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).