title: High nitrogen deposition in an agricultural ecosystem of Shaanxi, China.
abstract: Atmospheric nitrogen (N) deposition plays an important role in the global N cycle. Data for dry and wet N deposition in agricultural ecosystem of Shaanxi in China is still imperfect; in this study, we continuously measured concentrations and fluxes of dry N deposition from 2010 to 2013 in Yangling district of Shaanxi province and wet N deposition from 2010 to 2012. The average annual concentrations of NH3, NO2, HNO3, particulate ammonium, and nitrate (pNH4 (+) and pNO3 (-)) varied among 3.9-9.1, 6.6-8.0, 1.2-1.4, 3.1-4.3, and 3.3-4.8 μg N m(-3), respectively, with mean values of 6.0, 7.2, 1.3, 3.8, and 4.1 μg N m(-3), respectively, during the entire monitoring period. The annual NH4 (+)-N and NO3 (-)-N concentrations in precipitation ranged 3.9-4.3 and 2.8-3.4 mg N L(-1) with the mean values of 4.1 and 3.3 mg N L(-1). The NH4 (+)-N/NO3 (-)-N ratio in rainfall averaged 1.2. Dry N deposition flux was determined to be 19.2 kg N ha(-1) year(-1) and the wet N deposition flux was 27.2 kg N ha(-1) year(-1). The amount of total atmospheric N deposition (dry plus wet) reached 46.4 kg N ha(-1) year(-1), in which dry deposition accounted 41 %. Gaseous N deposition comprised over 75 % of the dry deposition, and the proportion of oxidized N in dry deposition was equal to the reduced N. Therefore, the results suggest that more stringent regional air pollution control policies are required in the target area and that N deposition is an important nutrient resource from the atmosphere that must be taken into consideration in nutrient management planning of agricultural ecosystems.
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Shaanxi, 712100, China.|Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Shaanxi, 712100, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Liang
authors.affiliation: College of Natural Resources and Environment, Northwest A&F University, Shaanxi, 712100, China. tongyanan@nwsuaf.edu.cn.|Key Laboratory of Plant Nutrition and the Agri-environment in Northwest China, Ministry of Agriculture, Shaanxi, 712100, China. tongyanan@nwsuaf.edu.cn.
authors.forename: Yan'an
authors.initials: Y
authors.lastname: Tong
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Xuejun
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Xu
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.|Institute of Plant Nutrition, Resources and Environmental Sciences, Henan Academy of Agricultural Sciences, Zhengzhou, 450002, China.
authors.forename: Xiaosheng
authors.initials: X
authors.lastname: Luo
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Beijing, 100193, China.
authors.forename: Peter
authors.initials: P
authors.lastname: Christie
mesh_terms: D000383:Agriculture; D000393:Air Pollutants / Q000032:analysis*; D064751:Ammonium Compounds / Q000032:analysis; D001272:Atmosphere; D002681:China; D017753:Ecosystem; D004784:Environmental Monitoring; D005740:Gases; D009566:Nitrates / Q000032:analysis; D009584:Nitrogen / Q000032:analysis*; D017672:Nitrogen Compounds / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D064751:Ammonium Compounds; D005740:Gases; D009566:Nitrates; D017672:Nitrogen Compounds; D009584:Nitrogen
keywords: Atmospheric pollution; Dry deposition; Reactive N; Seasonal variation; Wet deposition