Graduate Exit Seminar - Alec Ogg

Plan to join Alec Ogg's graduate exit seminar on July 10, 2025, at 9:00 am in Kottman Hall, Room 333 or via Zoom. Alec will present, "Beyond Stocks: Quantifying Management Gains and Capacity Ceilings of Soil Carbon across Land-use Systems"

Abstract: Accurate projections of soil organic carbon (SOC) sequestration require metrics that (i) disentangle management-driven gains from inherent soil variability and (ii) indicate the quantity of stable SOC storage capacity that remains. This thesis applies two complementary frameworks, root-zone SOC enrichment (Chapter 2) and mineral-capacity saturation (Chapter 3). Chapter 2 analyzes 262 pedons spanning 14 soil series in Ohio, North Carolina, and Virginia under five land uses (conventional tillage, minimum tillage, no-till, meadow, forest). The root-zone enrichment metric compares 0-30 cm SOC to a 30-60 cm baseline, isolating management effects from background heterogeneity. Chapter 3 quantifies mineral-associated organic carbon (MAOC) and chemically resistant SOC (rSOC) in three Ohio soil series managed under conventional or no-till for > 15 years. Maximum capacities were predicted with a 95th quantile model relating carbon to silt + clay content. Results will be presented during this seminar. Together, these chapters show that conservation practices can accelerate SOC accrual, including in stable pools, where mineral capacity is not yet filled, but textural and pedogenic factors influence both enrichment and saturation. Sequestration targets and carbon accounting frameworks must therefore integrate site-specific mineral limits and land-use history to yield credible mitigation strategies.

Advisor: Dr. M. Scott Demyan