Dissertation Research: Soil Aggregation and Ecosystem Function

土壤团聚体是一组结合在一起形成更大结构单元的土壤颗粒，可能是土壤中碳和氮循环的重要调节因素。聚集体在物理上保护有机物免受微生物氧化，并提供可能有利于温室气体产生的微生境。团聚体结构通常在耕作等土壤干扰后丢失，团聚体结构的恢复有助于缓解与碳和氮循环有关的环境问题。受干扰的生态系统中碳和氮的加速转化导致了一系列环境问题，包括温室气体积累、地下水污染和土壤侵蚀。本研究将沿着扰动梯度考察同一土壤系列上的十个生态系统中的土壤团聚体及其对碳、氮循环的影响。这些系统的范围从集约化管理的行作物农业到后期演替的森林。这项研究将检验关于土壤碳储量、微量气体通量和微生物种群结构的团聚体的恢复和分解的假设。

Soil aggregates, groups of soil particles bound together into a larger structural unit, may be important regulators of carbon and nitrogen cycling in soil. Aggregates physically protect organic matter from microbial oxidation and provide microsite habitats that may favor greenhouse gas production. Aggregate structure is typically lost following soil disturbances such as tillage, and the recovery of aggregate structure could help mitigate environmental problems related to carbon and nitrogen cycling. Accelerated carbon and nitrogen transformations in disturbed ecosystems contribute to a number of environmental problems, including greenhouse gas accumulation, groundwater contamination, and soil erosion. This research will examine soil aggregation and its effects on carbon and nitrogen cycling in ten ecosystems on the same soil series along a disturbance gradient. The systems range from intensively managed, row crop agriculture to late successional forests. The research will test hypotheses about the recovery and breakdown of aggregates on soil carbon storage, trace gas fluxes, and microbial population structure.