Optimising nitrogen (N) management improves soil fertility and reduces negative environmental impacts. Mineral N fertilizers are of key importance in intensive conventional farming (CF). In contrast, organic farming (OF) is highly dependent on closed nutrient cycles, biological N fixation and crop rotations. However, both systems need to minimise N balances and maximise nitrogen-use efficiency (NUE). NUE of organic and conventional crop production systems was evaluated in three regions in Germany by analysing N input, N output and N balance of 30 pairs of one OF and one CF farm each from the network of pilot farms for the period 2009–2011; indicators were calculated using the farm management system REPRO. CF had higher N input in all farm pairs. In 90% of the comparisons, N output of CF was higher than OF, in 7% it was the same and in 3% lower. NUE was higher in 60% of the OF, the same in 37% and lower in only 3%. The NUE of crop production in OF was 91% (arable farms: 83%; mixed/dairy farms: 95%) and the NUE in CF was 79% (arable farms: 77%; dairy farms: 80%). N balance was lower in 90% of the OF. The yearly average N balance was four times higher in CF (59 kg N ha⁻¹ a⁻¹) than in OF (15 kg N ha⁻¹ a⁻¹). The results show a huge individual variability within OF and CF. Organic mixed/dairy farms had the lowest N balances and the highest NUE. A further expansion of OF area can help to reduce high N balances and increase the NUE of crop production.

优化氮（N）管理可以改善土壤肥力并减少负面的环境影响。矿物氮肥在传统的集约耕作（CF）中至关重要。相反，有机耕作（OF）高度依赖于封闭的养分循环，生物固氮和作物轮作。但是，两个系统都需要最小化氮平衡并最大化氮利用效率（NUE）。在德国的三个地区，通过分析2009-2011年试点农场网络中30对一对OF和一个CF农场的氮输入，氮产量和氮平衡，对有机和常规作物生产系统的NUE进行了评估；使用农场管理系统REPRO计算指标。在所有农场对中，CF的氮输入较高。在90％的比较中，CF的氮输出高于OF，在7％中相同，而在3％以下。NUE在OF的60％中较高，在37％中相同，仅3％中较低。OF的农作物NUE为91％（可耕种的农场：83％；混合/奶牛场：95％），CF的NUE为79％（可耕种的农场：77％；奶牛场：80％）。氮平衡在OF的90％中较低。CF的年平均N平衡高出四倍（59 kg N ha^-1  a ^-1）比OF中的（15 kg N ha ^-1  a ^-1）。结果表明，OF和CF内的个体差异很大。有机混合/奶牛场的氮平衡最低，NUE最高。OF面积的进一步扩大可以帮助减少高氮平衡并提高作物产量的NUE。