title: [Responses of Soil and Plant 15N Natural Abundance to Long-term N Addition in an N-Saturated Pinus massoniana Forest in Southwest China].
abstract: Increasing N deposition in China will possibly cause N saturation of forest ecosystem, further resulting in a series of serious environmental problems. In order to explore the response of forest ecosystem to N deposition in China, and further evaluate and predict the N status of ecosystem, the 15N natural abundance (delta 15N) of soil and plants was measured in a typical Masson pine (Pinus massoniana) forest in southwest China to examine the potential use of delta 15N enrichment factor (epsilon(p/s)) as an effective indicator of N status. Long-term high N addition could significantly increase delta 15N of soil and plants, which was suggested by an on-going N fertilizing experiment with NH4NO3 or NaNO3 for 7 years. Meanwhile, delta 15N of soil and plants under NH, deposition was significantly higher than that under NO- deposition, suggesting different responses of ecosystem to different N-forms of deposition. The "N enrichment factor (epsilon(p/s)) had positive correlations with N deposition, N nitrification, and N leaching in the soil water. Linear correlation between "N enrichment factor and N deposition was found for all Masson pine forests investigated in this and previous studies in China, demonstrating that 15N enrichment factor could be used as an indicator of N status. The NH3 emission control should also be carried out accompanying with NOx emission control in the future, because NH4- deposition had significantly greater impact on the forest ecosystem than NO3- deposition with the same equivalence.
authors.forename: Wen-jing
authors.initials: WJ
authors.lastname: Liu
authors.forename: Rong-hua
authors.initials: RH
authors.lastname: Kang
authors.forename: Ting
authors.initials: T
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Zhu
authors.forename: Lei
authors.initials: L
authors.lastname: Duan
mesh_terms: D002681:China; D065928:Forests; D058465:Nitrification; D009584:Nitrogen / Q000032:analysis*; D009587:Nitrogen Isotopes / Q000032:analysis; D028223:Pinus; D012987:Soil / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D009587:Nitrogen Isotopes; D012987:Soil; D014867:Water; D009584:Nitrogen