Abstract Nitrogen (N) surplus is an important environmental problem on the island of Ireland (Northern Ireland and the Republic of Ireland), and the dairy sector has been identified as contributing more to this problem compared to other agricultural sectors. As a result, there has been increased demand for efficient policy measures to improve the economic and environmental performance of dairy farms in the region. In this study, we employed the positive mathematical programming (PMP) optimization modelling framework to simulate the economic and environmental impact of two alternative agri-environmental policy instruments on different dairy farm types. Specifically, the study considers the effects of an N surplus tax and an agri-environmental nutrient application standard on the production performance and N surplus of representative dairy farms using scenario analyses. The results of the analyses showed that the effects of the agri-environmental policy instruments vary across the two countries and clusters of dairy farms, resulting in clear differential effects on farm structure and N surpluses. The study concluded that in situations where the nutrient surplus is already high, as with the large farms clusters in this study, the use of manure application standards will be more effective in limiting nutrient surplus to soils compared to the use of nutrient surplus tax.

中文翻译：

---

替代农业环境政策工具对代表性奶牛场生产绩效和氮肥过剩的影响分析

摘要 氮 (N) 过剩是爱尔兰岛（北爱尔兰和爱尔兰共和国）的一个重要环境问题，与其他农业部门相比，乳制品部门已被确定对这一问题的贡献更大。因此，对有效政策措施的需求不断增加，以改善该地区奶牛场的经济和环境绩效。在本研究中，我们采用正数学规划 (PMP) 优化建模框架来模拟两种替代农业环境政策工具对不同奶牛场类型的经济和环境影响。具体来说，该研究使用情景分析考虑了氮盈余税和农业环境养分应用标准对代表性奶牛场的生产绩效和氮盈余的影响。分析结果表明，农业环境政策工具对两国和奶牛场集群的影响各不相同，导致对农场结构和氮盈余的影响明显不同。该研究得出的结论是，在养分过剩已经很高的情况下，如本研究中的大型农场集群，与使用养分过剩税相比，使用粪便施用标准将更有效地限制土壤养分过剩。分析结果表明，农业环境政策工具对两国和奶牛场集群的影响各不相同，导致对农场结构和氮盈余的影响明显不同。该研究得出的结论是，在养分过剩已经很高的情况下，如本研究中的大型农场集群，与使用养分过剩税相比，使用粪便施用标准将更有效地限制土壤养分过剩。分析结果表明，农业环境政策工具对两国和奶牛场集群的影响各不相同，导致对农场结构和氮盈余的影响明显不同。该研究得出的结论是，在养分过剩已经很高的情况下，如本研究中的大型农场集群，与使用养分过剩税相比，使用粪便施用标准将更有效地限制土壤养分过剩。