UNIVERSITY PARK, Pa. — With a new $650,000 grant from the U.S. Department of Agriculture, Carolyn Lowry, a plant scientist in Penn State’s College of Agricultural Sciences, will lead a research team designing cover crop mixtures that are more effective at providing an array of ecosystem services.
Cover crops — grasses, legumes and forbs — are planted to cover the soil rather than for the purpose of being harvested. Cover crops help to manage soil erosion, soil fertility, soil quality, water, weeds, pests, diseases and biodiversity in an agroecosystem.
The four-year award, from USDA’s National Institute of Food and Agriculture, is focused on experiments aimed at maximizing mixture multifunctionality — or “farm-tuning” cover crop mixtures, as Penn State researchers call it — to improve ecosystem functions and resilience. The study will be conducted at Penn State’s Russell E. Larson Agricultural Research Center.
“The goal of our research is to design cover crop mixtures that are more effective at providing an array of ecosystem services,” said Lowry, assistant professor in the Department of Plant Science. “Currently, our ability to design better performing cover crop mixtures is limited by the lack of understanding of how much of each species we need in a mixture to provide a certain level of each ecosystem service we hope to obtain.”
To address these knowledge gaps, researchers will evaluate how the initial seeding rates of three cover crop species interact with environmental conditions to determine the final mixture composition. They will use a new method developed by Penn State ecology program doctoral degree candidate Emma Rice, in which she uses molecular analysis to estimate the composition of plant species in the root biomass of mixtures. This method will prove extremely valuable, Lowery explained, because unlike the aboveground portion of plants, roots are nearly impossible to attribute to species.
The researchers also plan to assess the cover crop mixture seeding rate that optimizes individual ecosystem service functions, as well as overall multifunctionality.
Finally, they will evaluate how variation in both weather and management affect cover crop mixture composition and the associated ecosystem services provided by cover crop monocultures and mixtures across 16 years of Penn State’s cover crop cocktails experiments at the Larson center. That site and those experiments have been overseen by research team member Jason Kaye, distinguished professor of soil biogeochemistry, and his research group.
“Our ability to design better performing cover crop mixtures is limited by a lack of understanding of how species composition interacts with environmental variability and management,” Lowry said. “Results from this research will aid farmers in designing cover crop mixtures that are farm-tuned to their desired ecosystem functions, farming operations and climate.”
Frances Buderman, assistant professor of quantitative wildlife ecology, also is on the research team.