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Afforestation alters the composition of functional genes in soil and biogeochemical processes in South American grasslands

Authors: 
Berthrong ST, CW Schadt, G PiƱeiro, RB Jackson
Year: 
2009
Journal: 
Applied and Environmental Microbiology
Journal Volume/Pages: 
75:6240-6248

Soil microbes are highly diverse and control most soil biogeochemical reactions. We examined how microbial functional genes and biogeochemical pools responded to the altered chemical inputs accompanying land use change. We examined paired native grasslands and adjacent Eucalyptus plantations (previously grassland) in Uruguay, a region that lacked forests before European settlement. Along with measurements of soil carbon, nitrogen, and bacterial diversity, we analyzed functional genes using the GeoChip 2.0 microarray, which simultaneously quantified several thousand genes involved in soil carbon and nitrogen cycling. Plantations and grassland differed significantly in functional gene profiles, bacterial diversity, and biogeochemical pool sizes. Most grassland profiles were similar, but plantation profiles generally differed from those of grasslands due to differences in functional gene abundance across diverse taxa. Eucalypts decreased ammonification and N fixation functional genes by 11% and 7.9% (P

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