COMPARING SOIL HEALTH AND WEED SUPPRESSION WITHIN ORGANIC ANNUAL AND PERENNIAL ROTATIONS

One of the challenges facing farmers is how to balance the goals of managing weeds and improving soil health. Tillage is a common tool for controlling weeds, especially in organic systems, yet it also disturbs the soil, degrading its long-term fertility. Rotating perennial hay crops with annual cash crops 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. The lack of disturbance under perennials provides an opportunity for microorganisms to build organic matter and soil fertility.A key question that we aim to answer through this research is whether combining multiple species of perennials in a field improves weed suppression and soil health. We will compare single species and mixtures of perennials (up to six species) in terms of weed growth and several metrics to assess soil physical and biological health. Also, we will compare two rotations in terms of their corn yields and profitability: corn preceded by two years of perennials versus corn preceded by two years of annual cash crops (soybeans and wheat) with cover crops.Throughout the project, we will have regular meetings with farmers, providing opportunities to share research results and discuss experiences with weed management, selecting perennial species and designing rotations. Our goal is to provide farmers with information about a variety of perennials and their impacts on soil health and weed suppression. Outreach events and materials developed through this project will guide farmers in selecting perennial species and rotations that suppress weeds, build soil health, and also are profitable.