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Thesis Defence: Consequences of Elemental Sulfur Induced Soil Acidification on Bacterial and Fungal Communities in Southern Okanagan Vineyard Soil
February 12 at 3:00 pm - 7:00 pm
Diego Yusta Belsham, supervised by Dr. Miranda Hart, will defend their thesis titled “Consequences of Elemental Sulfur Induced Soil Acidification on Bacterial and Fungal Communities in Southern Okanagan Vineyard Soil” in partial fulfillment of the requirements for the degree of Master of Science in Biology.
An abstract for Diego Yusta Belsham’s thesis is included below.
Defences are open to all members of the campus community as well as the general public. Please email miranda.hart@ubc.ca to receive the Zoom link for this defence.
Abstract
Elemental Sulphur (So) can be used as a fertilizer, acidifier or biocide in agricultural ecosystems. So changes soil pH and results in the production of metabolites toxic to many microbes. Bacteria and fungi have differential susceptibility to So which may lead to changes in soil microbial communities and functioning. Recent insights into the importance of microbes in soil and ecosystem health warrants a better characterization of soil microbial communities’ response to So. This study assessed the sensitivity of fungi and bacteria to So amended alkaline soil in an arid region of a commercial vineyard in the southern Okanagan valley of British Columbia (BC). Using bacterial and fungal isolates collected on site, I tested their tolerance to both So and concomitant changes to pH. In addition, I measured changes to soil bacterial and fungal communities following the addition of ~3000 kg of So to acidify ~2 ha of soil. Finally, I assessed microbial decomposition and above ground plant diversity following So application for functional analysis. I found that, while there is potential for So and pH to impact microbial growth in my growth assays, So application did not significantly change microbial or plant community structure, and I observed no changes to organic matter decomposition in my system. Notably, So application did not lower the pH of soil in my system, likely due to buffers present in the irrigation water. Other external factors such as So particle size may have also impacted the timescale of So oxidation in soil. Growers should consider these factors when using So as an acidifier, fertilizer or biocide.
