Abstract: Nowadays, biological invasions and enhanced nitrogen (N) deposition are two key elements of global change; however, their interactive effects on litter decomposition remain unclear. The present study aims to test whether the interactive effects of these two environmental factors on the litter decomposition and nutrient dynamics are stronger than that of each individual factor. A litterbag method was used to examine the effects of simulated N deposition and burial on mass remaining and the dynamics of N, C, and C/N of leaf litters of invasive plant Flaveria bidentis and cooccurring native Setaria viridis during decomposition. Four treatments were set as following: (1) enhanced N deposition (100% enhancement, 28 kg N·hm^-2·a^-1), (2) burial (in 10 cm depth soil), (3) the combined treatment of the two factors (N deposition enhancement + burial), and (4) the control treatment without N addition and burial. Results showed that the litter decomposition constant (k) of F. bidentis leaf litter under simulated N deposition was significantly decreased compared with the control (1.68 vs. 2.26, respectively), while there was little effect of enhanced N on the decomposition of S. viridis leaf litter. In contrast, burial alone or combined with enhanced N deposition tended to significantly enhance the leaf decomposition of both test species. In particular, while the combination of N deposition and burial significantly enhanced N release from F. bidentis leaf litter, N deposition alone did not affect the N release. Under increasing N deposition, litter management option (soil burial or soil surface) may affect the decomposition rate and nutrient dynamics of invasive species litter.

Key words: Salix matsudana, phytoremediation, removal mechanism, phosphorus concentration