灌水量和入渗压力对大容量渗灌器入渗特性的影响

Effects of irrigation volume and infiltration pressure on infiltration characteristics of large capacity infiltration irrigation

【目的】掌握大容量渗灌器在不同入渗条件下的土壤水分运动及入渗规律.【方法】利用室内模拟土柱试验,研究了土壤湿润体的形状以及灌水量和入渗压力对渗灌器入渗特性的影响.【结果】距离对称剖面大于9.2cm的湿润体剖面近似为半椭球体;入渗初期在水头的作用下湿润峰的运移速率较快,之后湿润峰处于稳定增加的趋势,湿润峰的运移距离(y)与时间(t)的关系可以用乘幂关系表达y=mtn,拟合相关性达到显著水平.在水分再分布过程中湿润体垂直入渗距离的增加量逐渐大于水平方向的增加量,湿润比降低,在入渗后期重力式梯度占据主要的作用;土壤入渗率分析表明,0.4、0.7、1.0L的平均入渗速率分别为0.025、0.022、0.017L/s;一次灌水量越大的处理平均入渗速率越小.【结论】针对不同土壤的入渗能力和植物的根系生长范围,可通过调节入渗面的出口直径尺寸和灌水量的多少改变湿润比,具有较好的应用前景.

[Objective] To study the soil water movement and distribution under different infiltration conditions. [Method] Indoor column simulated experiments were conducted, the shape of the wetted soil body and the effects of the irrigation amount and the infiltration pressure were studied on the infiltration characteristics of the soil. [Result] Profile with a distance to symmetry plane more than 9.2 cm was ap- proximately a half ellipsoid. The migration rate of wetting front under the action of water head was faster at the initial stage,after that wetting front increased in a steady trend. Migration distance of wetting front （y） and time （t） were expressed by exponentiation relationship （y=mt＇）, the fitting correlation reached significant level. In the water redistribution process, the increase of the vertical infiltration distance was more than the increase of the horizontal direction,moist ratio decreased, gravity gradient occupied the main role. The analysis of soil infiltration rate showed that the average infiltration rates of 0. 4,0.7 and 1.0 L were 0. 025,0. 022 and 0. 017 L/s. The average infiltration rate decreases with the increase of irrigation a- mount. [Conclusion] The infiltration irrigation device has strong application prospects by aiming at the different soil water infiltration capacity and root growth range, moist ratio can be changed though adjusting outlet diameter size and irrigation amount.