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

土地利用变化和对化石燃料的依赖使碳(C)和氮(N)循环脱钩，导致大气中温室气体（GHG）的积累。在气候变化加剧的全球环境中，保持农业生产力和减少对化石燃料的依赖仍然是一项挑战。使用生物能源作物是解决这一挑战的一种创新方法。虽然目前全球约15%的能源生产来自生物质能，但预计到2050年，它将占全球可再生能源的50%。从玉米等粮食作物中提取的第一代生物能源作物，或者仅仅在优质农业用地上生产生物能源作物，在生态上是不可持续的，并威胁到全球粮食安全。这可以通过在边缘土地上建立多年生或第二代生物能源作物系统（PBCS）来解决。多年生生物能源作物通过广泛的根系利用和循环养分，建立土壤C储备，减少温室气体排放。然而，这种潜力尚未被很好地量化，并且调节PBCS土壤C和N动态的相互作用机制仍未被探索。本研究项目提供了关于边缘土地上施肥和未施肥PBCS对C的长期同化和温室气体排放特征的新知识。研究还将探讨冻融循环持续时间和温度对温室气体排放和碳氮动态的影响。方法方法涉及时间温室气体取样，包括严格的土壤取样和分析。研究温室气体排放与土壤C和N动态之间的相互作用，同时增强了我们对PBCS管理的理解。这也将有助于提高我们对边际土地上PBCS固碳和温室气体排放潜力的认识。在评估PBCS的气候中和性及其纳入碳信用或限额与交易计划的可能性时，这些信息至关重要。

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.