Net greenhouse gas flux from agro-ecosystems for bioenergy

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Government and public support for biofuels and biomass-derived energy has been driven by the assumption that greenhouse gas (GHG) emissions will be reduced through their use. Assessment of bioenergy as a 'green' solution requires a better understanding of the net GHG emissions over the life-cycle of proposed agricultural feedstocks. The impact of biomass removal from agroecosystems on soil emissions of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) needs to be studied for a range of management systems. The long-term objectives of my research program are to quantify the contribution of agricultural feedstock production to the overall GHG emissions of bioenergy, and to identify soil and crop management practices that contribute to the environmental sustainability of these agro-ecosystems. We will measure net GHG emission (all three gases) from agro-ecosystems for bioenergy (eg. corn stover, miscanthus) using eddy covariance and tunable diode laser absorption spectroscopy (TDLAS). In addition, we will use field chambers and soil columns coupled with emissions of stable carbon isotopes using TDLAS to study carbon and nitrogen cycling in these agro-ecosystems. Particular attention will be placed on N2O emissions as affected by soil freeze/thaw given its importance for overall soil GHG emissions in Canada. Six graduate students (3 MSc and 3 PhD), five undergraduate students, and at least one post-doctoral fellow will be trained and conduct research using novel technologies. This research program will provide new knowledge linking soil processes with GHG emissions in these agro-ecosystems, datasets and models, which will be used in life-cycle analysis of bioenergy. Findings will have a significant impact on Canada's ability to predict GHG emissions from the agricultural sector.