BioEnergy Research

, Volume 5, Issue 1, pp 124–138 | Cite as

Review and Model-Based Analysis of Factors Influencing Soil Carbon Sequestration Beneath Switchgrass (Panicum virgatum)

  • Charles T. GartenJr.Email author


A multi-compartment model was developed to summarize existing data and predict soil carbon sequestration beneath switchgrass (Panicum virgatum) in the southeastern USA. Soil carbon sequestration is an important part of sustainable switchgrass production for bioenergy because soil organic matter promotes water retention, nutrient supply, and soil properties that minimize erosion. A literature review was undertaken for the purpose of model parameterization. A sensitivity analysis of the model indicated that predictions of soil carbon sequestration were affected most by changes in aboveground biomass production, the ratio of belowground-to-aboveground biomass production, and mean annual temperature. Simulations indicated that the annual rate of soil carbon sequestration approached steady state after a decade of switchgrass growth while predicted mineral soil carbon stocks were still increasing. A model-based experiment was performed to predict rates of soil carbon sequestration at different levels of nitrogen fertilization and initial soil carbon stocks (to a 30-cm depth). At a mean annual temperature of 13°C, the predicted rate of soil carbon sequestration varied from −28 to 114 g C m−2 year−1 (after 30 years) and was greater than zero in 11 of 12 simulations that varied initial surface soil carbon stocks from 1 to 5 kg C m−2 and nitrogen fertilization from 0 to 18 g N m−2 year−1. The modeling indicated that more research is needed on the process of biomass allocation and on nitrogen loss from mature plantations, respectively, to improve our understanding of carbon and nitrogen dynamics in switchgrass agriculture.


Switchgrass Modeling Soil carbon Carbon sequestration Bioenergy Review 



Adjusted aboveground production


Nitrogen concentration in aboveground biomass


Annual aboveground nitrogen uptake


Annual aboveground production


Annual nitrogen inputs to the field


Aboveground biomass production without fertilization


Annual rate of soil carbon sequestration


Available soil nitrogen


Annual belowground nitrogen uptake


Annual belowground production


Initial soil carbon stock


Cumulative harvest of aboveground biomass


Coarse live root biomass


C/N ratio in coarse live roots


C/N ratio of fast soil carbon pool


Potential cumulative nitrogen loss


Cumulative nitrogen input


C/N ratio in five live roots


C/N ratio of slow soil carbon pool


Cumulative soil carbon sequestration


Annual atmospheric nitrogen deposition


Fraction of belowground biomass production allocated to fine live roots


Fraction of aboveground biomass removed during harvest (harvest efficiency)


Annual coarse live root mortality


Annual loss of fast soil carbon via decomposition


Annual fine live root mortality


Fertilization factor used to scale APP to AAP


Fine live root biomass


Fractional annual transfer of surface litter carbon to fast soil carbon


Fraction of initial soil carbon in the fast soil carbon pool


Fast soil carbon stock


Harvested aboveground biomass


Annual carbon transfer from coarse live roots to fast soil carbon


Annual carbon transfer from fine live roots to fast soil carbon


Annual loss of surface litter carbon via decomposition


Annual transfer of surface litter carbon to fast soil carbon


Total live belowground biomass


Surface litter carbon stock


Mean annual air temperature


Annual nitrogen fertilization


Potential annual nitrogen loss


Annual rate of net soil nitrogen mineralization


Annual net soil nitrogen mineralization


Nitrogen use efficiency


Annual plant nitrogen uptake from available soil nitrogen


Ratio of annual belowground-to-aboveground biomass production


Nitrogen translocation


Heterotrophic soil respiration


Root-to-shoot biomass ratio


Saturation limit for the slow soil carbon pool


Annual loss of slow soil carbon via decomposition


Soil nitrogen stock


Carbon stock in the mineral soil (excluding LSC)


Slow soil carbon stock


Annual flux of carbon from fast soil carbon to slow soil carbon


Annual transfer rate for carbon flux from fast soil carbon to slow soil carbon


Annual production of coarse live roots


Turnover time of coarse live roots


Annual production of fine live roots


Turnover time of fine live roots


Turnover time of fast soil carbon


Annual carbon inputs to surface litter


Turnover time of surface litter carbon


Turnover time of slow soil carbon



This research was sponsored by the US Department of Energy’s Office of Science, Biological and Environmental Research funding to the Consortium for Research on Enhancing Carbon Sequestration in Terrestrial Ecosystems, and performed at Oak Ridge National Laboratory (ORNL). ORNL is managed by UT-Battelle, LLC, for the US Department of Energy under contract DE-AC05-00OR22725. I wish to thank Stan Wullschleger (ORNL) and Mac Post (ORNL) for their helpful reviews of the draft manuscript.


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Copyright information

© Springer Science+Business Media, LLC. (outside the USA)  2011

Authors and Affiliations

  1. 1.Environmental Sciences DivisionOak Ridge National LaboratoryOak RidgeUSA

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