Beginning in FY07, CSiTE reorganized around seven scientific themes and coordinated research activities at field experiments in switchgrass ecosystems managed for biomass production at Milan, Tennessee, and the Fermilab site at Batavia, Illinois.
The seven themes (Figure 1)  are:

1) Soil carbon inputs

2) Soil structural controls

3) Microbial community function and dynamics,

4) Humification chemistry,

5) Intrasolum carbon transport,

6) Mechanistic modeling

7) Integrated evaluation

Theme Overview Diagram
Figure 1. The seven research themes of CSiTE and their relationships to each other.


Each of the five experimental theme’s research contributes to the sixth theme, Mechanistic Modeling which allows us to explore the effects of different processes, carbon inputs, and environmental conditions on enhancing of carbon sequestration at a local scale. The seventh theme, Integrated Evaluation of Carbon Sequestration Technologies, draws upon the Mechanistic Modeling theme for estimates of potential soil C sequestration across the wide range of soils, climate, and crops and management regimes possible in the U.S. By combining those estimates with the greenhouse gas (GHG) emissions and the economic value of those crops and management regimes, the seventh theme explores the economic consequences and GHG benefits for various strategies to enhance soil C sequestration at the national scale.


For the five experimental themes we have selected: 

•     An Alfisol located in western Tennessee (Milan) as our primary test soil type and a Mollisol located in northeastern Illinois (Fermilab) as our secondary test soil type. As research evolves we will explore other soils.
•     Switchgrass ecosystems managed for cellulosic biomass production as our testbed ecosystem. We intend that poplar ecosystems be addressed in later years.
•     Manipulations of C input and soil conditions to affect C sequestration processes at the sites.

We use the Erosion Productivity Impact Calculator (EPIC) (Izaurralde et al. 2006) as the basis of our mechanistic modeling activities. We use the systems modeling language STELLA® as a tool to engage the experimental scientists in building the conceptual and quantitative links among the five experimental themes in a way that can then be incorporated into the more multidimensional EPIC model and as a means for conducting model-based experiments for testing hypotheses about predicted effects of genotypic and environmental factors on soil C accrual.. The Forest and Agriculture Sector Optimizing Model (FASOM) model (McCarl and Schneider 2001), which is already integrated with EPIC and depicts total U.S. agricultural and forestry activities over time incorporating GHG issues of permanence, leakage, and additionality, forms the basis for our regional- to national-scale analysis of developed and potential soil C sequestration enhancement opportunities. 


Research across all seven themes coalesces around the experimental switchgrass ecosystems managed for biomass production and is designed to address five overarching scientific questions:


I.    What is the nature of belowground C inputs by switchgrass, and are they compatible with sustained aboveground biomass production and soil C sequestration?

II.   What are the fundamental physical, chemical, and microbial mechanisms controlling C accrual and storage in soil, and how do they interact in space and time?

III. What processes control the movement and distribution of C through the soil profile?


IV.  How are the fundamental processes controlling C distribution and movement manifested across landscapes and time?

V.   How can fundamental knowledge best be used to identify and implement methods and practices for sustained enhancement of soil C in the context of biomass production for energy in an environmentally acceptable and economically feasible fashion?



Model Focus Diagram

Figure 2. Approach for transforming experimentally derived understanding to forecasting capabilities

CSiTE seeks to ensure that its fundamental science findings are used to inform and improve carbon sequestration forecasting capabilities by taking a vertically integrated approach which links field experiments to conceptual models, and conceptual models to forecasting models and regional models.  (Figure 2).  In this manner CSiTE strives to contribute to the effective application of carbon sequestration technologies to mitigate CO2-induced climate change. 



Click on a Theme to Expand. Click again to Close.

Theme 1. Soil carbon inputs – lead by Chuck Garten and Stan Wullschleger (genetics)

Theme 2. Soil structural controls – lead by Julie Jastrow

Theme 3. Microbial community function and dynamics – lead by Mike Miller

Theme 4. Humification chemistry – lead by Jim Amonette,

Theme 5. Intrasolum carbon transport – lead by Phil Jardine

Theme 6. Mechanistic modeling – lead by Mac Post

Theme 7. Integrated evaluation – lead by Ron Sands