Improving nitrogen use efficiency-yield (NUE_Yield) and crop water productivity (CWP) simultaneously has been a focus for sustainable wheat production, especially for the North China Plain, which faces challenges with limited water resources and low fertilizer use efficiency. With three-year wheat field experiments with two irrigation levels (rainfed, and irrigated at jointing and anthesis) and three N rates (0, 180, and 270 kg ha⁻¹), we systematically investigated the effect of irrigation and nitrogen management on wheat water consumption at different growth stages, and further determined on the relationship between CWP and NUE_Yield simultaneously under different irrigation and nitrogen interactions. The results showed that N application and irrigation increased the total crop water consumption (1.2%−3.6% and 42.4%−44.4%, respectively). Increasing the N rate improved the soil water use (7.5%−10.3%) and reduced crop dependence on irrigation and precipitation, whereas irrigation reduced soil water utilization (54.4%−57.8%). Both irrigation and N application significantly increased the amount, percentage, and intensity of water consumption, especially during the grain filling period. There was a significant positive synergistic relationship between CWP and NUE_Yield under different irrigation and nitrogen treatments. For every 1 kg m⁻³ increase in CWP, NUE_Yield increased by 2.71–11.37 kg kg⁻¹, depending on the N rate and water conditions. Increasing the N rate reduced the positive response of NUE_Yield to increasing CWP, while irrigation increased the positive response of NUE_Yield to increasing CWP. After decomposing NUE_Yield into nitrogen uptake efficiency (NuptE) and nitrogen utilization efficiency for yield (NutE_Yield), we found that the positive synergistic relationship between CWP and NUE_Yield was mainly due to the positive response of NuptE but not NutE_Yield to CWP. Irrigation increased the grain nitrogen accumulation efficiency by simultaneously increasing both pre-anthesis N translocation (GNA_T) and post-anthesis N assimilation (GNA_A) but increased GNA_T more significantly than GNA_A. Our results provide a theoretical basis for the efficient management of water and fertilizer in wheat production on the North China Plain and offer critical insights for improving the modeling of water-nitrogen relationships in wheat.

同时提高氮利用效率（NUE _Yield ）和作物水分生产力（CWP）一直是小麦可持续生产的重点，尤其是对于面临水资源有限和肥料利用效率低的挑战的华北平原而言。通过为期三年的麦田试验，采用两种灌溉水平（雨养，以及在拔节和开花时灌溉）和三种施氮量（0、180 和 270 kg ha ^-1），我们系统地研究了灌溉和氮管理对小麦的影响不同生长阶段的耗水量，进一步确定了 CWP 与 NUE_{产量的关系}同时在不同的灌溉和氮相互作用下。结果表明，施氮和灌溉增加了作物总耗水量（分别为1.2%-3.6%和42.4%-44.4%）。增加施氮量改善了土壤水分利用（7.5%-10.3%）并减少了作物对灌溉和降水的依赖，而灌溉降低了土壤水分利用（54.4%-57.8%）。灌溉和施氮均显着增加了耗水量、耗水百分比和耗水强度，尤其是在灌浆期。在不同的灌溉和施氮处理下，CWP 和 NUE_产量之间存在显着的正协同关系。CWP每增加 1 kg m ^-3，NUE_产量增加 2.71–11.37 kg kg^-1，取决于 N 速率和水条件。增加施氮量降低了 NUE_产量对增加 CWP 的正响应，而灌溉增加了 NUE_产量对增加 CWP 的正响应。将NUE _Yield分解为氮吸收效率(NuptE)和氮利用效率(NutE _Yield )后，我们发现CWP和NUE _Yield之间的正协同关系主要是由于NuptE的正响应而不是NutE _Yield对CWP的正响应。灌溉通过同时增加花前 N 易位（GNA _T) 和开花后 N 同化 (GNA _A ) 但增加 GNA _T比 GNA _A更显着。我们的研究结果为华北平原小麦生产中水肥的有效管理提供了理论基础，并为改进小麦水氮关系的建模提供了重要的见解。