Chin J Plant Ecol ›› 2020, Vol. 44 ›› Issue (3): 214-227.DOI: 10.17521/cjpe.2019.0299

• Research Articles • Previous Articles     Next Articles

Response of leaf litter decomposition of different tree species to nitrogen addition in a subtropical forest

CHEN Si-Lu1,2,CAI Jin-Song4,LIN Cheng-Fang1,2,3,*(),SONG Hao-Wei1,2,YANG Yu-Sheng1,2,3   

  1. 1School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China
    2State Key Laboratory of Humid Subtropical Mountain Ecology, Fuzhou, 350007, China
    3Sanming Research Station of Forest Ecosystem and Global Change, Sanming, Fujian 365000, China
    4State-owned Forest Farm in the Suburbs of Sanming, Fujian Province, Sanming, Fujian 365000, China
  • Received:2019-11-04 Accepted:2020-02-06 Online:2020-03-20 Published:2020-04-30
  • Contact: Cheng-Fang LIN
  • Supported by:
    National Natural Science Foundation of China(31770663);Natural Science Foundation of Fujian(2018J01718)


Aims Litter decomposition plays a vital role in nutrient recycling of forest ecosystems. The decomposition rate of leaves can vary among tree species with different substrate quality and environmental conditions, such as the supply of exogenous nitrogen (N). However, the effects of exogenous N on leaf litter decomposition of different tree species in subtropical forests with high nitrogen deposition background remain poorly understood. Thus this study was designed to address the effect of N addition on litter decomposition of different tree species in a subtropical forest ecosystem.
Methods Leaf litters of four common tree species with contrasting substrate quality were collected and decomposed in fertilized (50 kg N·hm -2·a -1) and control (0 kg N·hm -2·a -1) plots for up to two years by using the nylon bag method, in Sanming Castanopsis kawakamii nature reserve of Fujian Province.
Important findings The litter decomposition rate in control plots ranked as follows: Michelia odora (0.557 a -1), Castanopsis carlesii (0.440 a -1), Acacia confusa (0.357 a -1), Cunninghamia lanceolata (0.354 a -1), while the decomposition rate in N addition plots ranked as follows: Michelia odora (0.447 a -1), Castanopsis carlesii (0.354 a -1), Cunninghamia lanceolata (0.291 a -1), Acacia confusa (0.230 a -1). Overall, N addition significantly increased the litter mass remaining of Michelia odora, Acacia confusa and Castanopsis carlesii, but not Cunninghamia lanceolata. N addition not only slowed down the release of N, but also retarded the degradation of lignin and cellulose in the decomposition process. Moreover, N addition increased the activities of β-glucosidase (βG) and acid phosphatase, had species-specific effects on the activity of cellulose hydrolase, and decreased the activity of β-N-acetylglucosaminidase and phenoloxidase (PHO). The litter mass loss rate was positively correlated with the activities of carbon acquiring enzyme (βG) in litter layer and the extractives, negatively correlated with carbon concentration, cellulose and lignin, but did not correlate significantly with the initial N concentration. Further analysis found an interactive effect of litter type and N addition on the degradation of cellulose and lignin, but not on dry mass loss. Overall, our results demonstrated that litter chemical components may be better parameters to predict the decomposition rate of leaf litters than the initial nutrient concentrations, and N addition could decrease leaf litter decomposition by inhibiting oxidase (e.g. PHO). We call for further experiments to involve more species and longer time for revealing the response of leaf litter decomposition and its extracellular enzyme activity to N addition.

Key words: leaf litter decomposition, nitrogen deposition, enzyme activities, subtropical forest