Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): Jack W. McFarland; Roger W. Ruess; Knut Kielland; Kurt Pregitzer; Ronald Hendrick
    Date: 2010
    Source: Biogeochemistry. 99: 175-191
    Publication Series: Scientific Journal (JRNL)
    Station: Pacific Northwest Research Station
    PDF: View PDF  (2.88 MB)

    Description

    Free amino acids (FAA) constitute a significant fraction of dissolved organic nitrogen (N) in forest soils and play an important role in the N cycle of these ecosystems. However, comparatively little attention has been given to their role as labile carbon (C) substrates that might influence the metabolic status of resident microbial populations. We hypothesized that the residence time of simple C substrates, such as FAA, are mechanistically linked to the turnover of endogenous soil C pools. We tested this hypothesis across a latitudinal gradient of forested ecosystems that differ sharply with regard to climate, overstory taxon, and edaphic properties. Using a combined laboratory and field approach, we compared the turnover of isotopically labeled glycine in situ to the turnover of mineralizable soil C (Cmin) at each site. The turnover of glycine was rapid (residence times <2 h) regardless of soil type. However, across all ecosystems glycine turnover rates were strongly correlated with indices of soil organic matter quality. For example, C:N ratios for the upper soil horizons explained ~ 80% of the variability observed in glycine turnover, and there was a strong positive correlation between in situ glycine-C turnover and Cmin measured in the laboratory. The turnover of glycine in situ was better explained by changes in soil C availability than cross-ecosystem variation in soil temperature or concentrations of dissolved inorganic N and FAA-N. This suggests the consumption of these low-molecular-weight substrates by soil microorganisms may be governed as much by the overall decomposability of soil C as by N limitation to microbial growth.

    Publication Notes

    • You may send email to pnw_pnwpubs@fs.fed.us to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

    Citation

    McFarland, Jack W.; Ruess, Roger W.; Kielland, Knut; Pregitzer, Kurt; Hendrick, Ronald. 2010. Glycine mineralization in situ closely correlates with soil carbon availability across six North American forest ecosystems. Biogeochemistry. 99: 175-191.

    Keywords

    soil free amino acid, glycine, 13C, soil C and N, mineralizable C, forest soils

    Related Search


    XML: View XML
Show More
Show Fewer
Jump to Top of Page
https://www.fs.usda.gov/treesearch/pubs/38938