Greenhouse Gas Emissions of Biofuel Cropping Systems: Separating Root-Derived Respiration From Soil CO2 Efflux Using Shading.

Biofuel cropping systems are currently being evaluated for their potential to mitigate climate change through sequestering carbon and reducing GHG emissions.  Soil CO2 effluxes are a common component of these studies. Partitioning measured soil CO2 effluxes into root- and soil-derived constituents is essential in order for the measurements to be interpreted with respect to greenhouse gas emissions and carbon budgets. Disrupting the flow of photosynthates to roots via shading shows great potential as a non-destructive method of separation. In this study we used 3 levels of shading on a continuous corn, un-fertilized tall-grass prairie, and N fertilized prairie. We looked to isolate the effects of plant photosynthesis on soil CO2 emissions.