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

Adane Zablon A, Lincoln NE

Investigators

Abstract

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.