Submitted to: Meeting Abstract
Publication Type: Abstract only
Publication Acceptance Date: 1/3/2011
Publication Date: 1/31/2011
Citation: Zeri, M., Anderson-Tiexeira, K., Hickman, G., Masters, M., Delucia, E., Bernacchi, C.J. 2011. Net carbon uptake by establishing biofuel crops in Central Illinois. AmeriFlux Science Meeting and 3rd NACP All Investigators Meeting. #C-61. Interpretive Summary:
Technical Abstract: Clean and renewable sources of energy as wind, solar or biofuels comprise a valuable set of options available to deal with the pressing topics of energy security and mitigation of climate change effects. However, the efficiency in energy conversion and the environmental impacts of each new source of energy should be assessed. Crop-based biofuels are an option for replacing ethanol production from maize (Zea mais) since some species can yield more biomass while sequestering carbon into the soil. The energy balance closure and the carbon balance were investigated over four biofuel crops in Central Illinois, USA, for 2008 and 2009. The species chosen in this comparison were maize, miscanthus (Miscanthus x giganteus), switchgrass (Panicum virgatum) and a mixture of native prairie plants. The fields are 4 ha in size and measurements included the eddy covariance technique, soil chambers and biometric samplings. The energy balance closure varied from 83% to 98%, indicating that significant differences in the closure can be observed even when using replicated measurements systems on side-by-side fields. Mowing of weeds for establishment of the native prairie and switchgrass in the first year impacted the net flux of CO2, reducing or reversing the net exchanges of carbon due to the disturbances in the soil. Switchgrass established very well and had the highest net uptake of carbon in the second year. Net biome production calculated between 2008 and 2009 revealed that maize was a source of carbon (NBP of -153 g C m-2) after the harvest of grain, while miscanthus was close to neutral (-13.3 g C m-2). Miscanthus was still in the establishment phase and the neutral balance was expected. Switchgrass and prairie were sinks of carbon in the period, sequestering 245 g C m-2 and 136 g C m-2, respectively.