Effects of thinning on soil heterotrophic respiration of oak-pine mixed forests in Qinling Mountains
[Objective]This study,with an investigation of the effects of thinning on soil heterotrophic respiration in oak-pine mixed forests in the Qinling Mountains,is aimed to better understand the carbon loss caused by forest soil heterotrophic respiration under thinning treatments,providing a scientific basis for forest management decisions in the study area.[Method]The static chamber-gas chromatography technique was employed to monitor the variations of soil heterotrophic respiration flux in the growing season for the unthinned plots(4 replicates,ck)and the thinning plots(4 replicates)4 and 12 years ago(4 a and 12 a),respectively.The temperature sensitivities(Qio)of heterotrophic respiration were also calculated.[Result](1)There was a remarkable decrease in the soil microbial biomass carbon content(P＜0.05),but a significant increase in the the soil pH(P＜0.05)in both 4 a and 12 a compared to ck,while the decrease in the soil organic carbon content of 4 a after thinning was significant(P＜0.05).Generally,the soil physical and chemical index in 12 a were closer to that in the ck than the 4 a treatment.(2)The soil heterotrophic respiration during the growing season showed a"bimodal"pattern,and the peaks appeared in June and October,respectively.However the cumulative heterotrophic respiration increased after thinning but not significantly,with the order from large to small being 12 a＞4 a＞ck.(3)The soil temperature was significantly and exponentially correlated with the soil heterotrophic respiration(P＜0.05).The temperature sensitivities Q10 decreased after thinning,with the order from large to small being ck＞12 a＞4 a.[Conclusion]The soil temperature is a key factor affecting soil heterotrophic respiration in oak-pine mixed forests and the thinning treatment do not promote soil heterotrophic respiration of the oak-pine mixed forests in the growing season at the Qinling Mountains.[Ch,3 fig.2 tab.34 ref.]
southern slope of Qinlingforest tendingsoil organic carbon decompositionsoil respiration
万方数据
维普
