EAPSI: Investigating the role of soil hydrophobicity on groundwater recharge beneath differing land uses in China's Loess Plateau

以前对黄土高原的研究发现，乔木和灌木种植园减少了黄土高原的地下水补给。虽然这些研究假设减少的补给量仅仅是由于较高的蒸腾和降雨截留，但其他研究表明，土壤疏水性与美国北部高平原地区人工林下减少的入渗和补给量之间的联系，也可能适用于中国的黄土高原。该项目与地质与地球物理研究所的庞忠革博士和黄天明博士合作，旨在研究不同土地利用方式下表层沉积物的疏水性，以确定疏水性在黄土高原减少补给中的作用。此外，这项研究将有助于确定人工林诱导的土壤疏水性是否是高平原地区独有的现象。建议的方法包括新的和传统的方法，包括表面入渗试验、深度为5厘米的沉积物上的乙醇水滴渗透试验，以及确定土壤水力参数的水分保持曲线。利用已经进行的详细的补给研究，该项目将检查疏水土壤、种植园类型和以前观察到的数据中的补给率。此外，拟议的研究将确定每个土地利用地块的土壤疏水性程度作为土壤水分含量、有机碳含量和剖面深度的函数。该NSF EAPSI奖是与中国科技部合作资助的。

Previous studies in the Loess Plateau have found that tree and shrub plantations have reduced groundwater recharge in the Loess Plateau. Whereas these studies have assumed that the reduced recharge is solely due to higher transpiration and rainfall interception, other studies suggested a link between soil hydrophobicity and reduced infiltration and recharge beneath plantations in the northern High Plains region of the United States that may also be applicable in China's Loess Plateau. In collaboration with Dr. Zhonge Pang and Dr. Tianming Huang at the Institute of Geology and Geophysics, this project aims to investigate hydrophobicity of near-surface sediments beneath differing land uses in order to determine the role of hydrophobicity on reduced recharge in the Loess Plateau. Further, the study will help determine whether plantation induced soil hydrophobicity is a phenomenon unique to the High Plains region.The proposed methods include new and traditional approaches including surface infiltration tests, ethanol water drop penetration tests on sediments up to 50 cm profile depth with 5 cm depth intervals, and water retention curves to determine soil hydraulic parameters. Leveraging detailed recharge studies that have already taken place, this project will examine patterns amongst hydrophobic soils, plantation types, and recharge rates from previously-observed data. In addition, the proposed study will determine the extent of soil hydrophobicity in each land use plot as a function of soil moisture content, organic carbon content, and profile depth. This NSF EAPSI award is funded in collaboration with the Chinese Ministry of Science and Technology.