地下滴灌灌水器水力要素试验研究

Experimental study on hydraulic characteristics of emitter under subsurface drip irrigation

为了研究灌水器流量变化规律,该文以灌水器工作压力、土壤容重和土壤初始含水率为试验因素,用混合水平均匀设计安排试验方案。应用研制的地下滴灌灌水器流量测试系统,用称重法来获得不同试验方案灌水器流量。根据试验数据,建立了地下滴灌灌水器流量计算经验公式。分析表明:在工作压力不变时,灌水器流量在灌水初期略大,而后减小并趋于恒定,这个变化过程仅1～2 min左右,可认为灌水器流量是不变的;在同一压力下,地下滴灌灌水器流量比地表滴灌减小5%～20%,压力越大,二者值越接近;影响地下滴灌灌水器流量的主要因素是灌水器工作压力,而土壤容重和土壤初始含水率对灌水器流量影响较小。

In order to study the change laws of subsurface drip irrigation （SDI） emitter discharge, the experiment scheme was arranged based on uniform design with mix levels of three factors such as work pressure of emitter, soil bulk density and initial soil water content. The discharges of SDI emitter under various experimental schemes were obtained through weighing means by laboratory test system of SDI emitter discharge. The empirical formula for calculating SDI emitter discharge is established based on the test data. Analysis results show that discharge of SDI emitter is slightly biger at the beginning of irrigation, but then reduces and tends to be constant after 1-2 min when work pressure remains invariable. Therefore, SDI emitter discharge can be considered as a constant. Under the same work pressure, the discharge of SDI emitter is smaller of about 5%-20% than that of drip irrigation （DI） emitter. Work pressure is higher, the emitter discharges of both SDI and DI are closer. Work pressure is the decisive factor to hydraulic characteristics of SDI emitter. The influences of soil bulk density and initial soil water content on SDI emitter discharge are not remarkable.