The synergistic effects of climate change and fertilizer on crop yield: evidence from winter wheat in China

Climate variability and agricultural management practices, particularly fertilizer use, jointly determine crop production and food security. Understanding their synergistic effects is essential for developing climate-resilient farming strategies, yet the complex interactions between climate and fertilizer use in shaping crop yields remain poorly understood. Focusing on winter wheat in China, this study evaluates how climate change and fertilizer use jointly influence yield dynamics using a panel data model that integrates growing degree days (GDD[0,30]), extreme degree days (EDD[30+]), precipitation, and fertilizer interactions. From 1982 to 2020, winter wheat growing seasons warmed significantly (0.39 °C per decade, P < 0.01), with yields marked sensitivity to climatic shifts. A rise of 100 GDDs reduced yield by -1.7%, while 10 additional EDDs decreased yields by 0.2-1.6%. Precipitation shifts also played a role: a 50 mm increase correlated with yield changes ranging from -1.7% to +2.2%. In contrast, fertilizer application exerted a substantial positive effect, as each additional 10 kg ha-1 of fertilizer boosted yields by 1.6-2.2%. Spatially, climate impacts were heterogeneous: northern regions saw modest yield gains (+2.7%), while southern areas experienced declines of up to -4.4%. Fertilizer use, however, consistently offset losses, increasing yields by 12.8-49.8%. Synergistic climate-fertilizer interactions critically govern winter wheat yield responses to warming. Strategic fertilizer management can counter climate-related losses but requires location-specific optimization to avoid diminishing returns and environmental tradeoffs. These insights underscore the urgency of integrating the interaction dynamic into climate impact assessments and agricultural policy to ensure food security in a warming world. © 2025 Society of Chemical Industry.