Irrigation is a common practice used to promote vegetable yields through high agricultural inputs, which potentially increases nitrous oxide (N₂O) emissions. However, it is still unclear how an effective irrigation strategy could increase yield by regulating soil water conditions, ultimately mitigating N₂O emissions. In this study, negative pressure irrigation (NPI) and furrow irrigation (FI) were applied to control two different soil conditions (i.e., the stable soil water content and the dry-wet cycles) in a vegetable greenhouse growing amaranth (Amaranthus hybridus L.) and lettuce (Lactuca sativa L.). The key objective was to assess the effect of irrigation on vegetable yields and N₂O emissions and further reveal their controlling factors. Compared to FI, NPI increased the seasonal stability of soil moisture, NH₄⁺-N, and NO₃⁻-N by 11.4%, 26.4%, and 21.2%, respectively. NPI also increased vegetable yields by 16.6%−20.3%, whereas the average area-scaled and yield-scaled N₂O emissions under NPI were 15.1% and 29.2% lower than FI, respectively. Notably, the N₂O emissions could be affected by soil moisture, temperature, NH₄⁺-N, NO₃⁻-N, and soil microbial biomass carbon and nitrogen, but the relative importance of these factors was different under the two irrigation systems due to different soil water conditions. The random forest (RF) model showed that soil moisture was the most crucial factor driving N₂O flux under FI, whereas soil NO₃⁻-N and NH₄⁺-N were the key governing factors under NPI. Overall, this study highlights the importance of increasing seasonal soil water stability for improving the sustainability of irrigation and NPI was a promising irrigation strategy to promote vegetable yields while mitigating N₂O emissions.

灌溉是一种常见的做法，用于通过高农业投入来提高蔬菜产量，这可能会增加一氧化二氮 (N ₂ O) 的排放。然而，目前尚不清楚有效的灌溉策略如何通过调节土壤水分条件来提高产量，最终减少 N ₂ O 排放。在这项研究中，负压灌溉（NPI）和沟灌（FI）被用于控制蔬菜温室种植苋菜（Amaranthus hybridus L. ) 和生菜 ( Lactuca sativa L.)。主要目标是评估灌溉对蔬菜产量和 N _2的影响O排放并进一步揭示其控制因素。与FI相比，NPI使土壤水分、NH ₄ ⁺ -N和NO ₃ ⁻ -N的季节稳定性分别提高了11.4%、26.4%和21.2%。NPI 还使蔬菜产量提高了 16.6%−20.3%，而NPI 下的平均面积尺度和产量尺度 N _{2 O 排放量分别比 FI 低 15.1% 和 29.2%。}值得注意的是，N ₂ O 排放量可能受到土壤水分、温度、NH ₄ ⁺ -N、NO ₃ ^{−的影响。}-N，以及土壤微生物生物量碳和氮，但由于土壤水分条件不同，这些因素在两种灌溉制度下的相对重要性不同。随机森林 (RF) 模型表明，在 FI 下，土壤水分是驱动 N ₂ O 通量的最关键因素，而土壤 NO ₃ ⁻ -N 和 NH ₄ ⁺ -N 是 NPI 下的关键控制因素。总的来说，这项研究强调了增加季节性土壤水分稳定性对于提高灌溉可持续性的重要性，而 NPI 是一种很有前途的灌溉策略，可以提高蔬菜产量，同时减少 N 2 _O排放。