Waterlogging on croplands has been a known problem for a long time, leading to adverse social, physical, economic and environmental issues. To better solve the problem, the complicated plant-soil-water dynamics system needs to be better understood. The challenge is to simulate the interactions between the components in the systems. There are models that simulate plant-soil-water system but either run the processes independently leading to inaccuracy or has high invasiveness of using integrated models. This paper presents a tightly coupled model, DayCent-MODFLOW, that links a 3D ground-water flow (MODFLOW) model and a 1D agroecosystem model (DayCent). DayCent is responsible for plant-soil-water dynamic in the root zone, whereas MODFLOW simulates head and groundwater flow in the saturated zone of the aquifer. DayCent passes deep percolation from the soil profile to the water table and, under conditions of waterlogging in which the water table is within the soil profile, DayCent soil hydrologic processes are constrained by the presence of the water table simulated by MODFLOW. The coupling is achieved by adopting a parallel inter-process communication technique MPI (Message Passing Interface). The model is applied to a waterlogged agricultural area (22 km²) in northern Colorado, USA and tested against groundwater head and rates of evapotranspiration (ET). The model runs in parallel with multiple processes on the largest AWS Linux server. Groundwater heads match measured heads to a reasonable degree, and ET rates match reference ET and are highly correlated with crop type. Results show the strong hydrologic interaction between the two models. Greenhouse gas emissions from soil (N₂O and CH₄) were also estimated by the model under the waterlogged conditions. Although the model can be used to simulate any plant-soil-aquifer system, no matter the depth of the water table, results from this study show that the model can be used to assess crop productivity, recharge, ET, and greenhouse gas emissions in areas of shallow groundwater.

长期以来，农田内涝一直是一个众所周知的问题，会导致不利的社会、自然、经济和环境问题。为了更好地解决这个问题，需要更好地理解复杂的植物-土壤-水动力学系统。挑战在于模拟系统中组件之间的交互。有些模型可以模拟植物 - 土壤 - 水系统，但要么独立运行这些过程导致不准确，要么使用集成模型具有很高的侵入性。本文提出了一个紧密耦合的模型 DayCent-MODFLOW，它将 3D 地下水流 (MODFLOW) 模型和 1D 农业生态系统模型 (DayCent) 联系起来。DayCent 负责根区的植物-土壤-水动态，而 MODFLOW 模拟含水层饱和区的水头和地下水流。DayCent 将深层渗透从土壤剖面传递到地下水位，并且在地下水位在土壤剖面内的涝渍条件下，DayCent 土壤水文过程受到 MODFLOW 模拟的地下水位存在的限制。这种耦合是通过采用并行进程间通信技术MPI（Message Passing Interface）来实现的。该模型应用于一个涝渍农业区（22 km² ) 在美国科罗拉多州北部，并针对地下水头和蒸散率 (ET) 进行了测试。该模型与最大的 AWS Linux 服务器上的多个进程并行运行。地下水水头与测量水头在合理程度上匹配，ET 率与参考 ET 相匹配，并且与作物类型高度相关。结果表明两个模型之间存在很强的水文相互作用。土壤中的温室气体排放（N ₂ O 和 CH ₄) 也由模型在浸水条件下估计。尽管该模型可用于模拟任何植物-土壤-含水层系统，无论地下水位深度如何，本研究的结果表明该模型可用于评估作物生产力、补给、ET 和温室气体排放。浅层地下水区。