State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China; State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu 610065, China.
State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing 210029, China; Chuzhou Scientific Hydrology Laboratory, Nanjing Hydraulic Research Institute, Chuzhou 239080, China; Yangtze Institute for Conservation and Development, Nanjing 210098, China.
J Contam Hydrol. 2022 Jun;248:104022. doi: 10.1016/j.jconhyd.2022.104022. Epub 2022 May 10.
Knowledge of soil water content (SWC) dynamics within soil profiles is crucial for the effective management of water and soil resources. This study aims to clarify the temporal variability and stability of SWC in a forested critical-zone experimental catchment, and further to improve the understanding of the temporal and spatial distribution of soil water in a typical hilly catchment in eastern China. The selected Nandadish (NDD) catchment covering 0.79 ha was instrumented with 34 SWC monitoring sites using Frequency Domain Reflectometry. The consecutive high-resolution monitoring data of soil water at different depths of the sites were collected from January 2017 to December 2019. The results showed that the SWC of the shallow layer (0-30 cm) had the strongest variability over time during the three hydrologic years. The interannual variability of SWC showed the opposite regularity with that of the seasonal variability. Specifically, the spatial variability of SWC in the dry years was greater than that in wet years; whilst the temporal stability of SWC in dry seasons was greater than that in rainy seasons. Precipitation and temperature were the two dominant factors influencing the temporal variation of SWC. Precipitation controlled the interannual variation of SWC, while temperature controlled the seasonal variation of SWC. Additionally, soil water had high temporal stability throughout the observation period in NDD catchment, and the most representative point was located at a relatively flat and central place, which can be used to simulate the variability of SWC under different rainfall conditions in the study area. The temporal stability of SWC patterns was controlled by topography, geographic location, throughfall, and the groundwater level in the study area, which was characterized by sloping terrain and forested cover. This research provides scientific bases for the optimum design of ground sampling, and the temporal and spatial prediction for soil moisture in a typical eastern hilly area with forest land uses.
土壤剖面中土壤水分含量（SWC）动态的知识对于有效管理水和土壤资源至关重要。本研究旨在阐明森林临界区实验流域中 SWC 的时间变化和稳定性，并进一步提高对中国东部典型丘陵流域土壤水分时空分布的认识。选择了覆盖 0.79 公顷的 Nandadish（NDD）流域，使用频域反射计在 34 个 SWC 监测点进行了仪器安装。从 2017 年 1 月到 2019 年 12 月，在这些站点的不同深度连续采集了高分辨率的土壤水分监测数据。结果表明，在三个水文年期间，浅层（0-30cm）的 SWC 时间变化最强。SWC 的年际变化规律与季节性变化规律相反。具体来说，干旱年份的 SWC 空间变异性大于湿润年份；而干旱季节 SWC 的时间稳定性大于雨季。降水和温度是影响 SWC 时间变化的两个主要因素。降水控制着 SWC 的年际变化，而温度控制着 SWC 的季节性变化。此外，在 NDD 流域的整个观测期间，土壤水分具有较高的时间稳定性，最具代表性的点位于相对平坦和中心的位置，可以用来模拟研究区域不同降雨条件下 SWC 的变化。SWC 模式的时间稳定性受地形、地理位置、穿透雨和研究区域地下水位的控制，其特点是地形陡峭，森林覆盖。这项研究为地面采样的最佳设计和森林用地典型东部丘陵地区土壤水分的时空预测提供了科学依据。
