Only a fraction of conventional row crop farmers grow cover crops after harvest, but a new global analysis from the University of Illinois shows the practice can boost soil microbial abundance by 27%.
The result adds to cover crops’ reputation for nitrogen loss reduction, weed suppression, erosion control, and more. Although soil microbial abundance is less easily observed, it is a hugely important metric in estimating soil health.
“A lot of ecological services are done by the soil microbiome, including nutrient cycling. It’s really important to understand how it functions and how agriculture can form a healthier soil microbiome,” says Nakian Kim, doctoral student in the Department of Crop Sciences at the University of Illinois and lead author on a new paper in Soil Biology and Biochemistry.
Other studies have shown benefits of cover cropping on the soil microbial community, but most of them have been one-offs influenced by specific site conditions, unique seasonal effects, idiosyncratic management regimes, and the researchers’ chosen analysis methods. Kim’s work is different in that he looked for universal patterns among dozens of these one-off studies.
“Our analysis shows that across 60 field studies, there was a consistent 27% increase in microbial abundance in fields with cover crops versus no cover crops. It’s across all these studies from around the world,” says Maria Villamil, associate professor in crop sciences and co-author on the paper.