大田滴灌系统灌水均匀度评价方法的探讨

Discussion on Method for Evaluation of Irrigation Uniformity under Field Drip Irrigation System

通过水力学计算和大田试验,分析了设计均匀度(Cu)与田间实测均匀度(Cuw、Du)的差异以及不同水肥耦合模式对土壤水分均匀度的影响。结果表明,在试验所用滴灌带的制造技术水平下,在平坡铺设时,根据现行的微灌技术规范设计的毛管极限长度存在着一定的加长空间;在冬小麦的返青期和拔节期,根系层的Cuw接近或者高于系统设计均匀度Cu,在进行配水均匀度Du与Cuw的相互换算时,建议适当考虑空间变异性对均匀度折算系数的影响;水肥耦合模式基本不影响土壤水分均匀度。

Irrigation uniformity was an important index to evaluate the effect of irrigation,so a hydraulic calculation and a two-year field experiment were conducted to access the differences of designed uniformity of system（Cu）and uniformity of soil water moisture（Cuw,Du）,and effects of water-fertilizer coupling on uniformity of soil water moisture.The results indicated that the limit length of tubes could be increased to some extent based on the prevailing technical standard of micro-irrigation project of China,if the system was laid at flat slope with the tubes used in the experiments.At the green returned stage and jointing stage of winter wheat,uniformity of soil water moisture（Cuw）was close to,or higher than designed uniformity of system（Cu）.When processing a conversion of soil water distribution uniformity（Du）and Christiansen coefficient（Cuw）,the effects of spatial variability on the reduction factor of uniformity should be considered appropriately.In addition,there was an obvious effect of water-fertilizer coupling on uniformity of soil water moisture actually.