Cover crops, often planted in effort to control erosion, tie up nutrients, improve soil quality or suppress weeds, have grown in popularity recently. But understanding the crops' true value for cash crops grown on the same soil – and ecosystems around the field – has been difficult.
With new research published in the March issue of the Agricultural Systems journal, a group of agronomists, entomologists, agroecologists, horticulturists and biogeochemists from Penn State's College of Agricultural Sciences aimed to quantify the real value of cover crops.
"As society places increasing demands on agricultural land beyond food production to include ecosystem services, we needed a new way to evaluate 'success' in agriculture," said Jason Kaye, professor of biogeochemistry.
"This research presents a framework for considering a suite of ecosystem services that could be derived from agricultural land, and how cover crops affect that suite of services," he said.
Cover cropping is a popular conservation strategy in the Chesapeake Bay region, largely an effort to improve water quality.
"Our analysis shows how the effort to improve water quality with cover crops will affect other ecosystem services that we expect from agricultural land," Kaye added.
Stacking up the benefits
The research quantified the benefits offered by cover crops across 11 ecosystem services. Benefits included increased carbon and nitrogen in soils, erosion prevention, more beneficial soil fungi that help plants absorb nutrients, and weed suppression.
Related: 12 Ways to Boost Cover Crop Performance
Lead researcher Meagan Schipanski explained that commonly used measurements of ecosystem services can be misleading due to the sporadic nature and timing of some services cover crops provide.
For example, cover crops' ability to retain nutrients happens primarily during the growth stage. Weed suppression, however, occurs during growth of the cash crop. Soil carbon benefits occur slowly over decades.