漓江流域岩溶区檵木群落不同恢复阶段凋落物分解初期动态

摘要

Litter,as an essential component of the forest ecosystem,plays an important role in maintaining site fertility,sequestering carbon,and nurturing soil biodiversity.In order to explore litter decomposition at different restoration stages of Loropetalum chinense communities in the karst area of the Lijiang river watershed,we used the litter bag method to study the initial dynamic of litter decomposition.The results showed that after 1 year of decomposition,litter mass loss of L.chinense communities followed the order shrub stage＞ shrub-tree stage＞tree stage.The predicated period of litter decomposition 50％ and 95％ for shrub stage,shrub-tree stage and tree stage was 1.28a and 5.54a,1.38a and 5.97a,as well as 1.41a and 6.09a,respectively.After 1 year of decomposition,the content of organic carbon had the increasing trend in shrub stage and shrub-tree stage,and had the declining trend in tree stage.There was an overall increase in the initial content of N and cellulose at each restoration stage.However,the initial content of P in the shrub and tree stages generally declined compared with that in the shrub-tree stage.In addition,we found that the organic carbon content increased in the shrub and shrub-tree stages and declined in the tree stage.In addition,the lignin content in the shrub and shrub-tree stages generally increased while in the tree stage it generally declined.There was a significant correlation between litter decomposition rate and organic carbon,N,P,C/P,N/P contents in the shrub stage;between litter decomposition rate and N,lignin/N in the shrub-tree stage;and between litter decomposition rate and N,cellulose,C/N,lignin/N in the tree stage.%为探究漓江流域岩溶区檵木群落不同恢复阶段凋落物的分解情况,运用凋落物袋法研究其凋落物分解初期动态.结果表明:经过1a的分解,檵木群落凋落物失重大小顺序为:灌木阶段＞乔灌阶段＞乔林阶段.檵木群落灌木阶段、乔灌阶段和乔林阶段凋落物分解50％所需的时间分别为1.28a、1.38a、1.41a,分解95％所需的时间分别为5.54a、5.97a和6.09a.经过1a的分解,凋落物养分动态变化为:灌木阶段和乔灌阶段C含量总体上升,乔林阶段C含量总体下降;3个恢复阶段N和纤维素含量总体上升;灌木阶段和乔林阶段P含量总体下降,乔灌阶段P含量总体上升;灌木阶段木质素含量总体上升,而乔灌阶段和乔林阶段木质素含量总体下降.相关分析表明,灌木阶段凋落物分解速率分别与C,N,P,C/P,N/P之间呈显著或极显著相关性,乔灌阶段凋落物分解速率与N和木质素/N之间呈显著或极显著相关性,乔林阶段凋落物分解速率分别与N,纤维素、C/N和木质素/N之间呈显著或极显著相关性.