• • Annual CF per unit yield ranges from 65.5 to 293.8 g CO2-eq/kg across 10 vegetables; open-field radish lowest, open-field green bean highest, indicating crop type and yield drive emission intensity.
• • Fertilizer production and field N2O emissions are dominant sources, contributing 40–80% (up to 80.4%) of CF; targeted nitrogen management can yield substantial reductions.
• • In facility systems, irrigation electricity and agricultural film inputs contribute up to 57.87% of CF, versus <2.5% for film in open-field; optimizing energy and material use is critical for facility horticulture.
• • Spatial heterogeneity is significant: facility eggplant and open-field green bean show largest inter-provincial variability; regional climate and energy mix necessitate tailored mitigation policies.