DISSERTATION RESEARCH: Does grazing stimulate root exudation and accumulation of soil carbon in perennial grasslands?

该项目的目标是确定控制美国东南部牧场土壤中碳吸收和储存的因素。被同位素标记的碳分子将被跟踪并用于回答有关植物根和土壤微生物如何以及在哪里隔离碳的问题。将解决的两个主要问题是：植物如何将内部碳从根部转移到土壤中，以及土壤中的微生物如何决定这些碳是通过呼吸迅速释放回大气，还是稳定并长期储存？长期储存在土壤中的碳对健康生态系统的运行至关重要，在这种情况下，这是美国重要的农业系统，但管理者和政策制定者也感兴趣，因为它代表了生态系统储存大气中碳的力量。至少有助于抵消人类活动碳排放的一个有希望的战略是加强草原土壤对碳的吸收和储存能力，因为它们在全球范围内广泛存在，对农业生产也至关重要。该项目将促进对草原土壤碳储量调节过程的技术理解。其他成果包括研究生培训、跨科学学科合作的机会、对本科生的指导和教育，以及成果的推广，以帮助农场管理者了解并提高他们在农场储存碳的能力，同时还改善牧场的可持续性。

The goal of this project is to identify factors that regulate the uptake and storage of carbon within soils of cattle pastures in the southeastern United States. Carbon molecules that have been isotopically labeled will be tracked and used to answer questions about how and where carbon is sequestered by plant roots and soil microbes. The two main questions that will be addressed are: how plants transfer internal carbon from roots to the soil, and how microbes in the soil determine whether that carbon is quickly released back to the atmosphere through respiration or stabilized and stored for long periods of time? Carbon stored in soils for long periods of time is critical for the functioning of healthy ecosystems, in this case important agricultural systems in the US, but is also of interest for managers and policy makers because it represents the strength of the ecosystem for storing carbon from the atmosphere. One promising strategy to at least help offset carbon emissions from human activities is to strengthen the uptake and storage capacity for carbon in the soils of grasslands, since they are globally extensive and also vital for agricultural production. This project will advance technical understanding of the processes that regulate grassland soil carbon storage. Additional outcomes include graduate student training, opportunities for collaboration across scientific disciplines, mentoring and education of undergraduate students, and the extension of results to help farm managers understand and increase their abilities to store carbon on-farm while also improving pasture sustainability.