to measurements by Laser Precipitation Monitor. • Soil erosion increases exponentially with kinetic energy under both natural and simulated rainfall conditions. • Hillslope soil erosion under the same kinetic energy may vary greatly due to different rainfall patterns.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.