Global metaanalysis of the nonlinear response of soil nitrous oxide (N 2 O) emissions to fertilizer nitrogen

Significance We clarify the response of the greenhouse gas nitrous oxide (N 2 O) to nitrogen (N) fertilizer additions, a topic of considerable debate. Previous analyses have used single N-rate experiments to define a linear response to N additions across climate, management, and soil conditions globally. Here, we provide a first quantitative comparison of N 2 O emissions for all available studies that have used multiple N rates. Results show that a nonlinear emission factor better represents global emission patterns with lower uncertainty, offering more power for balancing the global N 2 O budget and for designing effective mitigation strategies.