Enhanced weathering in the US Corn Belt delivers carbon removal with agronomic benefits.

Terrestrial enhanced weathering (EW) of silicate rocks, such as crushed basalt, on farmlands is a promising scalable atmospheric carbon dioxide removal (CDR) strategy that urgently requires performance assessment with commercial farming practices. We report findings from a large-scale replicated EW field trial across a typical maize-soybean rotation on an experimental farm in the heart of the United Sates Corn Belt over 4 y (2016 to 2020). We show an average combined loss of major cations (Ca ²⁺ and Mg ²⁺ ) from crushed basalt applied each fall over 4 y (50 t ha ^-1 y ^-1 ) gave a conservative time-integrated cumulative CDR potential of 10.5 ± 3.8 t CO ₂ ha ^-1 . Maize and soybean yields increased significantly ( P < 0.05) by 12 to 16% with EW following improved soil fertility, decreased soil acidification, and upregulation of root nutrient transport genes. Yield enhancements with EW were achieved with significantly ( P < 0.05) increased key micro- and macronutrient concentrations (including potassium, magnesium, manganese, phosphorus, and zinc), thus improving or maintaining crop nutritional status. We observed no significant increase in the content of trace metals in grains of maize or soybean or soil exchangeable pools relative to controls. Our findings suggest that widespread adoption of EW across farming sectors has the potential to contribute significantly to net-zero greenhouse gas emissions goals while simultaneously improving food and soil security.
Competing Interests: Competing interests statement:D.J.B. has a minority equity stake in Future Forest/Undo, and is a member of the Advisory Board of The Carbon Community, a UK carbon removal charity, and the Scientific Advisory Council of the non-profit Carbon Technology Research Foundation. J.S.J. is funded through the public benefit corporation, Mati Carbon, a subsidiary of the not for profit Swaniti Initiative. N.J.P and C.T.R were co-founders of the CDR company Lithos Carbon, but have no remaining financial ties to the company. The remaining authors declare that they have no competing interests.