不同水位管理对恢复泥炭地土壤CO2、CH4排放的影响

泥炭地水文条件影响泥炭地生物地球化学循环，控制和维持着泥炭地生态系统的结构和功能，是泥炭地生态恢复的重要前提。然而，目前关于恢复泥炭地土壤碳排放对不同水位的响应尚不明确。以长白山区天然（NP）、退耕（DP）及实施不同水文管理的恢复泥炭地（低水位（LR）、高水位（HR）与高低交替水位（H-LR））为研究对象，采用静态箱-气相色谱法对研究区泥炭地进行生长季（6-10月）土壤CO₂、CH₄排放监测。结果表明：温度和水位变化是研究区泥炭地土壤CO₂、CH₄排放季节变化的主控因子。H-LR受水位控制的影响，生长季土壤CO₂排放速率波动剧烈，其它水位管理恢复区土壤CO₂排放速率呈单峰型排放模式，且均与近地表温度呈指数相关（P<0.05）。除HR外，土壤CO₂排放速率与水位呈显著负相关（P<0.05）。生长季，研究区HR土壤CH₄排放速率呈双峰型，H-LR与NP的土壤CH₄排放呈单峰型，与近地表温度呈指数相关（P<0.05），LR水位与CH₄排放速率显著正相关（P<0.05）。研究区不同水位管理恢复泥炭地土壤碳排放差异显著，虽然HR的土壤CO₂-C累积碳排放量显著低于其它水位恢复区，但其土壤CH₄-C累积碳排放量和综合增温潜势显著高于其它水位恢复区（P<0.05）。LR的累积碳排放量显著低于退化泥炭地，且其综合增温潜势最低。因此，建议在泥炭地恢复初期将低水位管理作为短期策略，以更好地恢复泥炭地碳汇功能，减弱其增温潜势。

Effects of different hydrologic managements on soil CO2 and CH4 emissions of the restored peatlands

The hydrological condition influences the biogeochemical cycles of peatlands and maintains the structures and functions of peatland ecosystems. Therefore, adopting appropriately hydrological management measures during restoration is important to the rapid recovery of ecological functions in peatlands. However, it is unclear how soil carbon emissions respond to different hydrologic managements. In this study, the effects of different hydrological managements, including low water level (LR), high water level (HR), and high-low alternating water level (H-LR), on soil CO₂ and CH₄ emissions of the restored peatlands during the growing season in Changbai Mountains were investigated. Results showed that air temperature and water level changes were the main factors affecting the seasonal variation of soil CO₂ and CH₄ emissions in the study area. As affected by water level control, soil CO₂ emission rate of H-LR fluctuated sharply during the growing season while showed a unimodal curve in other study areas, and were exponentially associated with air temperature (P<0.05). Soil CO₂ emission rates were significantly negatively correlated with water level (P<0.05) except HR. During the growing season, soil CH₄ emission rate of HR was bimodal while that of H-LR and NP was unimodal, and they were exponentially correlated with air temperature (P<0.05). The water level of LR was positively correlated with CH₄ emission rate (P<0.05). There were significant differences in soil carbon emissions among restored peatlands with different hydrologic managements (P<0.05). HR had the lowest cumulative CO₂-C emission, but it had the highest cumulative CH₄-C emission and warming potential (P<0.05). The soil cumulative carbon emission in LR was significantly lower than the degraded peatland and its warming potential was the lowest. Our study suggests that low water level management should be taken as a short-term strategy in the early stage of peatlands recovery to better restore the carbon sink function of peatlands and weaken warming potential.