Dissertation
Deep Soil Microbial Ecology: Relationships Between Biotic And Abiotic Properties In Arid And Semi-Arid Soil Profiles
Washington State University
Doctor of Philosophy (PhD), Washington State University
2022
DOI:
https://doi.org/10.7273/000005108
Abstract
Deep soil health is important to dryland cropping systems in arid and semi-arid areas. For example, in Washington State and the larger inland Pacific Northwest, winter and perennial wheat cropping systems and associated microbiomes rely on water, soluble nutrients, and translocated resources that can accumulate in deep soil horizons. However, deep soil microbial ecology in these systems is not well understood. To investigate relationships between the soil microbial community and soil chemistry, we sampled deep soil cores from: the Palouse soil series (0-85 cm soil depth) from long-term dryland winter wheat and perennial wheatgrass sites in the Palouse River Watershed (Chapters 2 and 3); and the Warden soil series (0-100 cm) from an irrigated perennial wheatgrass site in the Columbia Basin (Chapter 4). In both soils, deep horizons had higher soil pH, exchangeable calcium and magnesium concentrations, and lipid saturation compared to surface soils. In the Palouse soil series, deep horizons had highest relative abundance (%) of Gram(+) bacterial phospholipid fatty acids (PLFAs) and lowest abundance of fungal and Gram(-) bacterial PLFAs compared to surface soils. In the Warden soil series, deep horizons had highest levels of several organic acids, triacylglycerols, and inorganic carbon in the form of calcium carbonates and lowest abundance of several simple sugars and sugar alcohols. Also in Warden soils, there were strong depth effects on untargeted soil multi-omics that signal osmotic and oxidative stress that were not reflected in compositional shifts in the soil microbial community assessed via amplicon sequencing of 16S (bacteria and archaea) and ITS (fungi) genes. Changes in smaller, extractable carbon and nitrogen pools in Palouse soils were also observed. These studies highlighted the importance of targeting specific carbon and nitrogen pools and metabolites instead of total pools or bulk measures, based on the research question and system under study. This research illustrates the value in sampling at least one meter deep to understand microbial and plant interactions with soil carbon and nitrogen in arid and semi-arid soils. Understanding deep soil ecology will be imperative to further soil health management practices that promote long-term carbon sequestration in low water and resource environments.
Metrics
12 File views/ downloads
32 Record Views
Details
- Title
- Deep Soil Microbial Ecology
- Creators
- Katherine Naasko
- Contributors
- Haiying Tao (Advisor)John P Reganold (Advisor)David R Huggins (Committee Member)Tarah S Sullivan (Committee Member)William Lee Pan (Committee Member)Kirsten S Hofmockel (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Crop and Soil Sciences, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 217
- Identifiers
- 99901019940301842
- Language
- English
- Resource Type
- Dissertation