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管理土壤有机质（SOM）的组成和分布，以促进可持续的农业生态系统。建议增加土壤有机质，以发展健康土壤。人们还经常提出，健康的土壤能够更好地抵抗环境压力。随着气候模型预测更频繁和更恶劣的天气事件，以及加拿大最具农业生产力地区普遍变暖的趋势，这一点变得越来越重要。土壤有机质（SOM）稳定性与微生物降解能力有关，对养分循环、温室气体排放、侵蚀控制和碳固存具有重要意义。大多数研究讨论了总SOM对健康和弹性土壤的贡献；然而，我们知道SOM是异构的。土壤吸收的植物和动物残留物（或输入物）的种类和数量会影响土壤有机质的组成。由于SOM的分子结构影响其在环境中的持久性，因此了解这些输入如何影响SOM的组成至关重要，因为它对养分循环、温室气体排放、侵蚀控制和碳封存具有重要意义。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生物地球化学影响的最先进仪器。在本提案中，我使用这些先进的方法探讨了不同的农业投入策略如何对SOM的整体构成做出贡献。总体目标是确定有助于农业生态系统可持续性和复原力的SOM管理战略。本提案的具体目标是：1)建立作物碳输入与粪肥对土壤有机质生物稳定性的联系；2)阐明SOM热稳定性与微生物底物利用效率的关系；3)利用先进光谱技术识别不同有机输入类型和量下土壤的关键有机质组成差异；4)设计一个包括微生物、生态系统和化学对农业生态系统中SOM循环控制的过程模型。这项工作的发现将对我们对土壤有机质如何促进土壤有机质稳定性的机制性质的基本理解产生重大影响。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，这将使我们更好地了解农业生态系统如何封存碳，以及如何抵御气候和天气事件中日益增加的不确定性和可变性。

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.