Assessing the impact of various irrigation technologies on agricultural production: A water-energy‑carbon nexus perspective

Effective coordination of water, energy, and carbon is vital for the sustainable development of irrigated agriculture. However, limited research has been conducted on the impact of irrigation technology on the coupling and coordination relationship of these elements, especially on the North China Plain (NCP) where irrigation is applied extensively. This study establishes a water-energy‑carbon (WEC) nexus framework based on footprint theory and energy analysis. Water utilization, energy consumption, and carbon emissions in a wheat production system under conventional irrigation (CI), sprinkler irrigation (SI), and drip irrigation (DI) technology on the NCP from 2000 to 2019 were quantified. Subsequently, the coupling coordination degree (CCD) model is used to analyze the interactions and correlations of the WEC nexus. Results indicated that SI and CI effectively reduced water consumption and mitigated water degradation, but this came at the expense of increased energy consumption and carbon emissions. The irrigation process represented the predominant share of energy consumption, representing 40.54 % and 37.64 % of the production-based energy consumption under SI and DI, respectively. The primary contributors to the production-based carbon footprint under CI, SI, and DI were N fertilizer (23.67 %), pipeline production (59.10 %), and irrigation electricity (21.85 %), respectively. The CCD range of WEC systems under the three irrigation technologies varied from 0.35 to 0.50 on the NCP during the investigation period. There were some slight differences in the average annual CCD between each irrigation technology, with DI (0.43) > SI (0.40) > CI (0.39). SI and DI was in basic coordination, while CI was in imbalanced type. Meanwhile, the spatial heterogeneity of CCD was fully reflected over time. Promoting water-saving irrigation technologies, developing clean energy, controlling the expansion of irrigation areas, and strengthening the connections among various subsystems are crucial measure to achieve regional WEC nexus coupling coordination.