Nitrogen deposition alters nitrogen cycling and reduces soil carbon content in low-productivity semiarid Mediterranean ecosystems

Raúl Ochoa-Hueso, Fernando T. Maestre, Asunción De Los Ríos, Sergio Valea, Mark R. Theobald, Marta G. Vivanco, Esteban Manrique, Mathew A. Bowker

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

Anthropogenic N deposition poses a threat to European Mediterranean ecosystems. We combined data from an extant N deposition gradient (4.3-7.3 kg N ha-1 yr-1) from semiarid areas of Spain and a field experiment in central Spain to evaluate N deposition effects on soil fertility, function and cyanobacteria community. Soil organic N did not increase along the extant gradient. Nitrogen fixation decreased along existing and experimental N deposition gradients, a result possibly related to compositional shifts in soil cyanobacteria community. Net ammonification and nitrification (which dominated N-mineralization) were reduced and increased, respectively, by N fertilization, suggesting alterations in the N cycle. Soil organic C content, C:N ratios and the activity of β-glucosidase decreased along the extant gradient in most locations. Our results suggest that semiarid soils in low-productivity sites are unable to store additional N inputs, and that are also unable to mitigate increasing C emissions when experiencing increased N deposition.

Original languageEnglish (US)
Pages (from-to)185-193
Number of pages9
JournalEnvironmental Pollution
Volume179
DOIs
StatePublished - May 22 2013

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Keywords

  • C and N cycling
  • Enzyme activities
  • Extant N gradient
  • Fertilization experiment
  • Soil cyanobacteria community
  • Soil organic C and N content

ASJC Scopus subject areas

  • Toxicology
  • Pollution
  • Health, Toxicology and Mutagenesis

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