Plant species mediate changes in soil microbial N in response to elevated CO2

Bruce A. Hungate, Josep Canadell, F. Stuart Chapin

Research output: Contribution to journalArticle

84 Scopus citations

Abstract

The effect of elevated CO2 on plant-microbial interactions and nitrogen (N) cycling is critical to predicting plant growth responses to elevated CO2, because plant growth is often N-limited. We investigated whether the effects of elevated CO2 on plant-microbial N dynamics differed among six annual plant species: three European grasses that have invaded California grasslands, and one grass and two forbs native to California serpentine grassland. Elevated CO2 altered plant N pools and 15NH4+ uptake, but the direction and magnitude of the changes were species dependent. The introduced grasses showed increased plant N pools and 15NH4+ uptake, whereas the native species showed smaller increases or even decreases in plant N pools and 15NH4+ uptake. Under nutrient enrichment, soil microbial N and 15NH4+ uptake differed among soils with different plant species, but they were not affected by elevated CO2. At low nutrients, elevated CO2 altered soil microbial N and 15NH4+ uptake, but the direction and magnitude of the changes were species dependent. The changes in soil microbial N were positively correlated with changes in the plant N pool, suggesting that there was no trade-off in N uptake between plants and microbes. These results also suggest that plant species composition will partly determine the direction of changes in soil N cycling in response to elevated CO2.

Original languageEnglish (US)
Pages (from-to)2505-2515
Number of pages11
JournalEcology
Volume77
Issue number8
DOIs
StatePublished - Jan 1 1996

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Keywords

  • Annual grassland
  • Elevated CO
  • Functional groups
  • Introduced vs. Native species
  • Jasper ridge, california
  • N
  • Nitrogen cycle
  • Nitrogen immobilization, uptake, and partitioning
  • Plantmicrobe N interactions

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics

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