田间膜下滴灌土壤水分运动特征试验研究

Experimental Study on Soil Water Movement Characteristics in Field Drip Irrigation under Film

通过田间试验,分析了滴灌条件下土壤水分运动过程,以及湿润体变化特征,结果表明地表积水半径达到稳定的时间和达到的稳定值随着滴头流量的增大而增大,地表积水半径稳定值与滴头流量符合乘幂关系。水平湿润半径随着入渗时间的增加而逐渐变大,在入渗的开始阶段湿润半径增加的速率较大,随着时间的延长速率逐渐变慢。滴头流量大,相同时刻的湿润体水平距离大,故水分运动快,反之水分运移越慢。湿润半径差值随时间的延长而不断增加。通过分析滴灌水平湿润锋和入渗时间之间关系可知,水平湿润锋和入渗时间之间存在着显著的幂函数关系,其中的拟合系数与滴头流量有关。

In the paper, soil water movement process and wetting body variation characteristics under drip irrigation were analyzed according to field experiment. The results are as follows： the time and the value of reaching steady of surface pools radius increase as the dripper flow rate increases, power function fits well to the steady value of surface pools radius and the dripper flow rate. The longer the infiltration time, the bigger the horizon wetting radius, the increasing rate of wetting radius is faster at the beginning of infiltra- tion and it becomes slow gradually as time increases. The larger the dripper flow rate, the farther the level distance of wetting body at the same time, so the water movement is fast, on the other hand, it＇s slow. The difference of wetting radius is increasing constantly as time increases. Through analyzing the relation- ship between the infiltration time and the horizontal wetting front, we can learn that power function fits well to the infiltration time and the horizontal wetting front, and the fitting coefficient are related to the dripper flow rate.