大田滴灌条件下土壤水分运移规律的试验研究

Experimental Research of Soil Water Transport under Drip Irrigation

研究了大田滴灌条件下,不同灌水量、不同滴头流量以及不同的土壤剖面容重条件下水分在土壤中的迁移规律。结果表明:在大田滴灌条件下,地表沿滴头土壤湿润锋基本呈圆形分布,在一定灌水量和滴灌流量条件下,土壤垂直湿润锋明显地大于水平湿润锋,且随着灌水量的增加呈线性关系;在同一灌水量下,随着滴头流量的增大,湿润体水平扩散半径(r)和竖直入渗深度(h)也相应变大;在不同灌水量下,湿润体水平和竖直湿润速度随着时间的增大都逐渐变小;随着剖面土壤容重的增加,水平湿润锋的迁移加快,水平湿润锋随时间的变化呈显著的幂函数关系;随着灌水量的增加,不同剖面容重下的土壤水平湿润锋速率的增加逐渐变小,而垂直湿润锋则呈变大的趋势。

The experiment was conducted to investigate the effect of different drip discharge, irrigation water quantity and two kinds of soil profile bulk density on transport of the soil water with drip irrigation.The results show that the wetting soil in the surface of soil profile present about circular distribution under drip irrigation. It is obvious that vertical wetting front distance is bigger than horizontal as the same drip discharge and quantity, and present linear increase with irrigation water quantity. The horizontal radius and the vertical depth increase with drip discharge increase under same irrigation water quantity. The wetting front speed of the horizontal and vertical were reduced gradually with irrigation time under same irrigation water quantity. The horizontal infiltration rates remarkable increase with the increase of soil profile bulk density, and could be express by power function. The increased speed of horizontal wetting front decreases gradually opposed to vertical wetting front with increased of irrigation water quantity in different soil bulk density.