Climate smart grazing: The impact of adaptive multi-paddock grazing on soil carbon stocks, organic carbon stability and soil health in southern Ontario

Abstract

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 the 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.