Effect Of Stands At Different Stages On Litter Decomposition During Expansion Of Phyllostachy Edulis

The expansion of Phyllostachys edulis is a sensitive ecological problem.In recent years,because of its strong ability to expand the whip,the expansion of Phyllostachys edulis into the surrounding forest(evergreen broad-leaved forest)has appeared in Zhejiang,Jiangxi,Hunan and other places.The expansion of Phyllostachys edulis into evergreen broad-leaved forest will cause changes in vegetation composition and forest environment,which may change litter decomposition.Studying litter changes is of great significance for understanding the impact of Phyllostachys edulis expansion on carbon cycle and nutrient release.At present,there are few studies on the rate of litter decomposition and litter carbon and nitrogen release caused by the expansion of Phyllostachys edulis to broad-leaved forest.In this study,the pure Moso bamboo forest,mixed Moso bamboo and broad-leaved forest of Moso bamboo were taken as the research objects during the expansion process from Moso bamboo forest to surrounding broad-leaved forest,using the method of decomposition bags,set up in each stand soil with both 100 mesh and 13 purpose litter decomposition bag.The litter in decomposition bags were pure bamboo leaf,the ratio of 3:1 bamboo leaf and broad-leaved bamboo leaf,theratio of 1:1 Moso bamboo leaves to broad leaves,and the ratio of 1:3 pure broad leaves to broad leaves respectively.The dynamic changes of litter decomposition were observed for 20 consecutive months in the field forest,using time and different forest,time to interact with different types of litter decomposition,the Moso bamboo litter decomposition in the process of expansion to the broad-leaved forest trends,explore the litter decomposition in the process of C and N release rate,and to reveal the evolution mechanism of litter under broad-leaved forest caused by the expansion of Moso bamboo to broad-leaved forest system.The main research results are as follows:The epansion of Phyllostachys edulis into broad-leaved forest to form bamboo-broad-leaved mixed forest can promote litter decomposition.The decomposition rate of mixed forest is higher than that of pure forest,but the difference between mixe d forest and broad-leaved forest is not obvious.(2)The decomposition rate of litter in 100 meshes was 1:3>broadleaf>bamboo leaf>broadleaf>bamboo leaf>broadleaf>1:1>bamboo leaf>broadleaf>3:1.The decomposition rate in]3 m eshes was:broadleaf>bamboo leaf>broadleaf>1:1>bamboo broadleaf>3:1.and the average decomposition rate of 100 meshes was less than 5.21%of 13 mes hes.The ratio of bamboo to breadth was 3:1,which inhibited litter decomposition,while the other mixed proportion had no significant effect on litter decomposition.(3)There are two stages in litter decomposition.The decomposition rate in the first st age is obviously higher than that in the second stage.(4)The total carbon and nitro gen content of litter decreased during the expansion of Phyllostachys edulis:the N c ontent decreased 26.8%and the total carbon content decreased 17.2%.(5)In the sa me stand,the decomposition rate of the same litter decomposition bag with larger a perture is faster than that with smaller aperture.