Nitrogen-15 signals of leaf-litter-soil continuum as a possible indicator of ecosystem nitrogen saturation by forest succession and N loads

Huajun Fang, Guirui Yu, Shulan Cheng, Tianhong Zhu, Jiaojiao Zheng, Jiangming Mo, Junhua Yan, Yiqi Luo

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

Abstract

Understanding forest carbon cycling responses to atmospheric N deposition is critical to evaluating ecosystem N dynamics. The natural abundance of 15N (δ15N) has been suggested as an efficient and non-invasive tool to monitor N pools and fluxes. In this study, three successional forests in southern China were treated with four levels of N addition. In each treatment, we measured rates of soil N mineralization, nitrification, N2O emission and inorganic N leaching as well as N concentration and δ15N of leaves, litters and soils. We found that foliar N concentration and δ15N were higher in the mature broadleaf forest than in the successional pine or mixed forests. Three-year continuous N addition did not change foliar N concentration, but significantly increased foliar δ15N (p < 0.05). Also, N addition decreased the δ15N of top soil in the N-poor pine and mixed forests and significantly increased that of organic and mineral soils in N-rich broadleaf forests (p < 0.05). In addition, the soil N2O emission flux and inorganic N leaching rate increased with increasing N addition and were positively correlated with the 15N enrichment factor (εp/s) of forest ecosystems. Our study indicates that δ15N of leaf, litter and soil integrates various information on plant species, forest stand age, exogenous N input and soil N transformation and loss, which can be used to monitor N availability and N dynamics in forest ecosystems caused by increasing N deposition in the future.

Original languageEnglish (US)
Pages (from-to)251-263
Number of pages13
JournalBiogeochemistry
Volume102
Issue number1
DOIs
StatePublished - 2011
Externally publishedYes

Keywords

  • N natural abundance successional stages
  • N addition
  • N loss
  • N transformation
  • Subtropical China

ASJC Scopus subject areas

  • Environmental Chemistry
  • Water Science and Technology
  • Earth-Surface Processes

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