Precision Controlled‐Release Urea Blending by Maize Variety: Optimising Nitrogen Release to Reduce Ammonia Emissions and Boost Sustainability

ABSTRACT Agricultural ammonia (NH 3 ) emissions impair nitrogen use efficiency and exacerbate environmental pollution. While most research has focused on suppressing NH 3 volatilisation through nitrogen source modification, the synergistic role of matching fertiliser types with crop genetic traits remains largely overlooked. Here, we examined the potential of combining controlled‐release urea (CRU) with maize varietal selection to mitigate NH 3 emissions in summer maize on the North China Plain, integrating data synthesis with a two‐year field experiment (2021–2022). Results indicated an average NH 3 volatilisation rate of 10.35%, strongly governed by nitrogen rate, fertiliser type and maize variety. Field trials evaluated four nitrogen treatments at 180 kg N ha −1 —N180U (100% conventional urea), N180C1 (one‐third CRU + two‐thirds conventional urea), N180C2 (two‐thirds CRU + one‐third conventional urea) and N180C (100% CRU)—applied to an early‐maturing (JNK728) and a late‐maturing (ZD958) variety. The results show that compared with other treatments, N180C1 and N180C2 increased the grain yield of JNK728 by 10%–17.4% and ZD958 by 5.5%–24.5% over two growing seasons. Relative to conventional urea (N180U), N180C1 reduced NH 3 emissions by 23.52%–23.56% and enhanced agricultural sustainability by 154.11% for JNK728, whereas N180C2 achieved reductions of 23.62%–27.83% in NH 3 emissions and a 162.63% improvement in sustainability for ZD958. The structural equation model reveals the underlying mechanism: This fertilisation strategy tailored for different crop varieties not only reduces the peak concentration of ammonium nitrogen in the soil but also promotes root growth, enhances nitrogen absorption efficiency and ultimately reduces ammonia volatilisation losses. Our findings establish that coupling CRU with variety‐specific management forms a potent two‐dimensional plant–nitrogen strategy, effectively curtailing NH 3 emissions while advancing the productivity and sustainability of maize systems.