Nitrogen regulation of the climate-carbon feedback: Evidence from a long-term global change experiment

Shuli Niu, Rebecca A. Sherry, Xuhui Zhou, Shiqiang Wan, Yiqi Luo

Research output: Contribution to journalArticlepeer-review

53 Scopus citations

Abstract

Modeling studies have shown that nitrogen (N) strongly regulates ecosystem responses and feedback to climate warming. However, it remains unclear what mechanisms underlie N regulation of ecosystem-climate interactions. To examine N regulation of ecosystem feedback to climate change, we have conducted a warming and clipping experiment since November 1999 in a tallgrass prairie of the Great Plains, USA. Infrared heaters were used to elevate soil temperature by an average of 1.968°C at a depth of 2.5 cm from 2000 to 2008. Yearly biomass clipping mimicked hay or biofuel feedstock harvest. We measured carbon (C) and N concentrations, estimated their content and C:N ratio in plant, root, litter, and soil pools. Warming significantly stimulated C storage in aboveground plant, root, and litter pools by 17%, 38%, and 29%, respectively, averaged over the nine years (all P < 0.05) but did not change soil C content or N content in any pool. Plant C:N ratio and nitrogen use efficiency increased in the warmed plots compared to the control plots, resulting primarily from increased dominance of C4 plants in the community. Clipping significantly decreased C and N storage in plant and litter pools (all P < 0.05) but did not have interactive effects with warming on either C or N pools over the nine years. Our results suggest that increased ecosystem nitrogen use efficiency via a shift in species composition toward C4 dominance rather than plant N uptake is a key mechanism underlying warming stimulation of plant biomass growth.

Original languageEnglish (US)
Pages (from-to)3261-3273
Number of pages13
JournalEcology
Volume91
Issue number11
DOIs
StatePublished - Nov 2010
Externally publishedYes

Keywords

  • Biofuel harvest
  • C:N ratio
  • Carbon storage
  • Climate change
  • Land use change
  • Nitrogen use efficiency
  • Soil carbon
  • Warming

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

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