蓄水坑灌水土温度变化对土壤水分再分布规律的影响  

Impact of Temperature on Soil Water Distribution under Irrigation from a Water Storage Pit

作　　者：任荣[1] 马娟娟[1] 郑利剑 程奇云[1] 郭向红[1] 孙西欢[1,2] REN Rong;MA Juanjuan;ZHENG Lijian;CHENG Qiyun;GUO Xianghong;SUN Xihuan(College of Water Resource Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China;Jinzhong University, Jinzhong 030619, China)

机构地区：[1]太原理工大学水利科学与工程学院,太原030024 [2]晋中学院,山西晋中030619

出　　处：《灌溉排水学报》2018年第4期39-46,共8页Journal of Irrigation and Drainage

基　　金：国家自然科学基金项目(51579168);山西省自然科学基金项目(201601D011053);山西省科技攻关项目(20140311016-6)

摘　　要：【目的】探寻蓄水坑灌下土壤水分分布规律。【方法】通过构建蓄水单坑灌施条件下的物理模型,分别对恒定水温(15℃)不同土壤温度(15、20和30℃)和恒定土温(30℃)不同灌水温度(15、20和30℃)条件下的土体湿润锋和含水率进行了研究,并对恒定水温(15℃)不同土壤温度(15、20和30℃)条件下土体中水分的再分布进行了数值模拟。【结果】恒定水温时,在灌溉后的同一时刻,随着土壤温度的升高,湿润锋的径向和垂向推进距离的增量分别为18%和4.4%;恒定土温时,在灌溉后的同一时刻,随着灌水温度的升高,湿润锋的径向和垂向推进距离的增量分别为2%和1%,但在同一处理条件下,随着时间的推移,其平均推进速度在降低;在土壤水分的再分布过程中,土壤含水率的高值区域在临近水室的中下部位,随着土壤温度和灌水温度的增加,土壤含水率的高值区域呈现出扩大的趋势。在采用数值模拟的方法研究土壤水分再分布的运动规律时,土壤温度的变化对模拟计算的精度有较大的影响,尤其是土壤温度和灌水温度差异较大时,该影响更为明显,水土温度相差15℃时,模拟计算值和实测值之间的最大相对误差可达19.87%;文中给出了考虑不同土壤温度和灌水温度条件下的水分再分布修正因子,运用该修正模型,可将模拟计算值和实测值之间的最大相对误差减小至4.76%。【结论】蓄水坑灌下土壤水分再分布对土壤温度的变化较为敏感,文中修正模型可作为进一步精确模拟蓄水单坑灌施条件下土壤水分运动的有效工具。【Objective】Water storage pit is a technique used in arid and semi-arid regions to save rainfall for reuse. This paper investigated the impact of temperature on soil moisture distribution under irrigation from a water storage pit.【Method】An apparatus was constructed to experimentally study water movement under irrigation from a water storage pit. During the experiment, we measured the wetting front and water content distribution.Different temperature combinations were examined. One was to keep the irrigation water temperature at 15 ℃and vary soil temperature from 15 ℃ to 30 ℃, and the second one was to keep the soil temperature at 30 ℃ and vary the irrigation water temperature from 15 ℃ to 30 ℃. We also numerically simulated the redistribution of soil moisture when the irrigation water temperature was 15 ℃ and the soil temperature varied from 15 ℃ to30 ℃.【Result】When the irrigation water temperature was a constant, the advancing distance of the wetting front in the radial and vertical directions increased by 18% and 4.4%, respectively, as the soil temperature increased. When the soil temperature was constant, the advancing distance of the wetting front in the radial and vertical directions increased by 2% and 1%, respectively, as the irrigation water temperature increased. The water content in the area beneath and adjacent the pit was high and as the temperature increased, this areas expanded.The accuracy of the simulated results depends on soil temperature, especially when the soil and irrigation water temperatures were contrasting. The maximum relative error between the simulated and measured values was as high as 19.87% when their temperature difference was 15 ℃. To ameliorate this, we proposed a modified method which can reduce the error by 4.76%.【Conclusion】Under irrigation from a single water storage pit, soil moisture redistribution was sensitive to temperature change in soil, and the model proposed in this paper could be used to predict how the water moves from the pit t

关 键 词：土壤温度 灌水温度 水分再分布 数值模拟 蓄水坑灌 

分 类 号：S275.2[农业科学—农业水土工程]