title: Nitrogen distribution and cycling through water flows in a subtropical bamboo forest under high level of atmospheric deposition.
abstract: BACKGROUND
  The hydrological cycle is an important way of transportation and reallocation of reactive nitrogen (N) in forest ecosystems. However, under a high level of atmospheric N deposition, the N distribution and cycling through water flows in forest ecosystems especially in bamboo ecosystems are not well understood.
  
  
  RESULTS
  In order to investigate N fluxes through water flows in a Pleioblastus amarus bamboo forest, event rainfall/snowfall (precipitation, PP), throughfall (TF), stemflow (SF), surface runoff (SR), forest floor leachate (FFL), soil water at the depth of 40 cm (SW1) and 100 cm (SW2) were collected and measured through the whole year of 2009. Nitrogen distribution in different pools in this ecosystem was also measured. Mean N pools in vegetation and soil (0-1 m) were 351.7 and 7752.8 kg ha(-1). Open field nitrogen deposition at the study site was 113.8 kg N ha(-1) yr(-1), which was one of the highest in the world. N-NH4(+), N-NO3(-) and dissolved organic N (DON) accounted for 54%, 22% and 24% of total wet N deposition. Net canopy accumulated of N occurred with N-NO3(-) and DON but not N-NH4(+). The flux of total dissolved N (TDN) to the forest floor was greater than that in open field precipitation by 17.7 kg N ha(-1) yr(-1), due to capture of dry and cloudwater deposition net of canopy uptake. There were significant negative exponential relationships between monthly water flow depths and monthly mean TDN concentrations in PP, TF, SR, FFL and SW1.
  
  
  CONCLUSIONS
  The open field nitrogen deposition through precipitation is very high over the world, which is the main way of reactive N input in this bamboo ecosystem. The water exchange and N consume mainly occurred in the litter floor layer and topsoil layer, where most of fine roots of bamboo distributed.
authors.affiliation: College of Forestry, Sichuan Agricultural University, Ya'an, Sichuan, China.
authors.forename: Li-hua
authors.initials: LH
authors.lastname: Tu
authors.forename: Ting-xing
authors.initials: TX
authors.lastname: Hu
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Li-hua
authors.initials: LH
authors.lastname: Huang
authors.forename: Yin-long
authors.initials: YL
authors.lastname: Xiao
authors.forename: Gang
authors.initials: G
authors.lastname: Chen
authors.forename: Hong-ling
authors.initials: HL
authors.lastname: Hu
authors.forename: Li
authors.initials: L
authors.lastname: Liu
authors.forename: Jiang-kun
authors.initials: JK
authors.lastname: Zheng
authors.forename: Zhen-Feng
authors.initials: ZF
authors.lastname: Xu
authors.forename: Liang-hua
authors.initials: LH
authors.lastname: Chen
mesh_terms: D002681:China; D017753:Ecosystem; D004784:Environmental Monitoring; D009584:Nitrogen / Q000737:chemistry* / Q000378:metabolism; D058458:Nitrogen Cycle; D018515:Plant Leaves / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism*; D011891:Rain; D031787:Sasa / Q000378:metabolism*; D012621:Seasons; D012987:Soil / Q000737:chemistry*; D014197:Trees / Q000502:physiology; D014329:Tropical Climate; D014867:Water
chemical_list: D012987:Soil; D014867:Water; D009584:Nitrogen