土壤质地对地下滴灌灌水器水力要素的影响

Effect of Different Textural Soils on Hydraulic Characteristics of Emitters under Subsurface Drip Irrigation

为研究不同质地土壤中灌水器水力要素的变化规律及其差异，选取灌水器工作压力、土壤容重和土壤初始含水率为因素，分别在粘土、壤土和砂土中采用混合水平均匀设计安排试验。试验结果表明，不同土壤中的灌水器出流规律一致：即当工作压力不变时，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1～2min；在相同压力下，地下滴灌灌水器流量比地表滴灌小5％～20％，压力越大，二者越接近；灌水器流量随工作压力的增加而增大；土壤因素对灌水器流量有微弱的制约作用，使流量减小。相同条件下，土壤质地越轻，灌水器流量越大；但随着土壤容重和土壤初始含水率的增加，土壤质地越轻，流量减小程度越大。

In order to study hydraulic characteristics and their differences of SDI emitter in various textural soils and to analyze effect of soil factors on emitter discharge, the experimental scheme was arranged in the clay, loam and sand soil based on uniform design with mixed levels of three factors that were respectively work pressure of emitter, soil bulk density and soil initial water content. The results show that the rules of emitter discharges in three textural soils are the same. The discharge of SDI emitter is slightly big at the beginning of irrigation, but it is reduced and tends to be constant after 1 -2 min when work pressure remains invariable. At the same work pressure, the discharge of SDI emitter is smaller about 5--20 percent than that of DI emitter. The work pressure is higher, and the discharge of SDI emitter is bigger, and the discharge of both SDI and DI are closer. Soil factors slightly restrict emitter discharge. The lighter textured soil it is, the bigger emitter discharge will be. But discharge reduction of emitter in three textural soils with increase of soil bulk density or soil initial water content is bigger in sandy soil, smaller in loam soil and smallest in clay soil.