In a study in the journal Geophysical Research Letters, researchers write that cover crops have “significantly” increased throughout the Midwest.

Cover crops are used in place of crops intended for sale or animal forage. Farmers most commonly use rye or winter wheat for cover. Instead of being bare and exposed to the elements and erosion, these fields resist erosion. As the crop grows and decomposes, its nutrients are absorbed by the soil. And according to the U.S. Department of Agriculture, the crops can dry out wet fields before planting and even increase future crop yields.

The researchers created an algorithm that helped identify images of cover crops by searching for bare fields that turned green during the most common cover crop growing season in April and May, then brown once the crops died and decomposed later in the year. The model used machine learning to differentiate cover crops from weed-filled fields and cash crops.

Overall, they write, the use of cover crops increased from just 1.8 percent in 2011 to 7.2 percent in 2021.

They found a direct relationship between the use of cover crops and funding promoting the practice. One such incentive, the USDA Pandemic Cover Crop Program, reduces crop insurance premiums by $5 per acre for farmers who invested in cover crops.

Now that it’s possible to detect cover crops from satellite imagery, they say, it will be easier to promote cover crop adoption.

“At the moment, cover cropping remains something for innovators and early adopters; it hasn’t taken hold as a common practice,” Jonathan Coppess, an associate professor of agricultural and consumer economics at the University of Illinois at Urbana-Champaign and a study co-author, said in a news release. “It adds cost, risk and management challenges, but important learning is happening among innovators and farmers are gaining valuable experience.”