不同间伐恢复年限对秦岭松栎混交林土壤甲烷通量的影响OA

[Objective]This study aims to elucidate the temporal effects of thinning on soil methane(CH4)fluxes in mixed pine-oak forests in the Qinling Mountains,providing scientific evidence for optimizing forest management strategies to regulate soil CH4 fluxes.[Method]A chronosequence approach was adopted to examine three treatment groups:unthinned(CK),five-year post-thinning(5a),and 13-year post-thinning(13 a).Soil CH4 fluxes were monitored monthly using the static chamber-gas chromatography approach.Statistical analyses incorporated one-way ANOVA for treatment effects,repeated measures ANOVA for temporal variations,and linear regression to identify environmental drivers.[Result]Thinning significantly modified soil properties:compare with CK,soil temperature increased by 2.73 ℃ in 5a plots(P＜0.05),while pH in 13 a plots increased 0.32(P＜0.05)and NH4-N content in the 13 a plots decreased 2.86 mg/kg(P＜0.05).while other soil physicochemical properties before and after thinning had no significant changes.Recovery duration induced progressive changes:soil water content increased by 10.21％;soil temperature decreased by 3.08 ℃;and TP mass fraction increased by 0.21 g/kg.Seasonal CH4 flux dynamics showed peak absorption in July for all treatments.Thinning initially enhanced CH4 oxidation capacity(5 a vs CK,P＜0.05),which reverted to pre-treatment levels by 13 a(13 a vs CK,P＞0.05).Regression analysis identified soil temperature and moisture as primary controls,which for every 1 ℃ increase in soil temperature,the soil CH4 uptake rate increased by 0.09-0.22 mg/(m2·d).Conversely,a 1％rise in soil moisture content reduced the CH4 uptake rate by 0.03-0.10 mg/(m2·d).Notably,stands with shorter post-thinning recovery duration(5 a)exhibited higher sensitivity to both moisture content and temperature variations.[Conclusion]Thinning temporarily enhances soil CH4 oxidation capacity through microclimate modification,specifically via soil temperature increasing by 2.73 ℃ in early post-thinning stages(5a).The positive effect of CH4 uptake diminishes with canopy recovery(13 a),suggesting rotational thinning interval below 13 years can could sustain soil CH4 sink functionality.