Litterfall interception by understorey vegetation delayed litter decomposition in Cinnamomum camphora plantation forest

This study was carried out to improve our understanding of the interception effect of understorey vegetation on litter decomposition in Cinnamomum camphora plantation forest of subtropical China. The interception simulation experiment in field was performed to determine how the litterfall interception delayed the leaf litter decomposition of C. camphora, by comparing the difference in variables among 4 litter interception locations. The results showed that total mass loss, lignin loss, cellulose loss, microbial activities (CO2 release, fungal biomass and enzyme activities), and water content except nitrogen for litters on the crown were significantly lower than that of litters without interception. The maximum mass loss difference value among litter locations reached 35 %, indicative of obvious decomposition delay by the understorey. Litter CO2 release, enzyme activities and water content exhibited a clear seasonal pattern, suggesting a strong relation between the degree of microbial activities and the succession of cold and warm as well as moist and dry periods. A clear nitrogen increase was observed in this experiment, indicating persistent immobilization. No clear variation pattern in nitrogen content was observed in this study, which was probably mixed by the N precipitation from acid rain. The litterfall interception delayed the decomposition of leaf litter, displaying slow decomposition rate and inhibitive microbial activities by interception, which presumably resulted from low water content on the crown.