XIE Jinyan¹, SUN Fangqiang², ZOU Lirong³, QI Jiahua¹

（1. School of Geology and Environment, Xi 'an University of Science and Technology, Xi'an 710054, China;
2.Arid and Semi-arid Region Ground Water and Ecology Key Laboratory, Xi’an Center, China Geological Survey, Xi'an 710054, China;
3.Changqing Oilfield Third Gas Extraction Factory, Xi 'an 710018, China）

Abstract: The isotope tracing technique is applied in the study of source and migration mechanism of soil water in Xiekou town of Lintong in Shaanxi province. In the study area, four soil profiles with varying land use types were selected to collect the soil water and to analyze the isotope signals of δD and δ18O. The vertical variation of isotope signals was analyzed in the unsaturated zone. The results show that soil water in the unsaturated zone undergoes obvious mixing during the infiltration, and can be divided into three layers in the vertical direction. The δD value of recharge water in this zone is within the range of -75‰~-60‰, which lies between the atmospheric precipitation and the groundwater. This study indicates the recharge of the subsoil water comes from the groundwater, while the topsoil water comes from the atmospheric precipitation and the irrigation water.

Key words: soil water; hydrogen and oxygen isotopes; recharge sources

EARTH AND ENVIRONMENT Vol.48, No.6, Tot No.338, 2020, Page 728-735