[目的] 探讨乌兰布和沙漠白刺灌丛沙堆丘间地黏土层土壤水分时空格局及其对降雨变化的响应，为准确评估丘间地在白刺灌丛沙堆土壤水分循环和保持土壤水分稳定性的作用提供科学依据和数据支撑。 [方法] 采用EM50土壤水分自动测量系统对丘间地黏土层土壤水分进行长期原位监测，分析不同降雨条件下丘间地土壤水分空间格局和时间动态，定量描述降雨量、雨前土壤水分含量与丘间地黏土层土壤水分入渗和保持时间的关系。 [结果] ①从丘间地黏土层土壤水分空间变异特征来看，0-25 cm土层土壤水分的变异程度均为中度变异，其中表层(0-15 cm)变异性较大，下层(15 cm以下)变异性较小。 ②降雨量的大小决定了降雨后丘间地土壤水分入渗深度和保持时间，降雨量平均每增加1 mm，丘间地黏土层土壤水分下渗深度增加0.57 cm，土壤水分保持时间增加1.05 d。雨前土壤水分含量过高抑制丘间地黏土层土壤水分的继续下渗，但对降雨后丘间地黏土层土壤水分保持时间有显著的正效应，表现为雨前土壤水分含量每增加1%，单位降雨量的下渗深度下降0.02 cm，而丘间地黏土层土壤水分保持时间增加9.85 d。 ③大雨事件(＞20 mm)对丘间地黏土层土壤水分具有明显的补给作用，降雨后土壤水分降低较为缓慢。 [结论] 丘间地黏土层能够抑制土壤水分蒸发，具有较好的蓄水保水效应。
[Objective] The the spatial-temporal patterns of soil water at the inter-dune area of Nitraria tangutorum nebkhas and its response to rainfall changes were determined in order to provide a scientific basis and data support for the accurate assessment of the role of inter-dunes in the soil water cycle and soil water stability in Nitraria tangutorum nebkhas. [Methods] The EM50 automated soil moisture measurement system was used to acquire long-term in-situ measurements of soil moisture in the clay layer of the inter-dune area. We analyzed the spatial patterns and temporal dynamics of soil water in the inter-dune soils under different rainfall conditions, quantifying the relationship between rainfall, soil water content before rainfall, and soil water infiltration and retention time in the inter-dune clay layer. [Results] ① From the perspective of the spatial variation characteristics of soil water in the clay layer, the variation degree of soil water in the 0-25 cm soil layer was characterized as moderate variation, among which the surface layer (0-15 cm) had greater variability and the lower layer (below 15 cm) had less variability. ② The magnitude of rainfall determined the infiltration depth and retention time of soil water at the inter-dune area after rainfall. As the average rainfall increased by 1 mm, the infiltration depth of soil water in the clay layer increased by 0.57 cm, and the soil water retention time increased by 1.05 days. Excessive soil water content before a rainfall event inhibited the continuous infiltration of soil water in the clay layer, but had a significant positive effect on soil water retention time after the rainfall, as shown by a 1% increase in soil water content before a rainfall event, and a 0.02 cm decrease in infiltration depth per unit rainfall, while the soil water retention time of the clay layer increased by 9.85 days. ③ Heavy rainfall events (＞20 mm) had an obvious replenishment effect on soil water in the clay layer, and the soil water decreased slowly after rainfall. [Conclusion] The inter-dune clay layer can inhibit soil water evaporation and provide good water storage and water retention.