Percolation is one of the important factors in the field water cycle, which affects designing irrigation schedules and increasing water productivity. However, the measurement of percolation is both costly and time‐consuming. This study established a point‐scaled system dynamic model (SDM) for water movement in the root zone of winter wheat in Shijin Irrigation District (SID) and proposed a semi‐distributed method to extend the SDM from the point to regional scales (SM). Observations of soil moisture of the root zone (0–2 m) of winter wheat from 2007 to 2009 were used to evaluate the SDM and SM. Both could accurately simulate soil water movement during the winter wheat growth period (R² > 0.6, RMSE < 0.032). Meanwhile, three extreme scenarios and sensitivity analysis were also applied to ensure the stability and plausibility of the SDM. The distribution of percolation indicated that irrigation was the main reason for percolation. Furthermore, well irrigation reduced the percolation when compared with canal irrigation. Meanwhile, wells were the main water source (56.3%) for the SID and percolation consumed about 22.1% income water. Future study should focus on improving simulation accuracy for spatial variability and consider the lateral exchange of soil water for regions with hills and mountains. © 2020 John Wiley & Sons, Ltd.

中文翻译：

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基于系统动力学和半分布式建模确定冬小麦渗流的空间分布*

渗滤是田间水循环的重要因素之一，它影响灌溉计划的设计和水生产率的提高。但是，渗滤的测量既昂贵又费时。本研究建立了石津灌区冬小麦根区水分运动的点尺度系统动态模型（SDM），并提出了一种半分布式方法将SDM从点扩展到区域尺度（SM）。 。利用2007年至2009年冬小麦根区（0–2 m）的土壤湿度观测值来评估SDM和SM。两者都可以准确模拟冬小麦生育期的土壤水分运动（R ²> 0.6，RMSE <0.032）。同时，还应用了三种极端情况和敏感性分析来确保SDM的稳定性和合理性。渗滤的分布表明灌溉是渗滤的主要原因。此外，与渠道灌溉相比，井灌减少了渗滤。同时，水井是SID的主要水源（56.3％），渗滤消耗了约22.1％的收入水。未来的研究应集中于提高空间变异性的模拟精度，并考虑丘陵和山区区域土壤水的横向交换。©2020 John Wiley＆Sons，Ltd.