Carbon and nitrogen dynamics in early stages of forest litter decomposition as affected by nitrogen addition
The effects of nitrogen (N) availability and tree species on the dynamics of carbon and nitrogen at early stage of decomposition of forest litter were studied in a 13-week laboratory incubation experiment. Fresh litter samples including needle litter (Pinus koraiensis) and two types of broadleaf litters (Quercus mongolica and Tilia amurensis) were collected from a broadleaf-korean pine mixed forest in the northern slope of Changbai Mountain (China). Different doses of N (equal to 0, 30 and 50 kg·ha-1yr-1, respectively, as NH4NO3) were added to litter during the experiment period. The litter decomposition rate expressed as mass loss and respiration rate increased significantly with increasing N availability. The mass loss and cumulative CO2-C emission were higher in leaf litter compared to that in needle litter. The dissolved organic Carbon (DOC) concentrations in litter leachate varied widely between the species, but were not greatly affected by N treatments. Regardless of the N addition rate, both N treatments and species had no significant effect on dissolved organic N (DON) concentrations in litter leachate. About 52·78% of added N was retained in the litter. The percentage of N retention was positively correlated (R2=0.91, p<0.05) with the litter mass loss. This suggested that a forest floor with easily decomposed litter might have higher potential N sink strength than that with more slowly decomposed litter.
作 者： DENG Xiao-wen LIU Ying HAN Shi-jie 作者单位： DENG Xiao-wen(Tianjin Academy of Environmental Sciences, Tianjin 300191, P. R. China;Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China)LIU Ying(College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, P. R. China)
HAN Shi-jie(Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, P. R. China)
刊 名： 林业研究（英文版） 英文刊名： JOURNAL OF FORESTRY RESEARCH 年，卷(期)： 2009 20(2) 分类号： S7 关键词： carbon and nitrogen dynamics decomposition forest litter nitrogen addition