Processes Involved in the Weed Suppressiveness of Hairy Vetch and Implications for Weed Management in Vegetable Production

View the project final report

• 2006 annual report

Commodities

• Agronomic: corn, hay
• Vegetables: carrots, cucurbits, onions, peppers, tomatoes

Practices

• Animal Production: feed/forage
• Crop Production: application rate management, cover crops, crop rotation
• Natural Resources/Environment: biodiversity
• Pest Management: allelopathy, weed ecology
• Soil Management: soil quality/health

With sustainable agriculture on the rise, we need to explore low cost means of addressing critical issues such as weed management. Before the advent of synthetic herbicides, several systems were used to build weed suppressive cropping systems. The use of allelopathic species “Nature’s own herbicides” is a key to improving weed management in sustainable and organic cropping systems. Legume cover crops, like hairy vetch (Vicia villosa), are gaining importance, especially in vegetable-based cropping systems, where short-term rotations are practiced, because they address three key issues: species diversity, soil quality, and weed suppression. There is a large body of studies documenting the ability of hairy vetch residue to suppress weeds in cropping systems. However, several key questions need to be addressed in order to optimize the contribution of hairy vetch to weed management. For example, (i) how much biomass of hairy vetch should be produced per unit area to achieve acceptable weed suppression? (ii) Do weed species differ in their susceptibility to hairy vetch residue? (iii) Are crop species also susceptible to these residues? If so, what it the optimal time for a grower to wait between cover crop kill and crop planting? These are questions we are looking to answer in this study and the complementary NC-SARE Grower Project we have going on with our organic grower cooperator in Clare, MI. Our goal is to quantify the weed suppressive effects of hairy vetch, determine the role of allelopathy in the weed suppressiveness, and measure the susceptibility of weed species, as well as crops, to hairy vetch extracts. We will then make recommendations, in extension publications and presentations at grower’s meetings, regarding the benefits of hairy vetch and optimum planting dates following its kill.

Project Outcomes:

This work uses hairy vetch to improve weed management and the sustainability of vegetable production systems. The expected short-term outcomes include: increased awareness of growers to the benefits of introducing cover crops (specifically hairy vetch) into their rotations and augmented appreciation of integrated weed management practices. The intermediate-term outcomes include: herbicide savings, fertilizer savings, and the potential for the development of new bioherbicides. The long-term benefits to this research could include: improved weed management, increased sustainability and yields of vegetable production systems using hairy vetch as a cover crop. The short-term and intermediate-term outcomes will be monitored via grower surveys and attendance at our presentations.

Contribution of project outcome towards NCR-SARE’s broad based outcomes:

1. This research will increase the monetary efficiency for cucumber and other vegetable growers by reducing the need for synthetic fertilizers and herbicides.

2. By increasing soil health and decreasing nutrient leaching, erosion, and the dependence on synthetic inputs, this project will aid in improving the sustainability of the environment.

3. By reducing the need for synthetic inputs, this research will improve the quality of life for farming communities.