Evaluation of irrigation water saving and salinity control practices of maize and sunflower in the upper Yellow River basin with an agro-hydrological model based method.

Unreasonable irrigation water saving and salinity control practices (IWS-SCPs) have resulted in a shallow groundwater table, severe soil salinization and low water use efficiency in the upper Yellow River basin (YRB), Northwest China. In our study, a framework was developed by coupling the agro-hydrological model, i.e., AHC (Agro-Hydrological & chemical and Crop systems simulator) with a decision-making method, i.e., VIKOR (VlseKriterijuska Optimizacija I Komoromisno Resenje), and then a comprehensive evaluation index was calculated to assess the IWS-SCPs for maize and sunflower in the upper YRB. The AHC model was calibrated and validated with two years of field measured data, and then it was used to perform the simulations of agro-hydrological processes corresponding to the designed scenarios considering the irrigation depth and groundwater table depth (GWD) under the conditions of different hydrological years and degrees of soil salinization. The simulated crop yield, soil salinity variation, and crop water productivity were used as the evaluation indicators to search for appropriate IWS-SCPs of the target crops. The results showed that the recommended IWS-SCPs for maize were those with GWDs between 2.1 − 2.3 m and irrigation depths approximately 10% lower for non-saline soils in wet years and 10% higher than the present irrigation for slightly and moderately saline soils in normal and dry years. Whereas, the IWS-SCPs with GWD between 1.5 − 2.2 m and an irrigation depth of approximately 10 − 30% lower than the present situation could be recommended for sunflower in wet years and normal years regardless of saline soils and in dry years of non-saline soils. The developed framework and the obtained results are expected to provide a decision tool and implications for improving irrigation efficiency and salinity control in the arid upper YRB as well as other areas with similar climate conditions and shallow groundwater. • Coupling AHC model and VIKOR method provided a decision tool for water saving and salinity control. • The framework could be used as a decision tool for irrigation management and salinity control. • The appropriate groundwater depth for maize is 0.6 m deeper than that for sunflower. • Approximately 10%− 30% of irrigation water can be saved for sunflower in the upper Yellow River basin. [ABSTRACT FROM AUTHOR]