Soil Organic Carbon Dynamics and the Effects of Resident Vegetation in Pelee Island Soils

Colton Geil, The University of Western Ontario

Abstract

Soil organic carbon (SOC) enhances nutrient retention, structural stability, porosity, aeration, water infiltration, and overall soil health. Understanding SOC turnover and its preservation in soils is paramount to managing carbon sequestration. On Pelee Island, we used δ¹³C, δ¹⁵N and C/N of SOC at various depths to identify the sources and evolution of SOC with time. At depths >150 cm, SOM was from a mixture of aquatic and terrestrially derived sources. We also analyzed the impact of permanent cover crops called ‘resident vegetation’ on the ability of soils to store carbon in different aggregate size fractions. SOC increased with increasing duration of resident vegetation in each aggregate fraction. Under prolonged resident vegetation we found a greater proportion of new carbon stored in the smallest and most resilient aggregate fraction (mm). These results are significant for measuring carbon capture at the Pelee Island winery, necessary for obtaining agricultural carbon credits.