Emissions of N₂O from two dairy farms with different grazing intensity responded non-linearly to increasing soil nitrate availability and total rainfall. Higher N₂O emissions were observed immediately after grazing, due to the possible increased incidence of N deposition from animal excreta, increased soil compaction and low plant N uptake. The spatial distribution of N₂O fluxes and soil nitrate contents reflected the effect of animal treading and excreta N deposition with N₂O fluxes in the proximity of field gateways 11 times higher than the field average. Three years average annual N₂O emissions were 6 times higher (9.3 ± 2.6 kg N₂O-N ha⁻¹ y⁻¹) in the high grazing intensity farm than in the low grazing intensity farm (1.6 ± 0.2 kg N₂O-N ha⁻¹ y⁻¹). This corresponded to 2% and 0.9% of the fertiliser N inputs lost as N₂O for the high and low intensity farm, respectively. The GHG intensity (N₂O emitted per kg of fat and protein corrected milk FPCM) for the intensive system was only almost two times higher than the non-intensive system (0.12 vs 0.08 kg CO₂-eq per kg FPCM y⁻¹ for the high and low intensity system, respectively). The high occurrence of N load hotspots near animal gateways in this study underlines the necessity to account for the spatial N variation in dairy grazing systems. Integrating the spatial management of N loads into improved farming practice has therefore significant scope to reduce N₂O emissions and N losses from dairy grazing systems.

中文翻译：

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牧场式乳制品系统中N 2 O排放的现场规模管理和环境驱动因素

两个放牧强度不同的奶牛场的N ₂ O排放对土壤硝态氮有效性和总降雨量的增加呈非线性响应。放牧后立即观察到较高的N ₂ O排放量，这是由于动物排泄物中N沉积的可能性增加，土壤密实性增加和植物N吸收低。N ₂ O通量和土壤硝酸盐含量的空间分布反映了田间通道附近N ₂ O通量的动物踩踏和粪便N沉积的影响，其高出田间平均水平11倍。三年的年均N ₂ O排放量高出6倍（9.3±2.6 kg N ₂ O-N ha ^-1 y^-1）高放牧强度电场比低强度放牧场中在（1.6±0.2千克氮₂ O-N公顷^-1 ý ^-1）。在高强度和低强度农场，这分别相当于肥料氮输入损失的2％和0.9％，作为N ₂ O损失。强化系统的GHG强度（每千克经脂肪和蛋白质校正的牛奶FPCM排放的N ₂ O）仅比非强化系统高几乎两倍（每公斤FPCM y ^-1的CO ₂当量为0.12 vs 0.08 kg CO ₂当量）分别用于高强度和低强度系统）。在这项研究中，动物通道附近N负载热点的高发生率突显了必须考虑奶牛放牧系统中空间N的变化。因此，将氮负荷的空间管理整合到改善的耕作方式中，对于减少N ₂ O排放和奶牛放牧系统造成的氮损失具有重要的意义。