Date of Award:

12-2025

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Biology

Committee Chair(s)

Michelle Baker (committee chair) Bonnie Waring (committee co-chair)

Committee

Michelle Baker

Committee

Bonnie Waring

Committee

Brooke Osborne

Committee

Yong Zhou

Committee

Jennifer Reeve

Abstract

Climate change and its cascading effects are driven by increases in atmospheric carbon dioxide (CO2). Many climate solutions exists to remove this excess carbon (C) from the atmosphere, and soils, in particular, represent one of the few win-win solutions. Soils play a vital role in the global C cycle because they store more C than plants and the atmosphere combined, however, they also release more CO2 annually than fossil fuel combustion (a major contributor to accelerating climate change). Therefore, preventing CO2 loss from soil could help slow the progression of climate change, and increasing overall soil C storage could even help reverse climate change. Furthermore, improving soil C stocks in natural and managed systems is associated with many co-benefits, including (but not limited to) greater plant growth, suggesting that soil C sequestration may result in greater crop production, enhanced ecosystem resilience, and potentially greater biodiversity.

And while soil C sequestration may help ameliorate many of the world’s environmental problems, a better understanding of how soil C is lost and gained under different conditions is required to implement large scale C sequestration practices. In this dissertation, I used a combination of laboratory and field experiments to better understand 1) conflicting soil C responses to nitrogen (N) deposition, 2) how soil pH changes microbial decomposition and if those changes alter soil C losses and gains, and 3) if cattle grazing can be used to increase plant growth in rangelands and facilitate soil C sequestration. Collectively, this dissertation advances our understanding of mechanisms controlling soil C responses to climate change, while also demonstrating that large scale soil C sequestration is readily feasible.

Included in

Biology Commons

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