Investigating carbon and nitrogen: interactions in perennial systems on marginal land

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Land-use change and reliance on fossil fuels have decoupled carbon (C) and nitrogen (N) cycles, contributing to the accumulation of greenhouse gases (GHG) in the atmosphere. In a changing global environment with increased climate variability, maintaining agricultural productivity and reducing our reliance of fossil fuels remains a challenge. Using bioenergy crops is an innovative approach to address this challenge. Although ~15% of global energy production is currently derived from biomass, it is projected to account for 50% of global renewable energy sources by the year 2050. First generation bioenergy crops, derived from food crops such as corn, or the production of bioenergy crops on prime agricultural land solely is not ecologically sustainable and threatens global food security. This can be addressed by establishing perennial, or second generation, bioenergy crop systems (PBCS) on marginal land. Perennial bioenergy crops exploit and recycle nutrients through an extensive root system building soil C reserves and decreasing GHG emissions. However, this potential has not yet been well quantified and the mechanisms of interaction that regulate soil C and N dynamics in PBCS remains unexplored. This research program provides new knowledge on the long-term assimilation of C and characterizes temporal GHG emissions in fertilized and unfertilized PBCS on marginal land. It will also address the impact of freeze-thaw cycle (FTC) duration and temperature on GHG emissions and C and N dynamics. The methodological approach involves temporal GHG sampling and includes rigorous soil sampling and analysis. Investigating the interactions between GHG emissions and soil C and N dynamics concurrently enhances our understanding of PBCS management. This will also help advance our knowledge on the C sequestration and GHG emission potential of PBCS on marginal land. This information is essential when assessing the climate neutrality of PBCS and their potential incorporation into a carbon credit, or cap and trade program.