Researchers Find New Carbon-Capture Potential

Friday, September 8, 2023

A five-year study at the University of Illinois Energy Farm found applying ground-up silicate rock to Midwestern farm fields can capture significant amounts of carbon dioxide and prevent it from accumulating in the atmosphere.

Working with Eion Corp., researchers at the University of Illinois Urbana-Champaign and the Leverhulme Centre for Climate Change Mitigation (LC3M) developed a new method to calculate the CO2-reduction potential of basalt rock amendments applied to cropland soil, a process known as enhanced weathering.

Researcher Evan DeLucia, who is director emeritus for the Institute for Sustainability, Energy and Environment (iSEE), as well as U of I professor emeritus of plant biology and co-investigator for the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI) at Illinois, partnered with researcher Ilsa Kantola, who is a research scientist at iSEE and the Carl R. Woese Institute for Genomic Biology to study how enhanced weathering could potentially be used as a carbon-capture tool.

The research team was able to successfully quantify the carbon-capture potential by calculating both the weathering rate and CO2-reduction potential of the basalt rock when applied to maize and miscanthus fields, components that are critical to optimizing carbon sequestration efforts.

The researcher’s calculations showed that enhanced weathering reduced net carbon loss to the atmosphere by 42% in maize plots. Paired with conservation tillage or cover crops, the basalt application could turn maize into a net carbon sink.

In miscanthus plots, which already stored more CO2 than they emitted before the addition of basalt, enhanced weathering more than doubled carbon storage. The finding adds to the potential climate benefits of this renewable bioenergy crop, one of three targeted by CABBI in its U.S. Department of Energy-funded work.

“In addition to reducing emissions, we desperately need effective ways to draw down atmospheric carbon dioxide. Our results suggest that basalt application to farms could be a win-win for farmers and for the planet, improving yields and drawing down CO2,” said DeLucia.

With enhanced weathering, silicate rock is applied to farmland to capture carbon before it reaches the atmosphere. As the rock weathers, calcium and magnesium are released and react with dissolved CO2 to produce bicarbonate, essentially locking up the gas and redirecting it into groundwater.

The Illinois team repeatedly applied finely-ground basalt on twin fields at the Energy Farm for four years — one field with a maize-soybean crop rotation and the other with Miscanthus x giganteus, a perennial grass that is emerging as a productive bioenergy crop to replace fossil fuels.