Thesis
Effects of biochar and mycorrhizal fungi on the survival and growth of two native plant species in contaminated mine soil
Washington State University
Master of Science (MS), Washington State University
12/2020
DOI:
https://doi.org/10.7273/000004217
Handle:
https://hdl.handle.net/2376/118554
Abstract
Although inoculations with mycorrhizal fungi have been used successfully to promote native plant growth in ecological restorations, the restoration of highly contaminated sites such as those affected by mining operations, remains a challenge. High concentrations of heavy metals, soil compaction, acidic pH and low organic matter are common attributes of abandoned mine landscapes that can impede plant establishment and survival. Soil treatments such as mycorrhizal fungi and biochar individually can promote plant survival by mitigating these environmental pressures, however, it is largely unknown whether there are synergistic effects of mycorrhizal fungi and biochar co-treatments that can further improve native plant establishment in contaminated soil. In a greenhouse experiment, we evaluated growth responses of two successionally-distinct native plant species, Elymus glaucus (blue wildrye) and Pseudotsuga menziesii (Douglas-fir), in contaminated mine spoils collected from the Formosa Mine Superfund Site (Riddle, Oregon, USA). Seedlings of each species were transplanted individually into pots amended with biochar, locally collected rhizosphere-soil, assumed to contain mycorrhizal fungi, a co-treatment containing biochar and rhizosphere soil, or that contained neither of these treatments (control) in a full factorial design. We hypothesized that (1) individual treatments amended with biochar and rhizosphere soil containing mycorrhizal fungi would increase plant biomass compared to un-amended controls and that (2) co-amended treatments would synergistically increase plant biomass compared to either treatment alone. In contrast to our first hypothesis, we found that the biochar treatment reduced shoot biomass and chlorophyll content of Elymus glaucus relative to unamended controls. There were no effects of biochar detected on P. menziesii, however mycorrhizal fungi and the co-treatment increased the root to shoot ratio compared to the control. We did not find evidence to support our second hypothesis of synergistic effects by the co-treatment on the growth of either plant species. Although the treatments tested in this experiment did not increase plant biomass, both native plant species were able to grow in contaminated mine spoils while maintaining mycorrhizae. This has important implications for the restoration of abandoned mines, where beneficial soil microorganisms are deficient or absent.
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Details
- Title
- Effects of biochar and mycorrhizal fungi on the survival and growth of two native plant species in contaminated mine soil
- Creators
- Austin Noah Frewert
- Contributors
- Tanya E Cheeke (Advisor) - Washington State University, Biological Sciences, School of
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Sciences, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Identifiers
- 99900896436301842
- Language
- English
- Resource Type
- Thesis