Measuring soil greenhouse gas flux to predict arctic carbon flow and promote sustainable agriculture in the era of climate change.

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Climate change and human activity are altering carbon flows through soil ecosystems, but our understanding of the micro- and macro-scale drivers of soil greenhouse gas (GHG) emissions remains limited. In situ measurements of soil GHG flux in different environments or under different agricultural practices are one of the best tools for connecting information on belowground metabolism and microbial activity to their effect on global GHG budgets and climate change. We therefore require a portable trace gas analysis system (LI-COR LI-7810) capable of performing sensitive, real-time quantification of the soil-atmosphere flux of key GHGs, including CO2 and CH4. The LI-7810 will provide data that is crucial for accelerating the NSERC-funded research programs of L. Whyte, C. Kallenbach, J. Whalen, G. Clark, and C. Madramootoo. Whyte and Kallenbach will use the LI-7810 to collect GHG flux measurements from permafrost, permafrost thaw ponds, deglaciated soils, and other arctic habitats. As the arctic continues to warm due to climate change, the activity of soil microorganisms may accelerate or attenuate the release of GHGs in context-dependent ways. By complementing GHG flux measurements with analyses of soil chemistry and microbial activity, these projects will identify the biotic and abiotic controls on arctic GHG emissions and provide baseline data for predicting future GHG release.In the agricultural sector, Whalen and Madramootoo will use the LI-7810 to determine the effects of different fertilizers, soil supplements, and water management practices on soil GHG flux in experimental fields. Some soil supplements can be produced from organic waste, thus contributing to a circular economy, and Clark will explore how the use of processed organic residues as soil supplements increases or mitigates GHG flux. These projects are essential for improving agroecosystem management to reduce GHG emissions. Finally, Kallenbach, Clark, and Madramootoo will explore the effects of intermittent flooding and freeze/thaw cycles on agricultural GHG emissions. Climate change is making these events increasingly common, and an understanding of how these events affect belowground microbial processes and soil GHG emissions will facilitate the development of management practices that can help mitigate flood- and freeze/thaw-induced GHG release. Overall, the data we obtain from the LI-7810 will inform environmental and agricultural sciences and policies in Canada and throughout the world. We expect ~18 HQP/year will learn to measure and interpret GHG flux at various ecosystem levels, resulting in a new generation of competitive HQP in microbial ecology, soil science, agri-food practices, and waste management. These HQP will be poised to provide their expertise to future employers in areas including research, regulatory affairs, field applications, consulting, and teaching. If instrument time permits, we will also make the equipment available to HQP from other labs in our fields.