Balancing N₂O and NH₃ emissions with maize yield: Investigating the role of alternate drip irrigation and 3,4-dimethylpyrazole phosphate (DMPP)

In the context of increasing climate variability and frequent wet-dry cycles, it is imperative to optimize nitrogen management to balance gaseous N losses with crop productivity. A two-year field experiment was conducted in the North China Plain to investigate irrigation pattern and fertilizer type (urea combined with 3,4-dimethylpyrazole phosphate, DMPP, and urea without DMPP) on soil N₂O and NH₃ emissions, soil temperature, water-filled pore space (WFPS), and maize yield. Four treatments were carried out: (1) alternate drip irrigation with DMPP (T1), (2) alternate drip irrigation without DMPP (T2), (3) conventional drip irrigation with DMPP (T3), and (4) conventional drip irrigation without DMPP (T4). Soil temperature and WFPS were identified as key drivers regulating both N₂O and NH₃ emissions, with emission pulses occurring shortly after irrigation and fertilization events, highlighting the dominant role of soil physical conditions in controlling nitrogen transformation processes. Compared with conventional drip irrigation, alternate drip irrigation reduced cumulative N₂O emissions by 0.9–10.5% ( P < 0.05), and this mitigation effect was further enhanced by DMPP, which decreased cumulative N₂O emissions by 22.2–50.3%. In contrast, the response of NH₃ emissions to irrigation patterns and fertilizer types was weaker and more variable, with DMPP increasing cumulative NH₃ emissions by up to 32.2% under conventional irrigation while decreasing them by up to 19.4% under alternate irrigation, though these effects exhibited significant interannual variation. Notably, the combined application of alternate drip irrigation and DMPP (T1) achieved the lowest cumulative N₂O and NH 3 emissions with 51.5–73.3% and 88.0–96.0%, respectively, while simultaneously increasing maize yield by 14.8–21.4%. These results suggest that integrating alternate drip irrigation with DMPP represents an effective strategy for mitigating nitrogen emissions and enhancing maize productivity in sandy loam soils typical of the North China Plain, while highlighting the need to consider trade-offs among different nitrogen loss pathways for sustainable agricultural management. • Alternate drip irrigation reduced cumulative N₂O emissions by 0.9–10.5%. • DMPP suppressed N₂O but had contrasting effects on NH₃ under different irrigation patterns. • NH₃ was driven by soil temperature and WFPS, while N₂O was mainly controlled by WFPS. • Alternate drip irrigation with DMPP minimized N₂O and NH₃ emissions and increased maize yield.