A Yale-led study found that when farmers across the Mississippi River Basin spread crushed limestone on their fields, soil stores more carbon dioxide than it emits.
Here's what to know
Researchers say liming, which farmers have long used to correct acidic soils and help crops perform better, appears to help store substantial amounts of carbon across major agricultural regions, particularly America's heartland.
According to YaleNews, the Mississippi River Basin covers about 41% of the contiguous United States and includes around 65% of U.S. croplands, where liming is already widely used.
On farms, limestone is applied as a way to manage pH while improving soil conditions and yields. Tim Jesper Suhrhoff, a geochemist at Yale and the study's first author, said, "One of the exciting things about this result is that it aligns climate action with something that is already good for farmers."
More background
As crushed limestone dissolves in wet soil, it can react with carbon dioxide and form bicarbonate ions. From there, the bicarbonate can move out through soils, groundwater, and rivers before reaching the ocean, where the carbon may remain stored for very long periods of time.
Scientists have long questioned whether limestone application might release carbon dioxide overall because the rock already contains carbon. A key part of the study was examining what would have happened without lime, which gave a clearer view of the practice's net climate effect.
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Healthier soils and stronger crop yields can help farmers remain productive, supporting a more resilient food system for communities that rely on affordable and dependable harvests.
What's being done?
Liming is a familiar farming practice that can improve field conditions while also helping reduce heat-trapping pollution.
For researchers and agricultural decision-makers, the results add support that soil pH management comes with a plethora of benefits. That may influence future discussions about climate and farm policy.
Christopher Reinhard, a professor at the Georgia Institute of Technology and co-corresponding author of the study, said, "Better soil pH management can improve yields and soil health, and our work shows that it can also be good for the climate. That gives us another reason to expand limited access to it where it is sensible."
Where can I learn more?
These stories explore other ways soils and crushed rock support farming while helping cut climate pollution.
• On cropland, rock dust can boost yields while cutting climate pollution from fertilizer use.
• Farmers could turn basalt waste into a market that improves soils and food security.
• Across carbon farming projects, soil is a climate solution when nutrients and carbon stay put.
• Around the world, soil degradation threatens food security as climate pressure weakens harvests.
• Scientists found biochar can clean soil while lowering costs for landowners facing pollution.
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