摘要
为探明微润灌土壤湿润体特性的变化规律,以扰动均质土壤为研究对象,采用室内模拟试验的方法,分析了不同初始含水率(2.1%,5.6%,8.0%,10.1%)条件下微润灌土壤湿润锋运移距离和水分分布的变化规律.结果表明:土壤初始含水率对微润灌溉线源扩散有较大的影响,湿润锋推进速率、地表湿润时间随着初始含水率的增大而增大,并与灌水时间呈幂函数关系;湿润体形状受初始含水率影响非常小,其横断面为近似圆形;一定灌水时间内,累计入渗量、平均入渗率与初始含水率呈正相关性,且到达稳定入渗率的时间与初始含水率呈负相关性,湿润锋推进速率与初始含水率呈正相关关系,扩散系数与初始含水率成指数递增关系,不同初始含水率的不同方向土壤水分扩散指数介于0.50~0.60之间;湿润体内水分呈同心圆分布,含水率梯度随着初始含水率的增大而减小;微润灌均匀系数随初始含水率的增大而增大.研究结果可为微润灌溉技术推广应用提供理论依据.
In order to identify effects of soil initial water content on line-source infiltration characteristics in moistube irrigation,the wetting front advance distance and soil moisture variation feature were investigated through indoor simulation experiments for isotropic soil under four initial water contents: 2. 1%,5. 6%,8. 0% and 10. 1%. The experimental results revealed that soil initial water content had a great effect on line-source infiltration,the advance speed of wetting front and surface wetting time were raised and extended with increasing initial water content,and could be presented by a power function of irrigation time. Meanwhile,the shape of wetting soil was slightly affected by initial water content and its cross-section shape was kept to be nearly circular. During an irrigation event,the cumulative infiltration and average infiltration rate were positively correlated with initial water content, but the time for a stable infiltration rate was negatively related to the content. The water content inside a wetting soil body was distributed concentrically,and the moisture gradient was decreased with increasing initial water content,however,the uniformity coefficient of moistube-irrigation was increased with the content. Those results may be useful for application of moistube-irrigation.
出处
《排灌机械工程学报》
EI
北大核心
2014年第1期72-79,共8页
Journal of Drainage and Irrigation Machinery Engineering
基金
国家863计划项目(2011AA100705)
教育部
国家外专局111计划项目(B12007)
关键词
微润灌
初始含水率
线源
湿润锋
土壤水分
moistube-irrigation
initial water content
line-source
wetting front
soil moisture
