土壤入渗特性和田面糙率的变异性对沟灌性能的影响

以杨凌区粘壤土和砂壤土区域进行的大田沟灌试验为基础,在假定各灌水沟内部土壤入渗特性和糙率均一的条件下,重点分析各灌水沟之间土壤入渗参数和田面糙率的不同组合对沟灌水流运动过程和灌水质量的影响,结果表明土壤入渗特性的变异性对沟灌水流推进过程和灌水质量指标影响较大,在模拟时必须充分考虑;而田面糙率的变异性对沟灌水流推进过程和灌水质量指标影响较小,可采用田块糙率均值代替各灌水沟的糙率。经实例验证,水流推进过程相对误差为7.28%,灌水效率、灌水均匀度和储水效率模拟值与实测值误差分别为5.74%、6.18%和4.07%,结果表明其模拟效果较好。

Effects of Spatial Variability of Soil Infiltration Characteristics and Manning Roughness on Furrow Irrigation Performance

Based on the furrow irrigation which was conducted in Yangling District with the clay loam and sandy loam, effects of different combinations of soil infiltration characteristics and Manning roughness on the water advance trajectory and irrigation performance were analyzed. The results show that the spatial variability of soil infiltration characteristics has a great effect on the water advance trajectory and irrigation performance. When optimizing the design of the furrow irrigation, the spatial variability of soil infiltration characteristics must be taken into consideration. However, the spatial variability of Manning roughness affects slightly on the water advance trajectory and irrigation performance. When optimizing the design of the furrow irrigation, the average value of Manning roughness can be used in various irrigation ditches. Based on the above results and verified field experiments, the results show that the average relative error between the measured and simulated values of the water advance trajectory is 7.28%, and the application efficiency, distribution uniformity and storage efficiency between the measured and simulated values are 5.74%, 6.18% and 4.07%, respectively.