Dynamic of leaf litter stoichiometric traits dynamic and its relations with decomposition rates under three forest types in Three Gorges Reservoir Area

Abstract

Litter decomposition is an important link between bioelement cycles and energy flow in the forest ecosystems, and the main source of nutrients for plants and soil. The relationships were studied between leaf litter stoichiometric traits dynamic and decomposition rate under different forest types using litter bag method in this paper to quantify the effects of stoichiometric traits dynamic on leaf litter decomposition and to get a better understanding to the biochemistry of litter-soil continuum. The results were showed as follows: the sequence of litter decomposition rate for the three forest types was Pinus massoniana stand (PM) <0.01), negatively with C concentration (P<0.01), C/ N ratio (P<0.01), and negative quadratic function with N/ P ratio (P< 0.01). P concentration was different in three stands, and negatively linearly related to the decomposition rate for QV (P< 0.01) and PM (P <0.05), and negative quadratic related for PQ (P <0.05). The decomposition rate and leaf litter stoichiometry was different among the three stands. The dynamic of C, C/ N ratio and N/ P ratio in the three stands were similar showing a significant positive correlation with N concentration. The possible reason for this may be that the plants in high latitudes are more susceptible to N restrictions, while those in low latitudes are more susceptible to P restrictions. Whether the plant is limited by N or P, the stoichiometry for different plants is influenced by different environmental factors. This study indicated that the nutrient dynamic during the decomposition of litter leaf under different forest types tend to help itself decompose. The concentration dynamic for N and P was the major factors in regulating carbon balance of ecosystem and litter decomposition, nutrient transfer in mixed litter is the reason for decomposition acceleration.