Author ORCID Identifier
Semester
Fall
Date of Graduation
2025
Document Type
Dissertation
Degree Type
PhD
College
Davis College of Agriculture, Natural Resources and Design
Department
Division of Plant and Soil Sciences
Committee Chair
Ember Morrissey
Committee Member
James Kotcon
Committee Member
Edward Brzostek
Committee Member
Charlene Kelley
Committee Member
Sven Verlinden
Abstract
The sustainability of agricultural landscapes depends on understanding the complex interactions between plants, soil, and microbes. In Appalachia, a region shaped by complex terrain and long histories of human and ecological interaction, small family farms produce hay, livestock, and row crops. These agroecosystems, though often treated as “artificial” by many ecologists, have the potential to support both food production and biodiversity conservation if managed with an understanding of ecological complexity. This dissertation examines how plant and microbial diversity interact with soil and management to influence nutrient cycling, soil health, and long-term resilience in Appalachian agricultural systems. A literature review revealed a disconnect between ecological and agronomic perspectives on plant diversity: ecological studies demonstrate links between diverse grasslands and soil carbon gains, whereas short-term agronomic trials often yield conflicting results. Applied, long-term research is needed to bridge these gaps. A state-wide survey of West Virginia pastures documented low diversity, few legumes, and further drought-driven homogeniziation in pastures towards tall fescue dominance. We then explored how soil microbial diversity affects macroaggregate stability using PLFA and SLAKES, finding that Actinobacteria, rather than mycorrhizal fungi, were most strongly associated with soil stabilization, suggesting complementary roles of soil microbes in erosion prevention and soil health. We also quantified rhizosphere bacterial assimilation of fertilizer nitrogen in maize using quantitative stable isotope probing (qSIP), comparing field and laboratory incubations. We identified the microbial taxa most adept at nitrogen assimilation in the maize rhizosphere, such as Chitinophaga, and showed that microbial responses differ across incubation contexts, highlighting the importance of studying organisms within their ecological networks. Specifially, field incubations best capture the activity of plant-associated microbes, though overall assimilation rates were lower in the field than in the lab. These studies demonstrate that fostering biodiversity, across plants and microbes, can strengthen soil health and build resilience in agroecosystems, offering a pathway toward sustainable agriculture under changing environmental conditions.
Recommended Citation
Reed Close, Kinsey, "Microbial and plant biodiversity in Appalachian agroecosystems and their implications for soil health" (2025). Graduate Theses, Dissertations, and Problem Reports. 13096.
https://researchrepository.wvu.edu/etd/13096
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Beef Science Commons, Biochemistry Commons, Biodiversity Commons, Botany Commons, Environmental Microbiology and Microbial Ecology Commons, Molecular Biology Commons, Population Biology Commons