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The response of soil CO 2 flux to changes in atmospheric CO 2 , nitrogen supply and plant diversity
Author(s) -
Craine Joseph M.,
Wedin David A.,
Reich Peter B.
Publication year - 2001
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1046/j.1354-1013.2001.00455.x
Subject(s) - environmental science , soil water , flux (metallurgy) , carbon dioxide , ecosystem , soil carbon , nitrogen , environmental chemistry , agronomy , chemistry , soil science , ecology , biology , organic chemistry
We measured soil CO 2 flux over 19 sampling periods that spanned two growing seasons in a grassland Free Air Carbon dioxide Enrichment (FACE) experiment that factorially manipulated three major anthropogenic global changes: atmospheric carbon dioxide (CO 2 ) concentration, nitrogen (N) supply, and plant species richness. On average, over two growing seasons, elevated atmospheric CO 2 and N fertilization increased soil CO 2 flux by 0.57 µmol m −2 s −1 (13% increase) and 0.37 µmol m −2 s −1 (8% increase) above average control soil CO 2 flux, respectively. Decreases in planted diversity from 16 to 9, 4 and 1 species decreased soil CO 2 flux by 0.23, 0.41 and 1.09 µmol m −2 s −1 (5%, 8% and 21% decreases), respectively. There were no statistically significant pairwise interactions among the three treatments. During 19 sampling periods that spanned two growing seasons, elevated atmospheric CO 2 increased soil CO 2 flux most when soil moisture was low and soils were warm. Effects on soil CO 2 flux due to fertilization with N and decreases in diversity were greatest at the times of the year when soils were warm, although there were no significant correlations between these effects and soil moisture. Of the treatments, only the N and diversity treatments were correlated over time; neither were correlated with the CO 2 effect. Models of soil CO 2 flux will need to incorporate ecosystem CO 2 and N availability, as well as ecosystem plant diversity, and incorporate different environmental factors when determining the magnitude of the CO 2 , N and diversity effects on soil CO 2 flux.