Most nitrogen (N) lost to the environment from grazed grassland is produced as a result of N excreted by livestock, released in the form of nitrous oxide (N₂O) emissions, nitrate leaching and ammonia volatilisation. In addition to the N fertiliser applied, excreta deposited by grazing livestock constitute a heterogeneous excess of N, creating spatial hotspots of N losses. This study presents a yearlong N₂O emissions map from a typical intensively managed temperate grassland, grazed periodically by a dairy herd. The excreta deposition mapping was undertaken using high-resolution RGB images captured with a remotely piloted aircraft system combined with N₂O emissions measurements using closed statics chambers. The annual N₂O emissions were estimated to be 3.36 ± 0.30 kg N₂O–N ha⁻¹ after a total N applied from fertiliser and excreta of 608 ± 40 kg N ha⁻¹ yr⁻¹. Emissions of N₂O were 1.9, 3.6 and 4.4 times lower than that estimated using the default IPCC 2019, 2006 or country-specific emission factors, respectively. The spatial distribution and size of excreta deposits was non-uniform, and in each grazing period, an average of 15.1% of the field was covered by urine patches and 1.0% by dung deposits. Some areas of the field repeatedly received urine deposits, accounting for an estimated total of 2410 kg N ha⁻¹. The method reported in this study can provide better estimates of how management practices can mitigate N₂O emissions, to develop more efficient selective approaches to fertiliser application, targeted nitrification inhibitor application and improvements in the current N₂O inventory estimation.

放牧草地向环境损失的大部分氮 (N) 是由牲畜排泄的氮产生的，以一氧化二氮 (N ₂ O) 排放、硝酸盐浸出和氨挥发的形式释放。除了施氮肥外，放牧牲畜的排泄物构成了不均匀的氮过剩，造成了氮损失的空间热点。本研究展示了一个典型的集约化管理温带草原一年的 N ₂ O 排放图，奶牛群定期放牧。使用遥控飞机系统捕获的高分辨率 RGB 图像结合使用封闭静力室的 N ₂ O 排放测量进行排泄物沉积测绘。年度 N ₂在从肥料和排泄物中施用的总氮量为 608 ± 40 kg N ha ^-1  yr ^-1之后，O 排放量估计为 3.36 ± 0.30 kg N ₂ O–N ha ^-1。N ₂ O 的排放量分别比使用默认 IPCC 2019、2006 或国家特定排放因子估计的低 1.9、3.6 和 4.4 倍。粪便沉积物的空间分布和大小不均匀，在每个放牧时期，平均有15.1%的田地被尿斑覆盖，1.0%的土地被粪便沉积物覆盖。该田地的一些区域反复出现尿液沉积物，估计总数为 2410 kg N ha ^-1. 本研究报告的方法可以更好地估计管理实践如何减少 N ₂ O 排放，从而开发更有效的施肥选择性方法、有针对性的硝化抑制剂应用以及改进当前的 N ₂ O 库存估算。