埋深与压力对微润灌湿润体水分运移的影响

Effects of Buried Depth and Pressure Head on Water Movement of Wetted Soil during Moistube-irrigation

为探明微润灌土壤湿润体特性，设置5个不同埋深，6个不同压力水头，通过室内土箱试验研究了微润灌土壤水分运动规律。结果表明：压力水头是决定微润灌流量的重要因素；微润带埋深显著影响土壤湿润体的形状，湿润锋水平运移距离与宽深比γ均随埋深的增大而减小，垂直运移距离随埋深的增大而略微增大；土壤累计入渗量与埋深呈负相关关系；累计入渗量随灌水时间的变化过程符合Kostiakov人渗模型，建立了不同埋深累计入渗量预测模型，并用实测值进行了验证，实测值与预测值具有较高的相关性；土壤湿润均匀系数与埋深呈正相关，粘壤土微润灌最适埋深为15—20cm。

In order to research the characteristics of wetted soil under miostube-irrigation, five different buried depths and six different pressure heads were designed to investigate soil water movement through indoor soil box experiments. The results revealed that the pressure was the key factor to decide the miostube-irrigation flow, and the buried depths of miostube-belt had significant effect on the shape of wetted soil. The horizontal migration distance and ratio of width to depth of γ decreased with the increase of buried depths and vertical migration distance slightly increased with the increase of buried depths. There was a negative correlation between cumulative infiltration and buried depths and changing process of infiltration with irrigation time was accorded with Kostiakov infiltration model. The simulation model of cumulative infiltration under different buried depths was established and tested with measured values. The results showed that the experimental equation of infiltration had a high correlation coefficient between the measured value and the calculated value. There was a positive correlation between soil moisture uniformity and buried depth, and the suitable buried depths of clay loam of miostube-irrigation were between 15 and 20 cm.