| 引用本文: | 韩 星,潘英华,陈小兵,等.基于土柱模拟试验的盐渍土剖面盐分
聚集特征及机理研究[J].灌溉排水学报,2025,44(11):80-89. |
| HAN Xing,PAN Yinghua,CHEN Xiaobing,et al.基于土柱模拟试验的盐渍土剖面盐分
聚集特征及机理研究[J].灌溉排水学报,2025,44(11):80-89. |
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| 摘要: |
| 【目的】探究黄河三角洲盐渍化土壤剖面盐分表层聚集特征及机理。【方法】以黄河三角洲地区重度盐渍土（砂质黏壤土，平均含盐量为37.24 g/kg）为研究对象，在室内进行一维垂直土柱吸渗试验，设置3个地下水矿化度（K1、K2、K3分别为0、5、10 g/L）和3个地下水埋深（S1、S2、S3分别为10、30、50 cm），共9个处理，分析地下水矿化度和地下水埋深对土壤毛管水上升高度、湿润锋运移速率、累积吸渗量动态、土壤剖面水盐分布以及盐分聚集的影响。【结果】①同一地下水埋深下，地下水矿化度对毛管水上升高度、速率、累积吸渗量及土壤体积含水率的影响不显著。随着地下水埋深的增加，湿润锋到达地表时间增加，累积吸渗量增大，表层土壤体积含水率降低。②地下水埋深相同时，不同地下水矿化度处理土壤剖面下部土壤含盐量差异显著（p＜0.05），上部土层土壤含盐量差异较小。不同地下水埋深处理土壤剖面盐分均呈表层聚集现象，其中脱盐区占比超过60%，且积盐区范围随地下水埋深增加而扩大。③当毛管水上升至表层土壤时，相同地下水埋深不同地下水矿化度处理土壤剖面体积含水率和土壤含盐量变化曲线拐点一致，S1、S2、S3处理对应拐点分别位于4~6、16~18、26~28 cm土层，且在这些拐点之上，土壤体积含水率和土壤含盐量显著线性相关（p＜0.05）。【结论】在蒸发作用较弱的条件下，剖面盐分表聚主要由毛管力驱动的水分运移主导，并受盐分溶解、扩散与吸附动态平衡的调控。 |
| 关键词: 盐渍土；毛管水；湿润锋；盐分表聚 |
| DOI：10.13522/j.cnki.ggps.2025063 |
| 分类号: |
| 基金项目: |
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| Salt accumulation and its controlling factors in saline soil profile of Yellow River Delta |
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HAN Xing, PAN Yinghua, CHEN Xiaobing, DONG Xiaoyan, SUN Kaixiao
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1. School of Resources and Environmental Engineering, LuDong University, Yantai 264025, China;
2. Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China
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| Abstract: |
| 【Objective】Soil salinization is a major threat to agricultural productivity in the Yellow River Delta, where shallow groundwater and high soil salinity often result in salt accumulation in the root zone. This paper experimentally investigates the mechanisms underlying salt accumulation in this region.【Method】The experiment was conducted using soil columns packed with clay loam with a salt content of 37.24 g/kg taken from the Yellow River Delta. It compared nine treatments, in which the salt content of the groundwater was 0 (K1), 5 (K2) and 10 g/L (K3), and the groundwater table was controlled at the depths of 10 (S1), 30 (S2) and 50 cm (S3). For each treatment, we measured the capillary rise of groundwater, groundwater uptake rate, cumulative groundwater uptake, and water-salt distribution in the soil profiles.【Result】① When the groundwater table depth was the same, groundwater salt content had no significant effect on the height of capillary water rise, groundwater uptake rate, cumulative groundwater uptake, and volumetric soil water content. Increasing groundwater table depth delayed the advancement of the wetting front, increased the cumulative groundwater uptake, and decreased the topsoil water content. ② When the groundwater table depth was the same, there was a significant difference in salt content in the lower part of the soil profile between different groundwater salt contents (p＜0.05), but not in the upper part of the soil profiles. Regardless of groundwater table depth, salt accumulated in the soil surface in all treatments. Over 60% of the soil profiles comprised desalinated zones, with the salinized zone increasing as the groundwater tables increased. ③ After the groundwater reached the soil surface via capillary rise, the inflection points in the distribution of soil water and salt along the soil profile were the same when the groundwater table depth was the same, located at the depth of 4-6 cm, 16-18 cm and 26-28 cm for S1, S2 and S2, respectively. Above these critical locations, soil volumetric water content and soil salinity were linearly correlated (p＜0.05).【Conclusion】When soil evaporation was weak, salt accumulation in the soil surface was primarily driven by capillary rise of groundwater and modulated by the dynamic equilibrium between salt dissolution, diffusion and adsorption in the soil profiles. |
| Key words: saline soil; capillary water; wetting front; surface salt accumulation |
