The simulation of phosphorus (P) transport processes in rice irrigation areas plays a crucial role in managing eutrophication issues in downstream water bodies within the context of water conservation. Rice cultivation typically occurs in flat plains, where the soil and water environment of paddy fields undergo significant changes during the growth phase, particularly under water conservation practices. This study constructed a distributed model for the microenvironmental stratification of P transformation and transport in paddy fields, which was coupled with a hydrodynamic water quality model for river networks in irrigation areas. The model incorporated several crucial hydrological and water quality processes specific to rice irrigation areas, including water management within paddy fields, diffusion and coupled transformation processes of oxygen-iron-phosphorus in paddy soils, water partitioning-catchment processes in river networks, purification of P in rivers or drainage ditches, and other pertinent physical and biochemical processes related to P transport in irrigation areas. Application of the model in the Heping Irrigation District demonstrated that the simulation of water and P transport processes across various scales well matched the measured data. Both experimental and simulated results indicated that P loads in drainage ditches and rivers were primarily influenced by P discharge from upstream paddy fields, with the model effectively capturing the impact of hydrological fluctuations in paddy fields on P transformation and transport. Thus, the model proves highly suitable for assessing P loads in irrigation districts under varying water management practices.

中文翻译：

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水稻灌溉系统中的磷动力学建模：整合 O-Fe-P 耦合和区域水循环


在水资源保护的背景下，模拟水稻灌溉区磷 （P） 运输过程在管理下游水体的富营养化问题方面起着至关重要的作用。水稻种植通常发生在平坦的平原上，稻田的土壤和水环境在生长阶段发生了重大变化，尤其是在节水措施下。本研究构建了稻田 P 转化和运输微环境分层的分布式模型，并与灌区河网的水动力水质模型相结合。该模型结合了水稻灌溉区特有的几个关键水文和水质过程，包括稻田内的水资源管理、水稻土壤中氧-铁-磷的扩散和耦合转化过程、河流中的水分配-集水过程、河流或排水沟中磷的净化，以及与灌溉区磷运输相关的其他相关物理和生化过程。该模型在和平灌区的应用表明，各种尺度上水和磷的运输过程模拟与测量数据非常吻合。试验和模拟结果表明，排水沟和河流的磷负荷主要受上游稻田磷排放的影响，该模型有效地捕捉了稻田水文波动对磷转化和运输的影响。因此，该模型被证明非常适合评估不同水管理实践下灌区的 P 负荷。