title: Warming and nitrogen addition increase litter decomposition in a temperate meadow ecosystem.
abstract: BACKGROUND
  Litter decomposition greatly influences soil structure, nutrient content and carbon sequestration, but how litter decomposition is affected by climate change is still not well understood.
  
  
  RESULTS
  A field experiment with increased temperature and nitrogen (N) addition was established in April 2007 to examine the effects of experimental warming, N addition and their interaction on litter decomposition in a temperate meadow steppe in northeastern China. Warming, N addition and warming plus N addition reduced the residual mass of L. chinensis litter by 3.78%, 7.51% and 4.53%, respectively, in 2008 and 2009, and by 4.73%, 24.08% and 16.1%, respectively, in 2010. Warming, N addition and warming plus N addition had no effect on the decomposition of P. communis litter in 2008 or 2009, but reduced the residual litter mass by 5.58%, 15.53% and 5.17%, respectively, in 2010. Warming and N addition reduced the cellulose percentage of L. chinensis and P. communis, specifically in 2010. The lignin percentage of L. chinensis and P. communis was reduced by warming but increased by N addition. The C, N and P contents of L. chinensis and P. communis litter increased with time. Warming and N addition reduced the C content and C:N ratios of L. chinensis and P. communis litter, but increased the N and P contents. Significant interactive effects of warming and N addition on litter decomposition were observed (P<0.01).
  
  
  CONCLUSIONS
  The litter decomposition rate was highly correlated with soil temperature, soil water content and litter quality. Warming and N addition significantly impacted the litter decomposition rate in the Songnen meadow ecosystem, and the effects of warming and N addition on litter decomposition were also influenced by the quality of litter. These results highlight how climate change could alter grassland ecosystem carbon, nitrogen and phosphorus contents in soil by influencing litter decomposition.
authors.affiliation: Institute of Grassland Sciences, Northeast Normal University, Key Laboratory for Vegetation Ecology, Ministry of Education, Changchun 130024, China.
authors.forename: Shiwei
authors.initials: S
authors.lastname: Gong
authors.affiliation: Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Key Laboratory of Dryland Agriculture, Ministry of Agriculture, Beijing 100081, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Guo
authors.affiliation: Institute of Grassland Sciences, Northeast Normal University, Key Laboratory for Vegetation Ecology, Ministry of Education, Changchun 130024, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Institute of Grassland Sciences, Northeast Normal University, Key Laboratory for Vegetation Ecology, Ministry of Education, Changchun 130024, China.
authors.forename: Jixun
authors.initials: J
authors.lastname: Guo
mesh_terms: D017753:Ecosystem; D057232:Global Warming; D009584:Nitrogen / Q000737:chemistry*; D012987:Soil / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000032:analysis
chemical_list: D012987:Soil; D014867:Water; D009584:Nitrogen