Overly acidic soils have long posed a challenge for farmers, affecting crop yields and food security. Acidic conditions in soil are often caused by industrial emissions and fertilizer use, which can limit agricultural productivity. Sub-Saharan Africa is one region that loses significant revenue each year due to poor soil conditions.
A traditional solution to this problem has been liming, the process of adding crushed limestone to soil to neutralize acidity. Historically, it was believed that while liming improved crop yields, it also increased carbon emissions.
However, new research from the Georgia Institute of Technology suggests that liming may actually help reduce atmospheric carbon dioxide while supporting agricultural output. Chris Reinhard, associate professor in the School of Earth and Atmospheric Sciences at Georgia Tech, said: “The current thinking about liming is that farmers must choose between doing something that could benefit them economically or reducing their greenhouse gas emissions. But this is often a false choice. They can do both.”
This conclusion comes from a study published in Nature Water titled “Using Carbonates for Carbon Removal.” The research introduces a framework for understanding how liming could play a role in both food security and greenhouse gas mitigation.
The team’s work includes field studies in the Upper Midwest’s Corn Belt as part of a Department of Energy project and extends to farms in southern Georgia and North Carolina with support from the Grantham Foundation. On these farms, researchers collect data on soil pH, nutrients, trace elements, and greenhouse gas fluxes. This information is then combined with machine learning models to predict how different soils respond to liming.
Reinhard explained: “Our goal is to develop a way that farmers can monitor and plan cheaply, and largely through techniques they are already using, so we don’t have to send out a whole team to gather data. We are trying to develop a predictive model architecture for planning agricultural practice across scales, but it’s important that the techniques required on the field are actually feasible for farmers.”
These findings may inform policy decisions related to farming subsidies and international aid programs aimed at improving food security. Expanding liming practices could help regions such as sub-Saharan Africa become more self-sufficient while also offering environmental benefits.
Researchers note that beyond carbon dioxide reduction, liming may lower other greenhouse gases like methane and nitrous oxide—gases associated with agriculture’s climate impact.
While liming has been used for centuries as an agricultural practice, ongoing research indicates its potential role in addressing climate change as well as boosting crop production.
