为保护农业生产力，减少化肥施用是农业清洁和高质量发展的关键。基于东北三省825份玉米种植户的调研数据进行实证检验，探讨了农业生产外包对农户化肥减量的影响及其作用机制。研究发现：第一，农业生产外包显著减少了化肥施用量。在替换被解释变量、替换解释变量和考虑内生性问题后，结论依然稳健。第二，机制检验表明，服务规模连片化在农业生产外包与化肥减量之间存在正向调节作用。服务规模连片化会促进农户化肥减施，并在农业生产外包下影响农户化肥减施过程中发挥调节作用。第三，整地和播种施肥环节外包强化了农业生产外包的化肥减量效应，而田间管理和收割环节没有起到减少化肥施用量的效果。以上结论说明农户参与农业生产外包能够减少化肥施用量，而服务规模连片化起到调节作用，在不同环节中，整地和播种施肥环节有促进作用。

To protect agricultural productivity, reducing fertiliser application is the key to clean and high-quality agricultural development. Based on empirical tests of research data from 825 maize farmers in three northeastern provinces, we explored the impact of agricultural production outsourcing on farmers' fertilizer reduction and its mechanism of action. The study found that, firstly, agricultural production outsourcing significantly reduced fertiliser application. The findings remain robust after replacing the explanatory variables, replacing the explanatory variables and considering the endogeneity issue. Second, the mechanism test indicates that service scale serialisation has a positive moderating effect between agricultural production outsourcing and fertiliser reduction. Service scale serialisation promotes farmers’fertiliser reduction and plays a moderating role in influencing farmers’ fertiliser reduction under agricultural production outsourcing. Third, outsourcing of land preparation and sowing and fertiliser application reinforces the facilitating effect of agricultural production outsourcing in reducing fertiliser application, while field management and harvesting do not have the effect of reducing fertiliser application. The above findings suggest that farmers' participation in outsourcing of agricultural production can reduce fertiliser application, and that the scale of service delivery is moderated by the facilitating effect of land preparation and seeding and fertiliser application in the different segments.

国家自然科学基金项目（72103143；72373101）；国家社会科学基金项目（22&ZD083）；中国博士后科学基金项目（2024M762162）；广东省哲学社会科学规划项目（GD23XYJ81）