Forest soils in the northeastern United States store considerable amounts of carbon (C). With the increasing utilization of biomass as a “C-neutral” form of energy in the United States, these forests are susceptible to clear cutting and large losses of soil organic matter (SOM) to the atmosphere as carbon dioxide (CO2). The relative stability versus susceptibility of SOM to degradation can be approximated, in part, through the strength of organo-mineral interactions, that is, the strength of binding between SOM and mineral surfaces in the soil. This study investigated differences in SOM organo-mineral binding between northern hardwood forest stands with varying clear-cutting histories in Bartlett Experimental Forest in Bartlett, New Hampshire. Sequential chemical extractions were performed to quantify SOM storage in organo-mineral pools of various binding strength. In this case study, soils from Mature forest stands stored significantly more SOM in strongly mineral-bound and stable C pools than soils from Cut stands did. Differences in the relative distribution of C in organo-mineral pools in Mature and Cut forests may inform our understanding of SOM bioavailability, microbial decomposition, and CO2 production in ecosystems after clear cutting. These findings should contribute to discussions on long-term SOM stability in northeastern U.S. soils.
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1Environmental Studies Program, Dartmouth College, Hanover, NH.
2Department of Chemistry, Dartmouth College, Hanover, NH.
3Department of Biological Sciences, Dartmouth College, Hanover, NH.
Address for correspondence: Emily M. Lacroix, Dartmouth College, 6182 Steele Hall, Hanover, NH 03755. E-mail: firstname.lastname@example.org
Financial Disclosures/Conflicts of Interest: Dartmouth Undergraduate Research Fund and the Porter Family Fund. The authors declare no funding or conflicts of interest.
Authors’ contributions: E.M.L., A.F., and C.P. designed the study. A.F. and C.P. edited writing. C.P. and E.M.L. collected samples and corresponding field data. E.M.L. conducted laboratory analyses, analyzed data, and wrote the manuscript.
Received September 27, 2015.
Accepted for publication January 15, 2016.
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