良种补贴政策的环境效应研究

以小麦良种补贴政策为例，将单位面积化肥施用量作为环境效应评估的代理变量，基于市级农业数据构建了双重差分模型，量化了政策实施导致的单位面积化肥施用量的变化，进而评估化肥施用量变化导致的农户种植成本、温室气体排放和社会碳成本的变化.结果表明，该政策实施使单位面积化肥施用量下降了5.9%，农户种植成本减少了139.42元/hm²，温室气体排放减少了822.06kg CO₂e/hm²，社会碳成本减少了301.91元/hm²，充分补偿了良种补贴的财政支出.建议未来农业补贴政策的制定、改进及推广应充分考虑其潜在的环境影响，以加强农业增产和环境效益的协同.

Environmental effects of improved seed variety subsidy policy

In this study, the wheat improved seed variety subsidy was taken as an example and the fertilizer application per unit area was used as a proxy variable to assess the environmental effects. Based on relevant agricultural data at the municipal level, a difference-in-differences model was constructed to quantify the changes in fertilizer application per unit area resulting from policy implementation. After that, the changes in planting costs, greenhouse gas emissions and social carbon costs due to changes in fertilizer application were estimated. The results showed that the policy had great environmental benefits, with the implementation of the policy resulting in a reduction of 5.9% in fertilizer application per unit area, a reduction of 139.42CNY/hm² in planting costs, a reduction of 822.06kg CO₂e/hm² in greenhouse gas emissions and a reduction of 301.91CNY/hm² in social carbon costs, fully compensating for the financial expenditure on the subsidy. The potential environmental impact should be taken into account in the development, improvement and extension of agricultural subsidy policies in the future, in order to enhance synergies between increased agricultural production and environmental benefits.