Improved understanding of soil organic matter stabilization in agricultural systems with contrasting input strategies.

我的研究计划的长期目标是了解如何土壤有机质（SOM）的组成和分布在景观可以管理，以促进可持续的农业生态系统。建议增加土壤有机质，以发展健康的土壤。人们还经常认为，健康的土壤能够更好地抵抗环境压力。这一点变得越来越重要，因为气候模型预测更频繁和更严重的天气事件，沿着加拿大最具农业生产力的地区的总体变暖趋势。土壤有机质（SOM）的稳定性与其抗微生物降解能力有关，对养分循环、温室气体排放、土壤侵蚀控制和固碳具有重要意义。大多数研究讨论了总有机质对健康和有弹性的土壤的贡献，然而，我们知道，SOM是异质的。土壤有机质的组成受植物和动物残留物（或输入）的类型和数量的影响。由于有机质的分子结构影响其在环境中的持久性，这是至关重要的，以了解这些输入如何影响有机质的组成，因为它具有重要的意义，养分循环，温室气体排放，侵蚀控制和C封存。我的研究专长结合了对土壤系统的深刻理解和用于了解生态系统对SOM生物化学的影响的最先进的仪器。在这个建议中，我使用这些先进的方法来探讨不同的农业投入策略如何有助于SOM的整体组成。总体目标是确定SOM管理战略，将有助于农业生态系统的可持续性和恢复力。本研究的具体目标是：1）建立作物和粪肥碳输入对土壤有机质生物稳定性的影响关系; 2）阐明土壤有机质热稳定性与微生物基质利用效率之间的关系; 3）利用先进的光谱技术确定不同有机输入类型和数量下土壤关键有机质组成的差异;（4）设计了一个包括微生物、生态系统和化学控制的农业生态系统有机质循环过程模型。这项工作的结果将有显着的影响，我们从根本上了解土壤有机质的投入有助于SOM稳定的机械性质。由于本研究中选择用于表征的土壤将来自一系列土地管理实践，因此我们将能够为可持续农业实践提出强有力的、基于科学的建议。最终，这将使人们更好地了解农业生态系统如何固碳，并使其不受气候和天气事件不确定性和可变性增加的影响。

The long-term objectives of my research program are to understand how soil organic matter (SOM) composition and distribution in the landscape can be managed to promote sustainable agro-ecosystems. Soil organic matter buildup is recommended to develop healthy soils. It is also frequently suggested that healthy soils are better able to resist environmental stresses. This is becoming increasingly important as climate models are predicting more frequent and severe weather events, along with a general warming trend for the most agriculturally productive regions in Canada. The stability of soil organic matter (SOM) as it relates to resistance to microbial degradation has important implications for nutrient cycling, emission of greenhouse gases, erosion control and C sequestration. Most studies discuss the contributions of total SOM toward healthy and resilient soils; however, we know that SOM is heterogeneous. SOM composition is influenced by the types and amounts of plant and animal residues (or inputs) that the soil receives. Since the molecular structure of SOM influences its persistence in the environment, it is critical to understand how these inputs influence SOM composition because it has important implications for nutrient cycling, emission of greenhouse gases, erosion control and C sequestration. My research expertise combines a strong understanding of soil systems and state-of-the-art instrumentation used to understand ecosystem influences over the biogeochemistry of SOM. In this proposal, I use these advanced methods explore how different agricultural input strategies contribute to the overall composition of SOM. The overall goal is to identify SOM management strategies that would contribute to agroecosystem sustainability and resilience. The specific objectives of this proposal are: 1) Establish link between carbon inputs from crops and manure on the biological stability of SOM; 2) Elucidate the relationship between thermal stability of SOM and microbial substrate use efficiency; 3) Identify key organic matter composition differences from soils under contrasting organic input types and amounts using advanced spectroscopy; 4) design a process model which includes microbial, ecosystem and chemical controls over SOM cycling in agroecosystems. Findings from this work will have a significant impact on our fundamental understanding of how soil organic matter from inputs contributes to the mechanistic nature of SOM stability. Because soils selected for characterization in this study will come from a range of land management practices, we will be able to make robust, science-based recommendations for sustainable agricultural practices. Ultimately, this will lead to a better understanding of how agroecosystems can sequester carbon and be future-proofed against increased uncertainty and variability in climate and weather events.