Effect of fire disturbance and black carbon input on soil methane flux during growing season of Pinus tabulaeformis forest
[Objective]As an important disturbance factor in forest ecosystems,fire disturbance can have drastic effects on both the nature and structure of forest soils,which are the most important sink for atmospheric CH4,so the effects of fire disturbance on CH4 fluxes from forest soils cannot be ignored.At the same time,a large amount of black carbon is produced after fire due to incomplete combustion of vegetation.Black carbon is an aromatic compound with a porous structure,which can affect soil porosity,pH and other physicochemical properties after entering the soil and thus change the soil structure,so it is often used as a soil conditioner to reduce CH4 emissions from agricultural soils,but,there is a lack of clarity as to whether post-fire black carbon inputs can affect forest soil CH4 fluxes and the factors influencing them.[Method]In this study,we investigated the dynamic changes of soil CH4 fluxes and influence factor after fire disturbance and post-fire black carbon inputs using Pinus tabulaeformis forest in Shenyang's Checkboard Mesa as the research object.[Result]1)The fire disturbance increased soil CH4 fluxes during the growing season in P.tabulaeformis forests,with soil CH4 fluxes in the heavily burned sample plots being significantly higher than those in the control sample plots and the lightly burned sample plots.2)Black carbon input decreased soil CH4 fluxes during the growing season in P.tabulaeformis forests,and the magnitude of the decreased in soil CH4 fluxes increase with the increase in the amount of black carbon input.3)The fire intensity had a direct and highly significant positive effect on soil CH4 fluxes,with a direct and highly significant positive effect on soil CH4 fluxes,which explaining 46.9%(P＜0.001);Black carbon input had a direct significant negative effect on soil CH4 flux,explaining 8.8%(P＜0.05);And MBC and MBN hada direct highly significant positive effect on soil,explaining 29.0%and 49.3%,respectively(P＜0.001).[Conclusion]Fire disturbance significantly increase soil CH4 fluxes,black carbon input can mitigate the effect of fire disturbance on soil CH4 fluxes to a certain extent,and that fire disturbance and black carbon input affect soil CH4 fluxes mainly by changing microbial biomass.The study provides a theoretical basis for how to reduce post-fire greenhouse gas emissions and thus improve the ecological environment of fire sites as well as post-fire understory.
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