间接地下滴灌土壤水分运移试验

Effect indirect subsurface drip irrigation on water migration

采用塔里木灌区沙壤土,利用室内土柱法对间接地下滴灌在不同透水边界高度、不透水边界高度、滴头流量及土壤初始含水率条件下土壤水分运移规律进行了研究.结果表明:在不同透水边界高度下灌水,透水边界相当于线源入渗,对横向最大湿润距离的影响较小,其湿润体形状呈椭球体;不透水边界高度对垂向最大湿润距离影响较大,并对表层土壤含水率的影响明显,不透水边界高度越小,水分越易于运移至土壤表层;随着滴头流量的增大,土壤湿润体在水平和垂直方向上最大湿润距离均呈减小趋势;随着初始含水率的增大,湿润锋在水平和垂直方向上的运移速度较明显地增加.

The indoor soil-column experiment was designed to analysis the law of water migration under different thickness of permeable boundary,thickness of impervious boundary,dripper discharge and initial soil moisture content in indirect subsurface drip irrigation with sandy loam from Tarim irrigation.The results showed that thickness of permeable boundary was equal to line source infiltration,impacted less on the maximum vertical infiltration distance,and the wetting body was ellipsoid.The thickness of impervious boundary had a higher impact on vertical infiltration distance,which also significantly impacted on surface soil moisture content;the smaller thickness of impervious boundary,the greater the surface soil moisture content.With the increase of dripper discharge,the wetting body decreased on vertical and horizontal the maximum infiltration distance,with the increase of initial soil moisture content,wetting front transport significantly increased in horizontal and vertical directions.