A new peer-reviewed study from Cornell University challenges a popular assumption: that soil carbon-sequestering practices like planting cover crops and reducing tillage will automatically boost crop yields. In many cases, they don’t.
Instead, the global computer modeling study — published May 19 in Nature Climate Change — shows that most regenerative practices aimed at building soil organic carbon help either mitigate greenhouse gases or improve yields, but rarely both.
“For the first time, we can have contextualized information about how farmers can choose the optimal mix of practices that meet their needs to maintain crop yields while also providing climate change mitigation,” said Dominic Woolf, senior research associate in Cornell’s School of Integrative Plant Science and principal investigator of the study.
The analysis ran scenarios through 2100 using four practices: grass cover crops, legume cover crops, no-till, and leaving crop residues in fields. The results?
- Grass cover crops with no-till: Most effective for limiting greenhouse gas emissions, but worst for yield.
- Legume cover crops with no-till: Higher yields, but nearly 70% less effective at reducing emissions.
- Drier regions: More likely to suffer yield losses as cover crops compete for limited water.
- Some areas: Saw increased greenhouse gas emissions compared to conventional farming due to elevated soil nitrous oxide—273 times more potent than CO₂.
“We found a strong synergy in many locations between cover cropping and conducting no-till,” said Shelby McClelland, first author of the paper and postdoctoral researcher at NYU. “In many cases, that allows you to increase soil organic carbon much faster than individual practices alone.”
Still, the tradeoffs are steep. The team found that to maintain crop yields needed for global food security, the maximum achievable greenhouse gas mitigation would drop by about 85% compared to an approach focused solely on emissions reduction.
The study was conducted in partnership with researchers from The Nature Conservancy, the Environmental Defense Fund, Colorado State University and the Woodwell Climate Research Center. Funding came from a broad coalition including the National Institute of Food and Agriculture, U.S. Forest Service, the EPA, Bezos Earth Fund, King Philanthropies and others.
