Objective To explore the potential mechanisms of interaction and function between bamboo forest and its understory vegetation's leaf litter, and provide a theoretical reference for the rational management of understory vegetation in Phyllostachys edulis forest.

Method The litter in situ decomposition and nutrient release process of Ph. edulis and understory vegetation (Dicranopteris pedata) in Changning of Sichuan Province were investigated using litter bag.

Result (1) The initial C, N, P contents and Carbonyl C of D. pedata were higher than those of Ph. edulis (P < 0.05), while C:N, C:P and Alkyl C, O-alkyl C and Aromatic C of D. pedata were all lower than those of P. edulis (P < 0.05). (2) The rate of litter decomposition and nutrient releasing of D. pedata were higher than that of Ph. edulis. The decomposition coefficient of Ph. edulis and D. pedata were 0.58±0.03 and 0.73±0.02, respectively. C, N and P nutrient release all showed net release. (3) The litter mixture of Ph. edulis and D. pedata had no significant effect on the decomposition rate, however, it significantly inhibited the release of N and P elements throughout the decomposition cycle and C elements in the late. (4) The change pattern of element content in litter decomposition process of Ph. edulis and D. pedata showed that C content and C:N ratio turned out a downward trend, and N content and N:P ratio increased slightly. P content showed a slight downward trend, and C:P ratio fluctuated. (5) Litter decomposition rate was positively correlated with soil temperature, initial litter N and P content (P < 0.01), and negatively correlated with C:N and C:P of initial litter (P < 0.01), but had no significant correlation with soil water content.

Conclusion There was no significant mixed effect of decomposition rate, but the mixed effect of nutrient release showed certain negative effects and different periodic features.