Direct Measurement of Carbon Dioxide Removal Due to Enhanced Weathering

Enhanced weathering (EW) is a durable carbon removal strategy with clear pathways to produce significant global supply on a decadal scale. Despite increasing interest and investment in this process, there have been limited direct, continuous observations of instantaneous carbon removal rates from feedstock dissolution. In this study, we monitor a soybean plot amended with basalt in Southeast Virginia using continuous in-soil CO₂ monitors, a method not previously applied in agricultural EW trials. We provide clear evidence of CO₂ flux reduction within the soil profile, equivalent to 1.04 tCO₂ ha^–1 yr^–1. This removal is most substantial in the growing season, following significant rain pulses. This work supports that direct, continuous gas-phase measurements could play an important role in advancing our understanding of biotic and abiotic influences on enhanced weathering rates while demonstrating enhanced weathering to be a rigorous, scalable method of durable carbon removal.