冻融交替对长白山不同林型土壤两种温室气体排放的影响

以长白山5种林型土壤(硬阔叶林、红松阔叶林、次生白桦林、长白松林和蒙古栎林)为对象,利用原位培养连续取样法研究了冻融过程中5种林型土壤CO₂和N₂O排放特征及相关机理。结果表明:冻融期5种林型土壤是CO₂和N₂O的源。次生白桦林和红松阔叶林土壤CO₂和N₂O的平均通量显著高于其他3种林型。除硬阔叶林外,各林型土壤CO₂通量与土壤含水量间存在显著负相关,但不同林型的土壤CO₂排放对水分敏感性差异较大;除硬阔叶林外,各林型土壤N₂O通量与土壤含水量间存在显著正相关,但水分敏感性因林型而异。5种林型土壤CO₂和N₂O排放通量均与土壤表层温度呈二次函数关系。

Effects of freeze-thaw process on the emission of two greenhouse gases from different forest soils in Changbai Mountain

We examined the emission of CO₂ and N₂O from soils of five forest types(hardwood broad-leaved forest,Korean pine broad-leaved forest,secondary birch forest,Changbai pine forest and Mongolian oak forest)in the process of freeze-thaw by in situ continuous sampling.The results showed that soils from all the forest types were CO₂ and N₂O source during freeze-thaw season.The average flux of CO₂ and N₂O for secondary birch forest and Korean pine broad-leaved forest soils were significantly higher than that of other forest types.Except for the hardwood broadleaved forest,there was a significant negative correlation between CO₂ flux and soil water content in the forest soils.The water sensitivity of soil CO₂ emissions varied greatly among different forest types.There was a significant positive correlation between soil N₂O flux and soil water content in all forest types except the hardwood broad-leaved forest.The soil CO₂ and N₂O emission fluxes in five forest types were related to the temperature of surface soils by quadratic function.