Optimized integrated soil-crop system management enhances crop yield while reducing water resource consumption

Freshwater resources depletion and unreasonable nitrogen fertilizers application has been China’s major constraint for both the sustainability of agricultural production and socioeconomic development. Based on the long-term integrated soil-crop system management (ISSM, since 2009), this study optimized irrigation method to investigate water utilization and nitrogen utilization of optimizing ISSM and explore whether it can increase maize production while reducing water resource consumption. To accomplish these objectives, six treatments (CK, traditional cultivation practices; OPT1, redesign of cropping systems and nutrient treatments; O-OPT1, based on OPT1, optimizing irrigation method; HY, treatment to explore local yield potential; OPT2, optimized combination of cropping systems and nutrient treatments; and O-OPT2, based on OPT2, optimizing irrigation method) were conducted in 2022–2023. Results showed that the HY demonstrated the highest yield under the border irrigation method and increasing maize production by 49.8–50.7 %, compared to CK. However, the O-OPT2 with its optimized irrigation method and nutrient treatments used less water and fertilizer, with no significant difference in yield between O-OPT2 and HY, and increased the proportion of water allocation in late growth period compared to HY. The water footprint (WF) of O-OPT2 was decreased by 35.5–36.5 % and 36.9–37.8 % compared to CK and HY, respectively. Moreover, O-OPT2 mitigated soil evaporation by 7.8–10.8 % and reduced crop evapotranspiration (ETc) by 13.1–13.3 %, ultimately, both water use efficiency (WUE) and nitrogen use efficiency were significantly improved by 11.5–13.4 % and 132.5–136.4 %, respectively, compared to HY. In conclusion, the optimized ISSM can produce more grains at a lower water resource consumption.