MSc Final Oral Examination: Jessica Mehre
Overview:
Interested Members of the University Community are invited to attend the Final Oral Examination for the Degree of Master of Science of Jessica Mehre of the Department of Plant Agriculture
Date: Wednesday, March 22, 2023
Time: 10:30 AM
Location: Room 307, Crop Science Building
Zoom link for remote participants: https://zoom.us/j/97705529424?pwd=aVNGOGhHSFpzbHJLdlJzSU82YkFkQT09
Meeting ID: 977 0552 9424
Passcode: 325533
Thesis Title: Climate smart grazing: The impact of adaptive multi-paddock grazing on soil carbon stocks & stability and soil health in southern Ontario
Advisory Committee
Dr. Kimberley Schneider, Advisor
Dr. Claudia Wagner-Riddle Co-advisor
Dr. Adam Gillespie
Dr. Josh Nasielski
Examination Committee
Dr. John Sulik, Chair
Dr. Kimberley Schneider
Dr. Adam Gillespie
Dr. Paul Voroney
Adaptive multi-paddock (AMP) grazing has been purported as a ‘climate-smart’ practice due to its potential to mitigate greenhouse gas emissions by increasing soil organic carbon (SOC) stocks, although contrasting results have been observed. The goal of this study was to compare SOC stocks between neighboring AMP and non-AMP beef farms in southern Ontario while simultaneously evaluating the stability and origin of potential SOC stock differences. Higher SOC and total nitrogen stocks were found in AMP, along with higher mineral-associated carbon stocks in the top 15 cm under AMP, indicating greater SOC stability with this grazing strategy. Abundances of microbial phospholipid fatty acids (PLFA) classes via gas chromatography were significantly higher in AMP than non-AMP with no change in community structure or community ratios. No differences were detected in autoclaved citrate-extractable protein, a novel soil health test. This research shows that in southern Ontario and other temperate pastures, AMP grazing should be encouraged over continuous grazing to increase SOC stocks and stability.