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| DOI：10.13522/j.cnki.ggps.2020055 |
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| Tracing Water Infiltration in Soils with Isotopes in the Yongning Irrigation District in the Yellow River Basin |
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ZHAO Zhipeng, YANG Lihu, GONG Liang , LI Bingliang, MA Xuedong , XU Yingchun, LIU Haiyan
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1.Geological Bureau of Ningxia Hui Autonomous Region, Yinchuan 750021, China; 2. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; 3. Sino-Danish College, University of Chinese Academy of Sciences, Beijing 101400, China; 4.Ningxia Geological Survey Institute, Yinchuan 750021, China; 5. School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China
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| Abstract: |
| 【Background】Rainfall and irrigation are two factors mediating water movement in soil, but how the exogenous water percolates in soil remains elusive.【Objective】We took Yinchuan plain in the Yellow river basin of China as an example, tracing water infiltration in soil using isotopes in attempts to help improve agricultural water management in this region.【Method】We observed and analyzed in 2019 isotope contents in rainfall, irrigation water, soil water and groundwater in this region.【Result】The overall rainfall from April to October was 157.3 mm, with maximum rain falling in July which accounted for 55% of the annual precipitation. Most rainfalls were small to moderate. The maximum δD and δ18O concentrations decreased downwards along the soil profile, and the standard deviation of the isotope concentrations in water in the top 0~50 cm soil was higher than that in the subsoil. Precipitation falling on 7 May, 25 June and 28 June contributed 13.7%, 14.8% and 83.9% to the water in the top 0~50 cm of soil, respectively. On average, irrigation water contributed 49.3%~100.0% to the water in the top 0~50 cm of soil, and 14.3%~46.6% to the water in soil below the depth of 70 cm.【Conclusion】 The rainfall infiltrated into the soil to a depth of 30~50 cm depending on rainfall intensity, while irrigation water could percolate as deep as 270 cm. Evaporation was mainly from the water in the top 0~50 cm of soil. |
| Key words: unsaturated zone; soil water; hydrogen and oxygen isotopes; soil water movement; Yinchuan plain |
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