title: Soil [N] modulates soil C cycling in CO2-fumigated tree stands: a meta-analysis.
abstract: Under elevated atmospheric CO(2) concentrations, soil carbon (C) inputs are typically enhanced, suggesting larger soil C sequestration potential. However, soil C losses also increase and progressive nitrogen (N) limitation to plant growth may reduce the CO(2) effect on soil C inputs with time. We compiled a data set from 131 manipulation experiments, and used meta-analysis to test the hypotheses that: (1) elevated atmospheric CO(2) stimulates soil C inputs more than C losses, resulting in increasing soil C stocks; and (2) that these responses are modulated by N. Our results confirm that elevated CO(2) induces a C allocation shift towards below-ground biomass compartments. However, the increased soil C inputs were offset by increased heterotrophic respiration (Rh), such that soil C content was not affected by elevated CO(2). Soil N concentration strongly interacted with CO(2) fumigation: the effect of elevated CO(2) on fine root biomass and -production and on microbial activity increased with increasing soil N concentration, while the effect on soil C content decreased with increasing soil N concentration. These results suggest that both plant growth and microbial activity responses to elevated CO(2) are modulated by N availability, and that it is essential to account for soil N concentration in C cycling analyses.
authors.affiliation: Department of Biology, University of Antwerp (UA), Wilrijk, Belgium. wouter.dieleman@ua.ac.be
authors.forename: W I J
authors.initials: WI
authors.lastname: Dieleman
authors.forename: S
authors.initials: S
authors.lastname: Luyssaert
authors.forename: A
authors.initials: A
authors.lastname: Rey
authors.forename: P
authors.initials: P
authors.lastname: de Angelis
authors.forename: C V M
authors.initials: CV
authors.lastname: Barton
authors.forename: M S J
authors.initials: MS
authors.lastname: Broadmeadow
authors.forename: S B
authors.initials: SB
authors.lastname: Broadmeadow
authors.forename: K S
authors.initials: KS
authors.lastname: Chigwerewe
authors.forename: M
authors.initials: M
authors.lastname: Crookshanks
authors.forename: E
authors.initials: E
authors.lastname: Dufrêne
authors.forename: P G
authors.initials: PG
authors.lastname: Jarvis
authors.forename: A
authors.initials: A
authors.lastname: Kasurinen
authors.forename: S
authors.initials: S
authors.lastname: Kellomäki
authors.forename: V
authors.initials: V
authors.lastname: Le Dantec
authors.forename: M
authors.initials: M
authors.lastname: Liberloo
authors.forename: M
authors.initials: M
authors.lastname: Marek
authors.forename: B
authors.initials: B
authors.lastname: Medlyn
authors.forename: R
authors.initials: R
authors.lastname: Pokorný
authors.forename: G
authors.initials: G
authors.lastname: Scarascia-Mugnozza
authors.forename: V M
authors.initials: VM
authors.lastname: Temperton
authors.forename: D
authors.initials: D
authors.lastname: Tingey
authors.forename: O
authors.initials: O
authors.lastname: Urban
authors.forename: R
authors.initials: R
authors.lastname: Ceulemans
authors.forename: I A
authors.initials: IA
authors.lastname: Janssens
mesh_terms: D001272:Atmosphere; D018533:Biomass; D057486:Carbon Cycle; D002245:Carbon Dioxide; D005308:Fertilizers; D058458:Nitrogen Cycle; D012987:Soil / Q000032:analysis*; D014197:Trees / Q000254:growth & development*
chemical_list: D005308:Fertilizers; D012987:Soil; D002245:Carbon Dioxide