Abstract Grazing exclusion of grasslands has traditionally been considered to reduce nitrogen inputs and decrease nitrous oxide (N2O) emissions. However, recent studies have shown that grazing exclusion may increase N2O emissions because of freeze-thaw cycles. In this study, year-round N2O fluxes (including high-frequency measurements during the freeze-thaw cycles) were measured in three sites that included long-term grazing exclusion (ungrazed since 1979, UG79), short-term grazing exclusion (ungrazed since 1999, UG99), and continuously grazed (CG), in Inner Mongolia grassland. The results showed that: 1) across the entire period of observations, mean annual N2O fluxes were the highest at UG99 (12.2 μg m−2 h-1), followed by CG (8.6 μg m−2 h-1) and UG79 (7.5 μg m−2 h-1); 2) during spring freeze-thaw cycles, cumulative N2O emissions were significantly higher at UG99 than UG79 and CG (P

中文翻译：

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内蒙古典型草原冻融循环期间禁牧对一氧化二氮排放的影响

摘要 传统上，草原的放牧排除被认为可以减少氮输入并减少一氧化二氮 (N2O) 排放。然而，最近的研究表明，由于冻融循环，排除放牧可能会增加 N2O 排放。在这项研究中，在三个地点测量了全年 N2O 通量（包括冻融循环期间的高频测量），包括长期放牧排除（自 1979 年以来未放牧，UG79）、短期放牧排除（自 1979 年以来未放牧） 1999年，UG99），连续放牧（CG），在内蒙古草原。结果表明：1）在整个观测期间，年均 N2O 通量在 UG99（12.2 μg m-2 h-1）最高，其次是 CG（8.6 μg m-2 h-1）和 UG79（ 7.5 μg m−2 h-1)；2) 在春季冻融循环中，