title: Short-term effect of nitrogen addition on nitric oxide emissions from an alpine meadow in the Tibetan Plateau.
abstract: Little information is available on nitric oxide (NO) fluxes from alpine ecosystems. We measured NO fluxes in control and nitrogen (N) addition (NH4NO3, 6 g N m(-2) year(-1)) plots from early June through October 2013 in an alpine meadow on the Tibetan Plateau, China. During the sample period, NO fluxes varied from -0.71 to 3.12 ug m(-2) h(-1) and -0.46 to 7.54 ug m(-2) h(-1) for control and N treatment plots. The mean NO emission in N addition plots (1.68 ug m(-2) h(-1)) was 2.15 times higher than the control plots (0.78 ug m(-2) h(-1)), indicating that alpine meadows may be a source of atmospheric NO, and N additions stimulated NO flux. A positive correlation was found between NO flux and soil temperature, water-filled pore space (WFPS), nitrate (NO3 (-)-N) content but no correlation with soil ammonium (NH4 (+)-N). These results suggest that denitrification is a principal process producing NO flux from alpine meadows.
authors.affiliation: Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, SC, 610041, China. gaoyongheng@gmail.com.|Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO, 80523, USA. gaoyongheng@gmail.com.
authors.forename: Yongheng
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, SC, 610041, China.
authors.forename: Xingxing
authors.initials: X
authors.lastname: Ma
authors.affiliation: Department of Forest and Rangeland Stewardship, Colorado State University, Fort Collins, CO, 80523, USA.
authors.forename: David J
authors.initials: DJ
authors.lastname: Cooper
mesh_terms: D017753:Ecosystem; D065948:Grassland; D009566:Nitrates / Q000737:chemistry; D009569:Nitric Oxide / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis*; D012987:Soil / Q000737:chemistry; D013696:Temperature; D018609:Tibet; D013997:Time Factors; D014867:Water
chemical_list: D009566:Nitrates; D012987:Soil; D014867:Water; D009569:Nitric Oxide; D009584:Nitrogen
keywords: Alpine meadow; Denitrification; NO flux; Nitrogen deposition; Water-filled pore space