Blending controlled-release urea (CRU) with conventional urea has the potential to be an effective option for improving nitrogen (N) use efficiency (NUE), although determination of optimal blends in combination with a reduced N application rate has not been well studied. A field experiment was conducted to compare the effects of CRU (a mixture of polymer-coated urea and urea with N ratios of 100:00, 75:25, and 50:50 at 144 kg N ha⁻¹, hereafter denoted as CRU1, CRU2, and CRU3, respectively), urea at 180 (U1) and 144 kg N ha⁻¹ (U2) and a control (no N fertilizer applied, CK) on grain yield, NUE, and economic benefits in a wheat–maize rotation system. The CRU treatments were one-time applied, while for the U treatments, fertilizer N was applied in a split application. The results suggest that a one-time application of CRU prior to sowing of both crops fulfilled the demand of crop plants for N across the entire growth period. Relative to U1, the CRU treatments achieved approximately the same grain yield and 4.7–26.6% greater NUE at 20% reduced N application. Moreover, under CRU2, the yield, NUE, and economic benefits were increased by 12.2%, 9.7%, and 19.1%, respectively, for wheat, and under CRU3, they were increased by 10.9%, 20.6%, and 17.3%, respectively, for maize, compared with the U2 treatment. These results demonstrate that a mixture of CRU and urea at a ratio of 75:25 for wheat and 50:50 for maize with a 20% reduction in N application rate can maintain productivity, while enhancing NUE in the North China Plain.

将控释尿素（CRU）与常规尿素掺混有可能成为提高氮（N）使用效率（NUE）的有效选择，尽管尚未对充分掺混和降低氮肥施用量的最佳方法进行研究。进行了野外试验以比较CRU（144千克N ha ^-1下聚合物涂覆的尿素与N比为100：00、75 ：25和50:50的尿素的混合物，以下称为CRU1， CRU2和CRU3），尿素180（U1）和144 kg N ha ^-1（U2）和对照（不施氮肥，CK）对小麦-玉米轮作系统的谷物产量，NUE和经济效益的影响。一次性施用CRU处理，而对于U处理，则分次施用肥料N。结果表明，在两种作物播种前一次性施用CRU可以满足整个生育期作物对氮的需求。相对于U1，在减少施氮量20％的情况下，CRU处理可达到大致相同的谷物产量，并提高NUE 4.7-26.6％。此外，在CRU2下，小麦的产量，NUE和经济效益分别增加了12.2％，9.7％和19.1％，在CRU3下，小麦的产量，NUE和经济收益分别增加了10.9％，20.6％和17.3％。 ，对于玉米，与U2处理相比。