Abstract
Chinese orchards have emerged as emission hotspots of nitrous oxide (N2O) due to their high nitrogen (N) inputs. However, unique fertilizer application methods may lead to inaccuracies in monitoring and calculating N2O emissions, potentially resulting in overestimations or underestimations. The emission variation among different orchards and the dominant influencing factors also need further clarification. This study summarizes the methods used to monitor and estimate soil N2O emissions from orchards in China. It underscores the critical importance of appropriately arranging sampling boxes by considering fertilized and unfertilized areas and the range of irrigation radiation. Accurately scaling up chamber measurements to the landscape level requires precise calculations of these areas. Corrections must account for the spatial distribution of water, N, and N2O emissions in irrigated orchards. Random forest and structural equation modeling results indicate that N input is the primary factor influencing N2O emissions, while climate, soil characteristics, and other field management also play significant roles. Significant variations in emissions among different orchard types were observed, primarily attributed to differences in N input and fertilization methods. Average N2O emissions from peach and grape orchards (7.21 vs. 8.98kgN ha-1) are significantly greater than those from other orchards (3.02-4.87kgN ha-1). Furthermore, N fertilization exacerbated the disparity in N2O emissions between evergreen and deciduous orchards (4.02 vs. 6.06kgN ha-1). Three climate-smart strategies have been identified to mitigate the hotspot issue of N2O emissions from Chinese orchards and promote sustainable orchard development. In conclusion, with policy guidance and improved field management, China is well-positioned to lead in climate-smart orchard management practices and contribute to global climate change mitigation. Further research and innovation in orchard systems management will be crucial in achieving carbon neutrality and ensuring the long-term sustainability of orchard systems.
[Display omitted]
