ABSTRACT
We examined nutrient release and ecological stoichiometric characteristics of litters under N deposition in an evergreen broadleaved forest in Mopan Mountain in central Yunnan. Nylon net bag method was used for in situ decomposition of leaf litter and twig litter. There were four treatments, including control (CK, 0 g N·m-2·a-1), low nitrogen (LN, 5 g N·m-2·a-1), medium nitrogen (MN, 15 g N·m-2·a-1), and high nitrogen (HN, 30 g N·m-2·a-1). The results showed that after one year of N addition, the contents of C and N in leaf litter, twig litter and soil increased gradually with the increases of N addition rates, with increases of 0.3%-8.2% and 4.9%-69.0%, respectively. C/N gradually decreased with increasing N addition rates, with a decrease of 0.8%-37.8%. There was no significant difference in P content, C/P and N/P of twig litter under different treatments. Treatment duration and N application rate significantly affected the N and P contents and stoichiometric ratios of leaf litter, twig litter and soil. During the 1-year decomposition process, the residual rates of C, N and P in litters were successively in the modes of release, leaching-enriched-released and leaching-enriched. Exogenous N addition significantly inhibited the release process of C, N and P in litter. The contents of C and P in soil were significantly positively correlated with the contents of N and P in litter, while the contents of N in soil were significantly positively correlated with the contents of C and N in litter. There was a significant correlation of stoichiometric characteristics between litter and soils of evergreen broadleaved forest under N deposition. Our results were helpful to understand the response mechanism of litter decomposition process of forest ecosystem to N deposition.
