Researchers Confirm Common Soil Treatment Can Improve Farm Crop Yields and Remove Carbon

For centuries, farmers have relied on simple minerals to balance soil pH and grow stronger crops. Only recently have scientists realized that this practice, known as liming, may in many cases remove more carbon dioxide than it releases. But proving that requires tracking carbon far beyond the field itself.

In a landmark study published in Nature, 11 researchers tracked the impacts on the carbon cycle across the Mississippi watershed and its 11 states after almost a century of liming. The results show that while liming can initially release carbon, it becomes a carbon sink after a few decades, effectively removing the greenhouse gas from the atmosphere.

“Farmers have been doing enhanced weathering in U.S. agriculture for a little over a half century,” said Chris Reinhard, an associate professor in the School of Earth and Atmospheric Sciences and an author on the paper. “This is a giant natural experiment that's been going on for decades that allows us to figure out how much carbon makes it all the way through the watershed system."

The study grew out of a U.S. Department of Energy Earthshot Initiative grant focused on understanding the role agricultural liming could play in long-term carbon removal.

Tracking Carbon

When limestone or other carbonate minerals are added to soil, the effects don't stop at the field's edge. The minerals’ reaction with the ground’s acidity results in chemical products that move through rivers and eventually reach the ocean. While carbon-related changes can be measured in the field, tracing them across an entire watershed is far more difficult.

But data from decades of agricultural lime applications, fertilizer usage numbers, and river alkalinity measurements at the mouth of the Mississippi helped researchers piece together the larger picture. By analyzing more than a century of agricultural and river records, the team found that liming in the Mississippi River Basin has acted as a net carbon sink.

The findings also challenge how liming's climate impacts are typically measured. Current carbon accounting often treats lime application itself as a source of emissions. But the researchers say this approach misses an important part of the picture: Fertilizers can make soils more acidic over time, creating the need for liming. When the team accounted for both processes, they found that liming removed carbon in the long term, but fertilizer causes acidity and drives emissions. 

Modeling a Better Future

Reinhard and colleagues also created a model that captures the physics and chemistry of agricultural soils. The model can determine liming’s theoretical carbon-removal potential, testing its predictions against the historical data. In this case, about 90% of the carbon-removal benefit predicted from the model ultimately appeared in the records of river chemistry from the Mississippi River Basin. 

“The long-term goal for the model is to develop a way for farmers to plan and be able to answer questions like, ‘How do I stagger the application of lime so I'm helping the crops while also emitting as little carbon as possible?’” Reinhard said.

Beyond its climate implications, liming could help strengthen the long-term resilience of the agricultural industry. The findings suggest that managing soil pH can improve soil health and crop yields, while simultaneously reducing net greenhouse gas emissions. If managed well, one of agriculture's oldest soil management practices may offer a rare double benefit: helping farmers grow healthier crops while reducing the industry's climate footprint.

CITATION : Suhrhoff, T.J., Reinhard, C.T., Kanzaki, Y. et al. Agricultural liming is a carbon sink in the Mississippi River Basin. Nature (2026). https://doi.org/10.1038/s41586-026-11040-2