Assessment of irrigation and groundwater management strategies in cold arid areas with shallow groundwater tables using a coupled year-round agro-hydrological model

Quantitatively assessing the impact of irrigation and groundwater management strategies is crucial for improving water productivity and soil salinity control in cold arid areas with shallow groundwater tables (CAASGT). However, existing studies often focus on specific periods, either the crop growth period or the freeze-thaw period, due to the lack of appropriate models that can accurately represent both soil freeze-thaw and crop growth processes. This limited focus results in incomplete year-round insights, given the significant differences and interactions in hydrological processes during these two periods. In this study, we coupled the agro-hydrological model (i.e., the AHC model) and the cold region hydrological model (i.e., the SHAW model) to simulate the year-round agro-hydrological processes and crop growth in CAASGT. The coupled model was rigorously calibrated and validated using two years of field experiment data collected from a maize field in the upper Yellow River basin (YRB). Subsequently, the validated model was employed to analyze the effect of different irrigation and groundwater management scenarios on crop yield, soil salinity, and water productivity in two hydrological years (dry and wet years). Results indicated that increasing groundwater depth was beneficial for soil salinity control in all scenarios but reduced maize yield at low irrigation levels. Autumn irrigation proves essential for soil salinity control, with reducing the irrigation amount in autumn irrigation period having a more significant impact on maize yield than that in growing season. Additionally, soil thawing time significantly affects soil salt accumulation and crop yield, with earlier thawing time leading to more severe salt accumulation at the end of the freeze-thaw period, restraining maize seedling growth and decreasing maize yield. These results are expected to offer year-round insights into improving water productivity and soil salinity control in CAASGT.