Significant differences in agro-hydrological processes and water productivity between canal- and well-irrigated areas in an arid region

Abstract

Understanding the agro-hydrological processes and water productivity of canal- and well-irrigated systems is vital for agricultural water management in arid regions. In this study, the Agro-Hydrological & chemical and Crop systems simulator (AHC) was used in a distributed manner to evaluate the agro-hydrological processes and to assess water productivity under the conditions of canal- and well-irrigated systems. With the Heji irrigation system (Heji) located in the arid upper Yellow River basin, Northwest China as the case study area, the AHC was calibrated and validated by the field observation data of 2018 and 2019. Then the model was used in a distributed manner for the entire Heji. Results showed that there were significant differences in the agro-hydrological processes and water productivity between canal- and well-irrigated areas. The spatially averaged actual evapotranspiration was larger in canal-irrigated areas, and the cumulative net bottom water and salt fluxes were mainly downward in well-irrigated areas. The applied water was used more efficiently with higher equivalent water productivity of water applied (EWPIP) in canal-irrigated areas. However, the total water consumption (evapotranspiration) was in higher efficient utilization with higher equivalent water productivity of water consumption (EWPET) in well-irrigated areas. These findings can provide implications for regional irrigation water management and salinity control in the arid areas.