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Title: A call for international soil experiment networks for studying, predicting, and managing global change impacts

The soil profile encompasses a remarkably large range of biogeochemical conditions, processes, and fluxes. For example, in most soils the turnover time of soil organic carbon (SOC) varies more between the soil surface and 1m deep than between surface soils in the tropics vs. the Arctic (Torn et al., 2009). Moreover, radiocarbon observations in different soil types show that SOC decomposition rates decrease with depth, with residence times of years to decades at the soil surface to over 10 000 years at 1m deep (e.g., Torn et al., 2002). There are many competing hypotheses for this steep decline in SOC turnover with depth. They can be grouped loosely into physical–chemical accessibility, energetic limits to microbial activity, microclimate and pH, and physical disconnect between decomposers and substrate. While all of these mechanisms control deep SOC cycling, data are lacking for unraveling their relative importance in different soils under different environmental conditions. However, critical knowledge for predicting soil responses to global change, because fairly rapid loss (or gain) of old and/or deep SOC stocks is possible and more than 80% of the world’s SOC is found below 20 cm depth (Jobbágy and Jackson, 2000). Currently, the soil modules within Earth system modelsmore » are parameterized for surface soil and lack mechanisms important for stabilization and losses of deep SOC. We, therefore, suggest that a critical challenge is to achieve process-level understanding at the global level and the ability to predict whether, and how, the large stores of deep, old SOC are stabilized and lost under global change scenarios.« less
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [1] ;  [7] ; ORCiD logo [8] ;  [9] ;  [10] ;  [11]
  1. Univ. of California, Berkeley, CA (United States)
  2. National Institute of Agricultural Research (INRA), Lusignan (France); Inst. of Ecology of Environmental Sciences, Thiverval-Grignon (France)
  3. Stockholm Univ. (Sweden)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  5. Univ. of Antwerp, Wilrijk (Belgium)
  6. Univ. of Oklahoma, Norman, OK (United States)
  7. Inst. of Ecology of Environmental Sciences, Thiverval-Grignon (France)
  8. Univ. of Zurich (Switzerland)
  9. Swiss Federal Inst. of Technology, Zurich (Switzerland)
  10. Max Planck Society, Jena (Germany). Max Planck Inst. for Biogeochemistry
  11. Univ. of California, Berkeley, CA (United States); Peking Univ., Beijing (China)
Publication Date:
OSTI Identifier:
1212486
Grant/Contract Number:
AC05-00OR22725; AC02-05CH11231; 312690; ANR-11-INBS-0001
Type:
Published Article
Journal Name:
SOIL
Additional Journal Information:
Journal Volume: 1; Journal Issue: 2; Journal ID: ISSN 2199-398X
Publisher:
European Geosciences Union/Copernicus
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 58 GEOSCIENCES