VIC–CropSyst-v2: A regional-scale modeling platform to simulate the nexus of climate, hydrology, cropping systems, and human decisions

Food supply is affected by a complex nexus of land, atmosphere, and human processes, including short- and long-term stressors (e.g., drought and climate change, respectively). A simulation platform that captures these complex elements can be used to inform policy and best management practices to promote sustainable agriculture. We have developed a tightly-coupled framework using the macroscale Variable Infiltration Capacity (VIC) hydrologic model and the CropSyst agricultural model. A mechanistic irrigation module has been developed for inclusion in this framework. The performance of VIC-CropSyst was evaluated using two flux tower sites located in agricultural fields in the U.S. (Nebraska and Illinois). The agreement between recorded and simulated evapotranspiration (ET), applied irrigation water, soil moisture, leaf area index (LAI), and yield indicated that, although the model is intended to work at regional scales, it also captures field scale processes in agricultural areas. We also evaluated the regional simulations of VIC-CropSyst's ET over the Washington, Idaho and Oregon in the U.S. VIC-CropSyst is being used in conjunction with socio-economic models, river system models and atmospheric models to simulate the feedback processes between regional water availability, agricultural water management decisions and land-atmospheric interactions.