Context In grazed pasture systems, most nitrogen (N) losses arise from N deposited in the form of ruminant excreta patches. However, during winter, when grassland stocking rate and soil nitrous oxide (N2O) emissions are expected to be low, N2O fluxes from excreta patches could be considered negligible for the calculation of the total emissions. Aims The aims of the study were to quantify and compare N2O winter emissions in soils with and without grazing and to study some drivers of N2O emission during a low-temperature period. Methods The experiment was performed in the Flooding Pampa, Argentina, in a completely randomised design with repeated measures over time. The treatments were urine, faeces, and control without excreta addition. During winter, 20 gas samplings were made for each treatment, and the results of N2O fluxes were extrapolated to 1 ha. Key results Daily N-N2O emissions of the control were 0–10 mg/m2.h. The N-N2O emissions from the urine patches were higher (P < 0.05) than those from faeces and control treatments, with average respective treatment values of 26.13, 5.35 and 2.88 µg N-N2O/m2.h. The N-N2O emissions increased after urine application and fluxes from this treatment were intensified after rainfall. The cumulative N2O emission per chamber was almost 10 times higher in the urine treatment than in the faeces and control treatments. Conclusion The air temperature influenced N2O emissions. The accumulated N2O per hectare arising from animal deposition was <5% greater than in the control. Implications Although the contribution of animal excreta to soil N2O emissions seems to be low, it could be of relevance once extrapolated to the total area under grazing on the Argentinean pampas (principally Flooding Pampa) where the low-temperatures period is at least 15% of the year.

中文翻译：

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阿根廷潘帕草原直接放牧肉类生产系统的冬季土壤 N2O 排放

背景 在放牧牧场系统中，大部分氮 (N) 损失来自以反刍动物排泄物斑块形式沉积的氮。然而，在冬季，当草地放养率和土壤一氧化二氮 (N2O) 排放量预计较低时，排泄物斑块中的 N2O 通量在计算总排放量时可以忽略不计。目的 本研究的目的是量化和比较有和没有放牧的土壤中的 N2O 冬季排放，并研究低温期间 N2O 排放的一些驱动因素。方法 该实验在阿根廷的洪泛区进行，采用完全随机的设计，随着时间的推移重复测量。处理是尿液、粪便和不添加排泄物的对照。在冬季，每个处理进行了 20 次气体采样，N2O 通量的结果外推到 1 公顷。主要结果 对照的每日 N-N2O 排放量为 0–10 mg/m2.h。尿液斑块的 N-N2O 排放量高于粪便和对照处理的 N-N2O 排放量（P < 0.05），各自的平均处理值为 26.13、5.35 和 2.88 µg N-N2O/m2.h。应用尿液后 N-N2O 排放量增加，降雨后这种处理的通量增加。尿液处理中每室的累积 N2O 排放量几乎是粪便处理和对照处理中的 10 倍。结论 气温影响 N2O 排放。由动物沉积引起的每公顷累积 N2O 比对照高 <5%。影响 虽然动物排泄物对土壤 N2O 排放的贡献似乎很低，