| Plant-litter-Soil is an important part of ecosystem. Among them, the plant play a crucial role. They absorp various nutrients from the soil and grow, and the part of the death of the organ fall to the surface, which nutrient returned to the soil. Therefore, the study of litter has been one of the important research content of the forest ecosystem functions. In this study, we set up169litter collection boxes, litter production, litter nutrient dynamics, nutrient return and effect of ice storm on them were studied in a subtropical evergreen borad-leaved forest at a24-ha forest dynamics in Gutianshan National Naturnal Reserve, China. The objective of study is to understand litter quantity, the content and return dynamics of carbon, nitrogen and phosphorus in leaf litter of Castanopsis eyrei and Schima superba, and snow disaster on its influence, which would be helpful for providing theoretical basic data to recover and reconstruct the forest after the ice storm.The result from the study are shown below:1.Litterfall productionThe litterfall production in2007,2008and2009respectively was5.14t·ha-1·a-1,2.61t-ha-1·a-1,3.83t·ha-1·a-1. The result showed forest had obvious total litter rhthmand seasonal dynamic was bimodal. Leaf litter accounted for an absolute advantage,83.07%of the total litter production, followed by twig litter、bark litter and miscellanea litter. Monthly changes in leaf litter amout was very similar to the trend of the total litterfall, and both were significant, while twig, bark and miscellanea litter content and total litter was not significant correlation. C. eyrei showed obvious bimodal, the first peak was in April, and the second peak was in November, and S. superba the obvious peak was in November, a small peak in April and May. By January to February2008snow storms, the litterfall production of C. eyrei and S. superba reduced generally, and the peak impact more serious.2. Leaf litter carbon, nitrogen and phosphorus content and the effect of snow stormsThe content of C, N, P in C. eyrei were39.51-48.11%,0.838-1.903%, and0.202-1.977g·kg-1, averge were46.09%,1.213%and0.650g·kg-1; while the content of C, N, P in S. superba were45.02-51.86%,0.593-1.460%, and0.125-1.538g-kg-1, averge were49.31%,1.066%and0.625g-kg-1. The t-test analysis, the carbon content was relatively stable in C. eyrei and S. superb litter leaves, and there was no significant difference(P>0.05).In August the nitrongen content was highest, and after snow the highest was January in C. eyrei litter leaves. In addition to spring(3-5) the content was lower than before the snow, the other mouths were higher than before snow storms. Compared before and after snow, the nitrongen content in S. superb litter leaves, in March and after snow April were highest. Among, in March, July, August and November the nitrongen content was higher than after snow storms, and other mouths were opposite. The t-test results, which was no significant difference in May, June, August-October(P>0.05), the other mouths the difference were significant (P<0.001). The nitrogen content in S. superb in January, March, April, September, November and December were a very significant difference (P<0.01), significant difference (P<0.05) in October and other months the difference was not significant (P>0.05).The phosphorus content of C. eyrei litter leaves were higher than before snow storms, the t-test result, compared before and after snow were very significant(P<0.01), while S. superb was different, besides March and April, the phosphorus content were higher than before snow storms, and from May through September the tendency was evident. In February it reached to the edge of a significant level, the other months reached to a very significant difference (P<0.01).3. The return of carbon, nitrogen and phosphorus in leaf litterThe carbon annual return of C. eyrei and S. superb litter leaves reached to823.106kg·ha·a-1, followed by nitrogen, the return of19.196kg·ha·a-1, at least for phosphorus, the return was0.939kg·ha·a-1. Nutrient return in litter was determined by the nutrient content and litter production. The carbon, nitrogen, phosphorus return of C. eyrei litter leaves in April was the highest,nevertheless,in S.superb litter leaves was highest in November. |
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