UNIVERSITY PARK, Pa. — A nearly $1 million grant from the U.S. Department of Agriculture (USDA) awarded to Penn State’s College of Agricultural Sciences will support research on soil health and weed suppression in organic farming.

With the $999,999 award from USDA’s Organic Transitions Program, principal investigator Jason Kaye, distinguished professor of soil biogeochemistry, and colleagues will investigate methods to enhance soil health and suppress weeds within organic annual and perennial rotations.

“One of the challenges facing farmers is balancing the goals of managing weeds and improving soil health,” he said. “Tillage is a common tool for controlling weeds, especially in organic systems, yet it also disturbs the soil, degrading its long-term fertility. We aim to inform farmers about selecting perennial species and rotations that suppress weeds, build soil health and are profitable.”

To do that, the scientists will compare how single species and mixtures of perennials affect weed growth, while assessing soil physical and biological health. Another component will focus on corn yields based on two years of perennials versus two years of annual cash crops — soybeans and wheat — with cover crops.

Rotating perennial hay crops with annual cash crops also may offer an opportunity to suppress weeds and improve soil health.

“Planting perennial crops, which are cut for hay multiple times over two years or more, can interrupt weed life cycles and draw down weed seeds in the soil,” Kaye said. “The lack of disturbance under perennials allows microorganisms to build organic matter and soil fertility.”

Throughout the project, the team will have regular meetings with farmers, providing opportunities to share research results and discuss experiences with weed management, selecting perennial species and designing rotations.

The research team includes Carolyn Lowry, assistant professor of plant science, Guojie Wang, assistant professor of forage crop systems, and Kathleen Arrington, postdoctoral scholar.