Nitrous oxide emissions and driving factors in peach (Prunus persica L.) orchards with different nitrogen inputs

Fruit production has been growing to meet global nutritional demands, but it has also become a significant source of greenhouse gas emissions, especially nitrous oxide (N₂O), in agriculture. Agronomic management in orchards differs from that in farmlands, resulting in distinct patterns of N₂O emissions. However, N₂O emissions and the factors that drive them in orchards are still little understood. In this study, we conducted a field experiment to assess N₂O emissions in two peach orchards in North China with varying nitrogen (N) inputs and summarized peer-reviewed data from 42 N₂O measurements across seven peach orchard studies through literature synthesis. We found that N application significantly raised N₂O emissions in the two peach orchards. The cumulative N₂O emission in the conventional N treatment was averagely 8.8 kg N ha^-1 yr^-1 (emission factor of 1.4 %) in both orchards, which was 8.2 times greater than in the no-N treatment. Soil nitrate content, precipitation, soil water-filled pore space (WFPS), and soil temperature were significant factors driving N₂O emissions. Literature synthesis revealed that the average N₂O emission in other orchards with N application was 5.6 kg ha^-1 yr^-1 (emission factor of 1.7 %), and N₂O emissions raised linearly with N fertilizer rates (y = 0.6992 + 0.0177x, R² = 0.85, P < 0.001). This study highlights the importance of fertilized peach orchards as N₂O sources, with N inputs and climate conditions being the primary drivers. These findings contribute to refining global greenhouse gas inventories and propose emission reduction measures.