The decomposition processes and return of carbon, nitrogen, and phosphorus of Phragmites australis litter with different detritus amount

Litter decomposition is essential for carbon and nutrient cycling in wetland ecosystems. The management of Phragmites australis, a kind of widespread wetland emergent plant, is generally of great importance to the regulation of this biogeochemical cycle. In this study, we conducted a 210 days mesocosm experiment to examine the decomposition processes and return of elements carbon, nitrogen, and phosphorus in Phragmites litter under the influence of different detritus amount. Our results verified that in the range of 0-1,000 g/m(2) of detritus amount of Phragmites litter, the decomposition of biomass, lignin, and cellulose of Phragmites litter was better correlated with the stoichiometric ratios in ambient water than in Phragmites litter itself. The detritus amount did not affect the decomposition of biomass, lignin, cellulose, or release of total phosphorous (TP) in Phragmites litter, but did affect the total organic carbon (TOC) and total nitrogen (TN). The overall decomposition rate and decomposition rates of lignin and cellulose of Phragmites in water varied between 0.001 and 0.004 per day. Therefore, the detritus amount of Phragmites litter after the typical harvesting method might affect the decomposition of Phragmites litter more by influencing water. This has a certain reference value to further research on wetland ecosystem management.