title: Different fates of deposited NH4+ and NO3- in a temperate forest in northeast China: a15N tracer study.
abstract: Increasing atmospheric reactive nitrogen (N) deposition due to human activities could change N cycling in terrestrial ecosystems. However, the differences between the fates of deposited NH4+ and NO3- are still not fully understood. Here, we investigated the fates of deposited NH4+ and NO3-, respectively, via the application of15NH4NO3and NH415NO3in a temperate forest ecosystem. Results showed that at 410 days after tracer application, most 15NH4+ was immobilized in litter layer (50 ± 2%), while a considerable amount of 15NO3- penetrated into 0-5 cm mineral soil (42 ± 2%), indicating that litter layer and 0-5 cm mineral soil were the major N sinks of NH4+ and NO3-, respectively. Broad-leaved trees assimilated more15N under NH415NO3treatment compared to under15NH4NO3treatment, indicating their preference for NO3--N. At 410 days after tracer application, 16 ± 4% added15N was found in aboveground biomass under 15NO3- treatment, which was twice more than that under 15NH4+ treatment (6 ± 1%). At the same time, approximately 80% added15N was recovered in soil and plants under both treatments, which suggested that this forest had high potential for retention of deposited N. These results provided evidence that there were great differences between the fates of deposited NH4+ and NO3-, which could help us better understand the mechanisms and capability of forest ecosystems as a sink of reactive nitrogen.
authors.affiliation: CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang, 110016, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.affiliation: CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang, 110016, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Peng
authors.affiliation: CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang, 110016, China.
authors.forename: Zongwei
authors.initials: Z
authors.lastname: Xia
authors.affiliation: CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang, 110016, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Jianfei
authors.initials: J
authors.lastname: Sun
authors.affiliation: CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang, 110016, China.|University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Decai
authors.initials: D
authors.lastname: Gao
authors.affiliation: CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang, 110016, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Dai
authors.affiliation: CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang, 110016, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Jiang
authors.affiliation: CAS Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Shenyang, 110016, China.
authors.forename: Edith
authors.initials: E
authors.lastname: Bai
mesh_terms: D002681:China; D017753:Ecosystem; D065928:Forests; D009584:Nitrogen; D058458:Nitrogen Cycle; D012987:Soil / Q000737:chemistry*; D014197:Trees
chemical_list: D012987:Soil; D009584:Nitrogen
keywords: broad-leaved and Korean pine (Pinus koraiensis) mixed forest; nitrogen deposition; nitrogen fate; nitrogen retention; nitrogen saturation