南亚热带森林植被恢复演替中土壤有机碳组分及其稳定性  

Variations in the Fractions and Stabilization of Soil Organic Carbon with Forest Succession in Southern China

作　　者：陈小梅[1] 闫俊华[2] 林媚珍[1] 褚国伟[2] 吴建平[2] 张德强[2] 

机构地区：[1]广州大学地理科学学院,广东广州510006 [2]中国科学院华南植物园,广东广州510650

出　　处：《地球科学进展》2016年第1期86-93,共8页Advances in Earth Science

基　　金：国家自然科学基金青年科学基金项目"南亚热带地带性森林土壤有机碳形态结构对降水格局改变的响应"(编号:31400415);广东省普通高校青年创新人才项目"城乡梯度上亚热带森林土壤碳积累机理分析"(编号:2014KQNCX110)资助~~

摘　　要：以鼎湖山森林植被恢复演替过程中的松林(初期)、混交林(中期)和季风林(后期)为研究对象,通过测定其土壤总有机碳(TOC)、易氧化有机碳(ROC)和不易氧化有机碳(NROC)及凋落物13C-NMR分析,以期阐明森林植被恢复演替过程中土壤有机碳组分变化规律及其原因。结果表明:(1)3个森林土壤ROC含量差异不显著;由松林向季风林演替过程中,ROC占TOC的比例下降。松林新鲜凋落物层的烷氧基碳含量(57.03%)高于季风林(49.10%)和混交林(54.50%)。(2)3个森林土壤NROC含量差异显著,大小顺序为:季风林>混交林>松林。混交林和季风林凋落物半分解层和已分解层的惰性指数明显高于松林。TOC趋势与NROC一致。南亚热带森林由松林向季风林恢复演替过程中,土壤有机碳的稳定性增加,惰性有机碳的持续积累可能是季风林和混交林土壤TOC积累的一个重要过程。Soil Organic Carbon（ SOC） fractions play a critical role in the stabilization of SOC. It is essential to clarify the variations in SOC fractions along forest succession for predicting soil carbon（ C） source / sink capacity as forest develops. In the present study,we collected and analyzed soil samples in Total Organic Carbon（ TOC）content and the concentration of its Readily Oxidizable Organic Carbon（ ROC） and Non-Readily Oxidizable Organic Carbon（ NROC） fractions in a Pine Forest（ PF）,a pine and broadleaf Mixed Forest（ MF）,and an old-growth monsoon evergreen Broadleaf Forest（ BF） in the subtropical China. The three forests represent different successional stages of forest in southern China,with the PF being at the early,the MF at the middle and the BF at the climax stages,respectively. To clarify the reasons for why SOC fractions changed with forest succession,litterfalls in these forests were also collected to assay C functions by means of13 C Nuclear Magnetic Resonance（ NMR） analysis. Results showed that although there was no significant difference in the content of ROC among the three forests,the ratio of ROC to TOC in the PF was significantly higher than that in both of the BF and MF. This was likely due to the higher content of O-alkyl C in fresh litter in the PF than in the other two forests. Unlike ROC,however,NROC content was the highest in the BF,followed by the MF and then PF,which could be attributed to the lower recalcitrance index in the partly-decomposed and decomposed litterfall layers in the PF than in the MF and PF. Finally,TOC concentration was significantly the highest in the climax BF,the lowest in the youngest PF,and in between in the MF. Our results suggest that the accumulation of NROC,which is the recalcitrant fraction of SOC,may be the major reason for why forests at the middle and late stages（ i. e.,the MF and BF,respectively） maintain higher TOC content and Organic Carbon（ OC） stabilization in soils.

关 键 词：森林恢复演替 土壤碳积累 土壤碳固持 有机碳组分 南亚热带森林 

分 类 号：P935[天文地球—自然地理学] Q148[生物学—生态学]