Different irrigation treatments in plants significantly influence CO₂ emissions. This study investigated the net ecosystem CO₂ exchange (NEE) and yield of maize cropland under different irrigation treatments to determine the optimal irrigation treatment at different maize growth stages. Different degrees of water deficit irrigation were carried out in four fields: full irrigation, 100% evapotranspiration (ET); moderate deficit irrigation, 65% ET; and severe deficit irrigation, 40% ET. Automated static and dynamic chambers were used to measure CO₂ fluxes. We found that NEE showed a “V” -shaped trend during the day and slowly declined at night. The light response parameters were calculated using the rectangular hyperbola model, and the leaf area index accounted for 85% of the light use efficiency. In the late vegetative stage, severe deficit irrigation led to a reduction in CO₂ emissions but significantly reduced the crop growth rate (p < 0.05). In the reproductive stage, full irrigation not only reduced CO₂ emissions but also significantly increased the crop growth rate. In the maturation stage, moderate deficit irrigation reduced CO₂ emissions, and the crop growth rate decreased compared with full irrigation, but the decrease was not significant (p > 0.05). Compared with full irrigation throughout the growth period, full irrigation in the reproductive stage and moderate deficit irrigation in the late vegetative and reproductive stages both increased the maize carbon sink capacity and light use efficiency at higher leaf area index, and the harvest index did not decrease significantly. However, inadequate irrigation in the reproductive stage or severe deficit irrigation in the late vegetative and maturation stages significantly reduced the maize harvest index. Thus, full irrigation during the reproductive stage, and moderate deficit irrigation during the late vegetative and reproductive stages were the optimal irrigation strategies for saving water, reducing CO₂ emissions and ensuring a satisfactory maize yield.

植物中不同的灌溉处理显着影响CO ₂排放。本研究调查了不同灌溉处理下玉米农田的净生态系统CO ₂交换（NEE）和产量，以确定玉米不同生长阶段的最佳灌溉处理。4个田地进行不同程度的缺水灌溉：全灌、100%蒸散量（ET）；中度亏缺灌溉，65% ET；和严重亏缺灌溉，40% ET。自动静态和动态室用于测量 CO ₂通量。我们发现NEE在白天呈“V”形趋势，夜间缓慢下降。采用矩形双曲线模型计算光响应参数，叶面积指数占光利用效率的85%。在植物生长后期，严重的亏缺灌溉导致CO ₂排放量减少，但显着降低了作物生长速度（p < 0.05）。在生殖阶段，充分灌溉不仅减少了CO ₂排放，而且显着提高了作物生长速度。在成熟阶段，适度亏缺灌溉减少了 CO ₂与全灌相比，作物生长速度有所下降，但下降不显着（p > 0.05）。与整个生育期全灌相比，生殖期全灌和营养后期和生殖后期适度亏缺灌溉在较高叶面积指数下均提高了玉米的碳汇能力和光能利用效率，而收获指数并未降低显着地。然而，生殖期灌溉不足或营养后期和成熟后期灌溉严重不足，显着降低了玉米收获指数。因此，生殖期全灌和营养后期和生殖期适度亏缺灌溉是节水、减少二氧化碳的最佳灌溉策略。₂排放量并确保玉米产量令人满意。