Agricultural production is often accompanied by nitrogen (N) losses causing negative environmental effects. In order to assess dairy farms N management, appropriate indicators based on robust farm data need to be addressed. This study investigated N balance and N use efficiency (NUE) as a function of grazing intensity on specialized dairy farms in northwestern Germany. For that, 30 farms were grouped according to pasture management from full grazing to zero grazing: >10 h in group 1, 6 to 10 h in group 2, <6 h in group 3, and group 4 without pasture access. Based on multiple farm data, substance flow analysis was carried out. Subsequently, the data were analyzed according to the relevant indicators N surplus and NUE on feed-, field- and farm-level. The results revealed N surpluses on all farms, with the average N surplus tending to decrease from 259 to 179 kg N ha⁻¹, and farm-NUE to increase from 40 to 50 %, from full grazing to zero grazing management systems. There were considerable differences between the N balances calculated in this study and those reported by farms as part of statutory net N soil surface balance reporting under the German regulatory law. In conclusion, the N indicators were suitable to compare farm performance among and within different dairy farming systems. When comparing indicator values there is a need to consider the methodology applied, the system boundaries set, and the origin and quality of data used.

农业生产经常伴随着氮（N）的流失，对环境造成负面影响。为了评估奶牛场的氮管理，需要处理基于可靠的奶牛数据的适当指标。这项研究调查了德国西北部专业奶牛场的氮平衡和氮利用效率（NUE）与放牧强度的关系。为此，根据牧场管理，将30个农场从完全放牧归为零放牧：第1组> 10 h，第2组6至10 h，第3组和第4组不超过6 h，没有牧场。基于多个农场数据，进行了物质流分析。随后，根据饲料，田间和农场一级的相关指标N过剩和NUE对数据进行了分析。结果显示所有农场都有N剩余，^-1，并且农场的NUE从40％增加到50％，从完全放牧管理系统变为零放牧管理系统。在这项研究中计算出的氮平衡值与农场报告的氮平衡值之间存在相当大的差异，这是根据德国监管法作为法定净氮土壤表层平衡报告的一部分。总之，N指标适合比较不同奶牛养殖系统之间和内部的农场绩效。比较指标值时，需要考虑所采用的方法，系统边界集以及所用数据的来源和质量。