title: Effects of vegetation type on microbial biomass carbon and nitrogen in subalpine mountain forest soils.
abstract: OBJECTIVE
  Microbial biomass plays an important role in nutrient transformation and conservation of forest and grassland ecosystems. The objective of this study was to determine the microbial biomass among three vegetation types in subalpine mountain forest soils of Taiwan.
  
  
  METHODS
  Tatachia is a typical high-altitude subalpine temperate forest ecosystem in Taiwan with an elevation of 1800-3952 m and consists of three vegetation types: spruce, hemlock, and grassland. Three plots were selected in each vegetation type. Soil samples were collected from the organic layer, topsoil, and subsoil. Microbial biomass carbon (Cmic) was determined by the chloroform fumigation-extraction method, and microbial biomass nitrogen (Nmic) was determined from the total nitrogen (Ntot) released during fumigation-extraction. Bacteria, actinomycetes, fungi, cellulolytic microbes, phosphate-solubilizing microbes, and nitrogen-fixing microbes were also counted.
  
  
  RESULTS
  The Cmic and Nmic were highest in the surface soil and declined with the soil depth. These were also highest in spruce soils, followed by in hemlock soils, and were lowest in grassland soils. Cmic and Nmic had the highest values in the spring season and the lowest values in the winter season. Cmic and Nmic had significantly positive correlations with total organic carbon (Corg) and Ntot. Contributions of Cmic and Nmic, respectively, to Corg and Ntot indicated that the microbial biomass was immobilized more in spruce and hemlock soils than in grassland soils. Microbial populations of the tested vegetation types decreased with increasing soil depth.
  
  
  CONCLUSIONS
  Cmic and Nmic were high in the organic layer and decreased with the depth of layers. These values were higher for spruce and hemlock soils than for grassland soils. Positive correlations were observed between Cmic and Nmic and between Corg and Ntot.
authors.affiliation: Department of Food Science, China University of Science and Technology, Nankang, Taipei, Taiwan; Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan.
authors.forename: Anita
authors.initials: A
authors.lastname: Ravindran
authors.affiliation: Department of Food Science, China University of Science and Technology, Nankang, Taipei, Taiwan; Department of Biochemical Science and Technology, National Taiwan University, Taipei, Taiwan. Electronic address: ssyang@ntu.edu.tw.
authors.forename: Shang-Shyng
authors.initials: SS
authors.lastname: Yang
mesh_terms: D018533:Biomass; D002244:Carbon / Q000032:analysis*; D015169:Colony Count, Microbial; D065928:Forests; D009584:Nitrogen / Q000032:analysis*; D012988:Soil Microbiology; D013624:Taiwan
chemical_list: D002244:Carbon; D009584:Nitrogen
keywords: Forest vegetation; Microbial biomass carbon and nitrogen; Microbial populations