艾比湖湿地季节性冻融土壤温室气体排放规律研究

利用静态箱–气象色谱法对2015年11月—2016年3月艾比湖湿地季节性冻融期土壤温室气体进行观测. 结果表明:季节性冻融期裸地土壤CO₂表现为汇、芦苇和柽柳土壤CO₂表现为源；芦苇、柽柳和裸地土壤CH₄表现为汇，而N₂O表现为源；芦苇、柽柳和裸地土壤温室气体最低值均出现在冻结期（11月—次年2月）且为负通量；不同植被类型下土壤CO₂在融化期（3月末）出现排放峰值，而土壤CH₄和N₂O在冻融交替期(3月初)出现排放峰值；在整个观测期，芦苇和柽柳土壤CO₂、CH₄和N₂O排放峰值高于裸地；温度对季节性冻融期土壤CO₂和N₂O影响显著，均达到显著正相关（P<0.05），土壤温度能解释芦苇、柽柳和裸地土壤CO₂通量的77%～88%； 土壤质量含水量对土壤CH₄和N₂O影响均达到显著正相关关系（P<0.05），土壤质量含水量能解释芦苇、柽柳和裸地CH₄和N₂O通量的25%～46%和41%～69%. 表明在干旱区季节性冻融期，温度变化对不同植被类型下土壤CO₂影响较大，而在冻融交替期水分变化对CH₄和N₂O通量影响显著. 芦苇、柽柳和裸地土壤呼吸Q₁₀值分别为2.37，2.58和2.33，不同植被类型基于100 a尺度，土壤温室气体全球增温潜势由大到小依次为芦苇（569.67 kg·hm–2）、柽柳（152.09 kg·hm–2）、裸地（–861.50 kg·hm–2）. 

Greenhouse gas emission from seasonal frozen-thawed soil in Ebinur Lake wetland

Static box-meteorological chromatography was used to examine soil greenhouse gas emission in seasonal freezing-thawing period of Ebinur Lake wetland arid areas from November 2015 to March 2016. CO₂ of bare soil was found to be the sink, CO₂ of reed and tamarisk the source, CH₄ of reed, tamarisk and bare soil the sink, N₂O the source. The lowest value of greenhouse gas in reed, tamarisk and bare soil was found to appear in the freezing period (November–February) with a negative flux. Under different vegetation types, soil CO₂ emission was found to peak in thawing period (late march), while soil CH₄ and N₂O emissions peak in freezing–thawing alternate period (early march). During the observation period, emission peaks of CO₂, CH₄ and N₂O in soil of reed and tamarisk chinensis were found higher than bare land. Temperature was found to have significant influence on soil CO₂ and N₂O in seasonal freezing-thawing period, both with significant positive correlation ( P<0.05). Soil temperature explained 77%-88% of the CO₂ flux of reed, tamarisk and bare soil. The soil moisture content was found significantly positively correlated with soil CH₄ and N₂O ( P<0.05). Soil moisture content explained 25%-46% and 41%-69% of CH₄ and N₂O fluxes of reed, tamarisk and bare land. Temperature change was found to have a great impact on soil CO₂ in different vegetation types, while water change in freezing–thawing alternate period was found to have a significant impact on CH₄ and N₂O flux in the seasonal freezing-thawing period in arid areas. Respiratory Q10 values of reed, tamarisk and bare soil were found to be 2.37, 2.58 and 2.33, respectively. Global warming potential of different vegetation types based on 100-year scale of soil greenhouse gas was found to be: reed (569.67 kg·hm–2) > tamarisk (152.09 kg·hm–2) > bare land (–861.50 kg·hm–2).