短期增温对内蒙古大青山油松人工林土壤温室气体通量的影响

Effect of Short-term Warming on Soil Greenhouse Gas Fluxes in Pinus tabulaeformis Plantations in Daqingshan,Inner Mongolia

[目的]揭示内蒙古大青山土壤温室气体通量的变化趋势和影响,为温室气体在森林生态系统的排放机制和影响因素提供理论基础。[方法]利用OTC(开顶式增温箱)模拟大气温度升高,采用静态箱-气相色谱法野外原位观测土壤温室气体(CO_(2)、CH_(4)、N_(2)O)通量的日动态、季节动态及年际动态的变化规律。[结果]模拟增温的条件下,5、10、20、40 cm土层土壤年均增温分别为1.13、2.16、1.21、0.70℃,大气年均增温0.61℃;增温处理下,5、10、20 cm土层土壤年均湿度分别降低4.64%、3.50%和8.43%,40 cm土层土壤湿度平均增加1.87%,大气湿度平均降低5.93%。增温降低了土壤有机碳、碱解氮、全氮、硝态氮含量、碳氮比,促进了铵态氮的转化。增温处理抑制了CO_(2)通量排放,生长季CO_(2)通量降低了25%。土壤CH_(4)通量在生长季表现为大气CH_(4)的汇,增温状态下的CH_(4)通量平均吸收值略高于CK,一定程度上促进了CH_(4)通量吸收。土壤N_(2)O通量在生长季表现为大气N_(2)O的源,生长季无显著差异,增温对N_(2)O排放通量具有一定促进作用,但影响较小。[结论]该研究结果可为半干旱森林土壤温室气体通量排放研究提供参考依据。

[Objective]To reveal the changing trend and influence of soil greenhouse gas flux in Daqing Mountain,Inner Mongolia,and provide a theoretical basis for the emission mechanism and influencing factors of greenhouse gases in the forest ecosystem.[Method]In this experiment,OTC(open top heating chamber)was used to simulate the atmospheric temperature rise,and static chamber gas chromatography was used to observe the diurnal,seasonal and interannual dynamics of soil greenhouse gas(CO_(2),CH_(4),N_(2)O)fluxes in situ.[Result]Under the condition of simulated warming,the average annual temperature of soil 5,10,20 and 40 cm was 1.13,2.16,1.21 and 0.70℃respectively,and the average annual temperature of atmosphere was 0.61℃;under the warming treatment,the soil humidity at 5,10 and 20 cm decreased by 4.64%,3.50%and 8.43%annually,the soil humidity at 40 cm increased by 1.87%on average,and the atmospheric humidity decreased by 5.93%on average.Warming reduced soil organic carbon,alkali hydrolyzable nitrogen,total nitrogen,nitrate nitrogen,C/N content,and promoted the transformation of ammonium nitrogen.The warming treatment inhibited the emission of CO_(2)flux,and the CO_(2)flux in the growing season decreased by 25%.The soil CH_(4) flux in the growing season showed as a sink of atmospheric CH_(4),and the average absorption value of CH_(4) flux in the warming state was slightly higher than that in the control group,which promoted the absorption of CH_(4) flux to a certain extent.The soil N_(2)O flux is the source of atmospheric N_(2)O in the growing season,and there is no significant difference in the growing season.The warming has a certain promotion effect on N_(2)O emission flux,but the influence is small.[Conclusion]The research results can provide a reference for researchers studying greenhouse gas emissions from semi-arid forest soil.