Soil carbon sequestration in prairie grasslands increased by chronic nitrogen addition

Dario A. Fornara, David Tilman, B. Z. Houlton

Research output: Contribution to journalArticlepeer-review

173 Scopus citations

Abstract

Human-induced increases in nitrogen (N) deposition are common across many terrestrial ecosystems worldwide. Greater N availability not only reduces biological diversity, but also affects the biogeochemical coupling of carbon (C) and N cycles in soil ecosystems. Soils are the largest active terrestrial C pool and N deposition effects on soil C sequestration or release could have global importance. Here, we show that 27 years of chronic N additions to prairie grasslands increased C sequestration in mineral soils and that a potential mechanism responsible for this C accrual was an N-induced increase in root mass. Greater soil C sequestration followed a dramatic shift in plant community composition from native-speciesrich C4 grasslands to naturalized-species-rich C3 grasslands, which, despite lower soil C gains per unit of N added, still acted as soil C sinks. Since both high plant diversity and elevated N deposition may increase soil C sequestration, but N deposition also decreases plant diversity, more research is needed to address the long-term implications for soil C storage of these two factors. Finally, because exotic C3 grasses often come to dominate N-enriched grasslands, it is important to determine if such N-dependent soil C sequestration occurs across C3 grasslands in other regions worldwide.

Original languageEnglish (US)
Pages (from-to)2030-2036
Number of pages7
JournalEcology
Volume93
Issue number9
DOIs
StatePublished - Sep 2012

Keywords

  • Biodiversity
  • Ecosystem functioning
  • Ecosystem services
  • Fire
  • Nitrogen deposition
  • Root mass
  • Soil carbon sequestration

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