Water distribution uniformity is important for assessing the hydraulic performance of sprinkler nozzles and designing sprinkler irrigation systems. However, current studies rarely consider the redistribution abilities of sprinkler water in the soil and judge whether a sprinkler system is qualified based only on the coefficient of uniformity on the ground (CUg), which leads to a serious underestimation of the actual irrigation effect of sprinkler irrigation projects. Hence, this study establishes and validates a COMSOL-3D model to simulate the movement of soil water during sprinkler irrigation. Moreover, the effects of the soil hydraulic and irrigation parameters on the coefficient of soil moisture content uniformity (CUs) were explored. The results showed that 1) the Nash-Sutcliffe efficiency coefficient (NSE) of the vertical wetting front (VWF) and soil moisture content (SMC) in the two sets of validation experiments was 0.965 and 0.862 and 0.867 and 0.900, respectively. 2) Owing to the differences in soil saturated hydraulic conductivity, after the end of irrigation, the VWF transport rates in vertical direction differed among the three textured soils, with loam exhibiting the highest rate, followed clay loam and silty clay. However, their CUs increased with increasing water transport time, indicating that the water distribution within the sprinkler-wetted zone became increasingly homogeneous as the sprinkler irrigation water was transported and diffused from the top to bottom in the soil. 3) Dimensional analyses showed that CUs were strongly influenced by the initial soil moisture content, irrigation time, and water transport time. 4) In Case 4, when CUg was reduced from 81.9 % to 60 %, CUs only decreased from 83.2 % to 81.4 % after 48 h of irrigation, indicating that the sprinkler irrigation water had good redistributive ability. This study provides a reference for rationally reducing the CUs of sprinkler irrigation projects and maximising project investments and planting interest.

中文翻译：

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使用 COMSOL-3D 模型模拟喷灌系统土壤含水量均匀性的系数


配水均匀性对于评估喷灌喷嘴的水力性能和设计喷灌系统非常重要。然而，目前的研究很少考虑喷灌水在土壤中的再分配能力，仅根据地面均匀系数 （CUg） 来判断喷灌系统是否合格，导致严重低估了喷灌工程的实际灌溉效果。因此，本研究建立并验证了一个 COMSOL-3D 模型，用于模拟喷灌过程中土壤水的运动。此外，还探讨了土壤水力和灌溉参数对土壤含水量均匀系数 （CUs） 的影响。结果表明：1）两组验证试验中垂直湿润前沿（VWF）和土壤含水量（SMC）的Nash-Sutcliffe效率系数（NSE）分别为0.965和0.862以及0.867和0.900。2） 由于土壤饱和导水率的差异，灌溉结束后，3 种纹理土的垂直向 VWF 输运速率不同，壤土最高，其次是粘壤土和粉质粘土。然而，它们的 CU 随着输水时间的增加而增加，这表明随着喷灌水在土壤中从上到下输送和扩散，喷灌湿区内的水分布变得越来越均匀。3） 维度分析表明，CUs 受初始土壤含水量、灌溉时间和水分输送时间的强烈影响。4） 在案例 4 中，当 CUg 从 81.9 % 降低到 60 % 时，CUs 仅从 83.2 % 下降到 81。灌溉 48 h 后 4 %，表明喷灌水具有良好的再分配能力。本研究为合理降低喷灌工程的 CUs，最大化工程投资和种植兴趣提供了参考。