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Research article - Peer-reviewed, 2022

Beyond bulk: Density fractions explain heterogeneity in global soil carbon abundance and persistence

Heckman, Katherine; Pries, Caitlin E. Hicks; Lawrence, Corey R.; Rasmussen, Craig; Crow, Susan E.; Hoyt, Alison M.; von Fromm, Sophie F.; Shi, Zheng; Stoner, Shane; McGrath, Casey; Beem-Miller, Jeffrey; Berhe, Asmeret Asefaw; Blankinship, Joseph C.; Keiluweit, Marco; Marin-Spiotta, Erika; Monroe, J. Grey; Plante, Alain F.; Schimel, Joshua; Sierra, Carlos A.; Thompson, Aaron; Wagai, Rota
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Understanding the controls on the amount and persistence of soil organic carbon (C) is essential for predicting its sensitivity to global change. The response may depend on whether C is unprotected, isolated within aggregates, or protected from decomposition by mineral associations. Here, we present a global synthesis of the relative influence of environmental factors on soil organic C partitioning among pools, abundance in each pool (mg C g(-1) soil), and persistence (as approximated by radiocarbon abundance) in relatively unprotected particulate and protected mineral-bound pools. We show that C within particulate and mineral-associated pools consistently differed from one another in degree of persistence and relationship to environmental factors. Soil depth was the best predictor of C abundance and persistence, though it accounted for more variance in persistence. Persistence of all C pools decreased with increasing mean annual temperature (MAT) throughout the soil profile, whereas persistence increased with increasing wetness index (MAP/PET) in subsurface soils (30-176 cm). The relationship of C abundance (mg C g(-1) soil) to climate varied among pools and with depth. Mineral-associated C in surface soils (<30 cm) increased more strongly with increasing wetness index than the free particulate C, but both pools showed attenuated responses to the wetness index at depth. Overall, these relationships suggest a strong influence of climate on soil C properties, and a potential loss of soil C from protected pools in areas with decreasing wetness. Relative persistence and abundance of C pools varied significantly among land cover types and soil parent material lithologies. This variability in each pool's relationship to environmental factors suggests that not all soil organic C is equally vulnerable to global change. Therefore, projections of future soil organic C based on patterns and responses of bulk soil organic C may be misleading.


climate change; persistence; radiocarbon; soil carbon; soil fractions; soil organic matter; terrestrial carbon cycle

Published in

Global Change Biology
2022, volume: 28, number: 3, pages: 1178-1196
Publisher: WILEY

Authors' information

Heckman, Katherine
United States Department of Agriculture (USDA)
Pries, Caitlin E. Hicks
Dartmouth College
Lawrence, Corey R.
United States Geological Survey
Rasmussen, Craig
University of Arizona
Crow, Susan E.
University of Hawaii Manoa
Hoyt, Alison M.
Lawrence Berkeley National Laboratory
Hoyt, Alison M.
Max Planck Society
von Fromm, Sophie F.
ETH Zurich
von Fromm, Sophie F.
Max Planck Society
Shi, Zheng
United States Department of Energy (DOE)
Stoner, Shane
Max Planck Society
Stoner, Shane
ETH Zurich
McGrath, Casey
University of Hawaii Manoa
Beem-Miller, Jeffrey
Max Planck Society
Berhe, Asmeret Asefaw
University of California Merced
Blankinship, Joseph C.
University of Arizona
Keiluweit, Marco
University of Massachusetts Amherst
Marin-Spiotta, Erika
University of Wisconsin Madison
Monroe, J. Grey
University of California Davis
Plante, Alain F.
University of Pennsylvania
Schimel, Joshua
University of California Santa Barbara
Swedish University of Agricultural Sciences, Department of Ecology
Max Planck Institute for Biogeochemistry
Thompson, Aaron
University of Georgia
Thompson, Aaron
University System of Georgia
Wagai, Rota
National Agriculture and Food Research Organization - Japan
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Sustainable Development Goals

SDG15 Life on land
SDG13 Climate action

UKÄ Subject classification

Soil Science

Publication Identifiers


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