Customizing Ecosystem Services

Problem

Why do cover crop mixes produce profoundly different results depending on when and where they are planted?

• Cover crop mixtures comprised of multiple species planted in rotation between cash crops provide a suite of benefits—such as erosion reduction, weed control, addition of carbon and nitrogen to the soil, and support of beneficial organisms.

Findings

Researchers worked with eight participating farmers to compare a standard five-species cover crop mix to a "farm-tuned" mixture of the same species with seeding rates adjusted to achieve farmer-desired services.

• They found that growing degree days and nitrogen affected how the mixtures grew, countering a prevailing assumption that seeding rates had the biggest impact on ecosystem services.
• Their results showed that when soil inorganic nitrogen availability is high at the time of cover crop planting, highly competitive species can dominate mixtures, which could potentially decrease services provided by other species, especially legumes.

Impact

The knowledge gained from this study—novel due to its breadth and complexity—will be used to design custom seed mixes with predictable growth from the different species.

• Recommendations from the study can help farmers choose cover crop species and seeding rates according to their inorganic nitrogen in soil and planting dates to ensure the provision of desired ecosystem services.

Research Credit

Team

• Barbara Baraibar, Ebony Murrell, Brosi Bradley, Mary Barbercheck, David Mortensen, Jason Kaye, Charles White

Participating Departments

• Ecosystem Science and Management
• Entomology
• Plant Science

Partners

• Penn State Russell E. Larson Agricultural Research Center
• Eight organic commercial dairy farmers in Pennsylvania and New York

Competitive Funding

• USDA NIFA (OREI)
• Organic Farming Research Foundation
• USDA NIFA (Organic Transitions)
• College of Agricultural Sciences (Strategic Networks and Initiatives Program)

Federal and State Appropriations

• USDA NIFA Hatch Projects PEN04571, PEN04606, and PEN04600, Accession #1003346, # 1009990, and #1009362

Emerging Discoveries

Cover crop mixtures must be 'farm-tuned' to provide maximum ecosystem services

August 17, 2020

Penn State researchers, in a recent study, were surprised to learn that they could take the exact same number of seeds from the same plants, put them in agricultural fields across the Mid-Atlantic region and get profoundly different stands of cover crops a few months later.

Published Research

Cover crop mixture expression is influenced by nitrogen availability and growing degree days

• Baraibar B, Murrell EG, Bradley BA, Barbercheck ME, Mortensen DA, Kaye JP, et al. (2020) Cover crop mixture expression is influenced by nitrogen availability and growing degree days. PLoS ONE 15(7): e0235868. https://doi.org/10.1371/journal.pone.0235868