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): D.S. Ross; S.W. Bailey; R.D. Briggs; J. Curry; I.J. Fernandez; G. Fredriksen; C.L. Goodale; P.W. Hazlett; P.R. Heine; C.E. Johnson; J.T. Larson; G.B. Lawrence; R.K. Kolka; R. Ouimet; D. Pare; D. deB Richter; C.D. Schirmer; R.A. Warby
    Date: 2015
    Source: Ecosphere. 6(5): 73.
    Publication Series: Scientific Journal (JRNL)
    Station: Northern Research Station
    PDF: Download Publication  (2.22 MB)


    Long-term forest soil monitoring and research often requires a comparison of laboratory data generated at different times and in different laboratories. Quantifying the uncertainty associated with these analyses is necessary to assess temporal changes in soil properties. Forest soil chemical properties, and methods to measure these properties, often differ from agronomic and horticultural soils. Soil proficiency programs do not generally include forest soil samples that are highly acidic, high in extractable Al, low in extractable Ca and often high in carbon. To determine the uncertainty associated with specific analytical methods for forest soils, we collected and distributed samples from two soil horizons (Oa and Bs) to 15 laboratories in the eastern United States and Canada. Soil properties measured included total organic carbon and nitrogen, pH and exchangeable cations. Overall, results were consistent despite some differences in methodology. We calculated the median absolute deviation (MAD) for each measurement and considered the acceptable range to be the median ± 2.5 × MAD. Variability among laboratories was usually as low as the typical variability within a laboratory. A few areas of concern include a lack of consistency in the measurement and expression of results on a dry weight basis, relatively high variability in the C/N ratio in the Bs horizon, challenges associated with determining exchangeable cations at concentrations near the lower reporting range of some laboratories and the operationally defined nature of aluminum extractability. Recommendations include a continuation of reference forest soil exchange programs to quantify the uncertainty associated with these analyses in conjunction with ongoing efforts to review and standardize laboratory methods.

    Publication Notes

    • Check the Northern Research Station web site to request a printed copy of this publication.
    • Our on-line publications are scanned and captured using Adobe Acrobat.
    • During the capture process some typographical errors may occur.
    • Please contact Sharon Hobrla, if you notice any errors which make this publication unusable.
    • 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.


    Ross, D.S.; Bailey, S.W.; Briggs, R.D.; Curry, J.; Fernandez, I.J.; Fredriksen, G.; Goodale, C.L.; Hazlett, P.W.; Heine, P.R.; Johnson, C.E.; Larson, J.T.; Lawrence, G.B.; Kolka, R.K.; Ouimet, R.; Pare, D.; Richter, D. deB.; Schirmer, C.D.; Warby, R.A. 2015. Inter-laboratory variation in the chemical analysis of acidic forest soil reference samples from eastern North America. Ecosphere. 6(5): 73.


    Google Scholar


    aluminum, calcium, carbon, forest soils, inter-laboratory variability, laboratory methods, pH, reference soils, soil analysis, Uncertainty Analysis, uncertainty

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page