Subjects: Geosciences >> Hydrology submitted time 2023-03-28 Cooperative journals: 《干旱区研究》
Abstract： River canal leakage is the main mode of surface water replenishment to soil water for desert riverbank ecological protection, plant water absorption, and utilization. It is also an important cause of soil salinization during increased groundwater level periods. Therefore, studying the movement of groundwater and soil moisture under the condition of canal leakage recharge in arid areas can be crucial not only for constructing a benign ecological circulation system dominated by water environment, but also for preventing soil salinization. This study used laboratory simulation experiment to analyze the capillary water movement characteristics in loamy sand under different water levels in Yarkant River irrigation area. Results showed a decreasing trend in the capillary water supply rate, which could be subdivided into three stages, including rapid decrease, linear decrease, and stable- state, while the average stable recharge rate 0.02 mm · min- 1 was detected. The rising height of capillary water and rising rate both had parabola relationships with the recharge time. Validation of the linear relationship between capillary water recharge and rising height of capillary water under different canal water levels revealed that the slope (B) was equal to the difference between the mean soil water content (θmean) and initial water content (θi), while B values under different canal water levels ranged from 0.3155 to 0.4046 cm3·cm-3, with a mean value of 0.3695 cm3 ·cm- 3. A linear correlation was detected between capillary water supply rate and the reciprocal value of rising height of capillary water. The improved Green-Ampt model could successfully be used to simulate capillary water rise process in a homogeneous loamy sand. Overall, these results could potentially provide clues for studying the restoration and reconstruction of ecologically protected plants in canals, and for the prevention of soil salinization in arid areas.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2020-11-20 Cooperative journals: 《干旱区地理》
Abstract：为确定古尔班通古特沙漠南缘地下水深埋区毛管上升水的最大上升高度，对划分固沙植物水分来源提供理论依据，于2016年3月～2018年11月，采用中子仪法对试验地0～10 m土层土壤含水量进行观测，分析沙丘不同坡位土壤含水量的季节变化情况，并利用最大分子持水量与土壤含水量曲线交会法确定试验地毛管水的最大上升高度。结果表明：沙丘不同坡位0～130 cm土层的土壤含水量受外界气象因素影响较大，随季节变化规律明显；130 cm土层以下至570～760 cm土层为土壤含水量较为稳定的干沙层；而570～760 cm以下土层的土壤含水量主要受地下水水位波动和毛管上升水的影响，其含水量变化上界可看作是毛管水的最大上升高度。试验地的最大分子持水量为0.026 1 cm3·cm-3，且沙丘不同坡位毛管水的最大上升高度分布在250～290 cm之间。
Subjects: Geosciences >> Other Disciplines of Geosciences submitted time 2018-11-14 Cooperative journals: 《干旱区地理》
Abstract： 根据2016年古尔班通古特沙漠南缘丘间地梭梭生育期定点观测的土壤水分、气象要素等资料，基于水量平衡原理估算了梭梭生育期蒸散量，分析了蒸散变化规律。结果表明：（1）在梭梭生长季，降雨量为206.7 mm，降雨分布不均，梭梭萌发期，降雨量最多；梭梭生长旺盛期，月降雨量逐月减少；梭梭枯落期，降雨量最少；（2）在梭梭生长季，梭梭群落0~400 cm土壤贮水量变化整体呈下降趋势, 梭梭萌发期是土壤贮水量盈余期，生长旺盛期和枯落期为土壤贮水量亏损期；梭梭群落发挥土壤水库效应，依靠生长季前土壤蓄水来弥补梭梭群落生长季需水缺额；（3）在梭梭生长季，蒸散量变化特征为多峰曲线，峰值主要出现在降雨集中期，最低值出现在土壤贮水量亏损期；（4）在梭梭生长季，梭梭群落累积蒸散量增幅始终高于累积降雨量增幅，累积蒸散量大于累积降雨量。
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