[H-CG20] 地球表層ダイナミクスの実験的研究

[HCG20-P03] Soil erosion by wind dust-emission and water-sediment runoff in a dryland

*Itzhak Katra¹、Smadar Tanner¹、Meni Ben-Hur² (1.Department of Geography and Environmental Development, Ben Gurion University, Be'er-Sheva, Israel、2.Institute of Soil, Water & Environmental Sciences, the Volcani Center, P.O. Box 15159, Rishon LeZion 7505101, Israel)

キーワード：Soil Aggregation, Sediment Flux, Soil Erodibility

Soil erosion is a significant process in the loss of soil/land resources, degradation and desertification. The increase land-use changes and the future projection for the increasing of soil-dust emissions and rainfall intensities, emphasize the need for a better understanding of soil erosion. Traditionally, wind and water erosions have been studied and modelled separately. However, semi-arid regions are subjected to both forces of erosion. A quantitative sediment flux based on direct measurement from a specific soil due to both water and wind erosion is lacking. The study aimed to drive such erosion rates in a semi-arid Loess soil (The Negev Desert, Israel) that is subjected to both forces of erosion. Soil samples from top-and sub-layers of the soil were analyzed for physical and chemical properties, including characteristics of soil aggregation. We performed targeted laboratory experiments using a boundary layer wind-tunnel for wind erosion and rainfall simulator for water erosion. Rates of sediment flux that were calculated for the topsoil and the subsoil revealed an opposite trend between water and wind erosion. This indicates that soil erodibility strongly depends on the erosional force applied rather than a certain soil property. The study conducted in a semi-arid region and may serve as a case study under climate change scenarios, in which more (non-arid) regions will be subjected to increase soil erosion.