Buckwheat Cover Crops on Wisconsin Vegetable Farms: Grower Perspective, Genetic Variation, and a Weed Supression Study Using Tartary Buckwheat

Buckwheat Cover Crops on Wisconsin Vegetable Farms: Grower Perspective, Genetic Variation, and a Weed Supression Study Using Tartary Buckwheat

Summary

Common buckwheat (Fagopyrum esculentum) is a widely used summer cover crop on Wisconsin fresh market vegetable farms. Buckwheat cover crops are believed to provide environmental and farm production benefits including improving soil quality and fertility, weed suppression, beneficial insect habitat, and erosion prevention. Despite its utility, the relative importance to growers of different functions of buckwheat cover crops is not well understood. We use a web-based survey instrument and interviews to identify common grower practices and questions. Survey results are shared with all participants. Farmer input is used to design a series of on-farm and on-station studies on buckwheat cover crops, including a weed suppression study, a comparison of reduced-tillage killing methods, and a late-summer planted, overwintered residue study. The weed suppression experiment includes a novel comparison with a cultivated relative of common buckwheat, tartary buckwheat, which has been shown to contain possibly allelopathic substances. This project provides farmers with information about their peers’ practices, and promotes discussion and better management for buckwheat and other cover crops. It also details a novel management technique for this unique green manure.

Objectives/Performance Targets

Through this study, we plan to:

1. Conduct a survey on buckwheat cover cropping and disseminate the results to participants, which will allow them to compare their own practices to those of other growers.
2. Compare cover-cropping qualities of common buckwheat to a related species, tartary buckwheat, which shows promise in cold hardiness and allelopathy.
3. Compare reduced-tillage management techniques for killing a buckwheat cover crop, and evaluate the ability of a buckwheat mulch layer to suppress mid-summer weeds.
4. Characterize weed growth and emergence in an early summer buckwheat cover crop in order to better understand the mechanisms by which buckwheat suppresses weeds.

Accomplishments/Milestones

1. Completed the web-based survey and disseminated results to farmers. Used the survey and subsequent farmer interviews to develop field experiments.
2. The survey revealed farmers value multiple ecosystem services provided by buckwheat cover crops, including insectary, soil conservation, weed suppression, and aesthetic services.
3. Conducted field experiments on-station at two locations, Arlington and West Madison.
4. Conducted an on-farm experiment in collaboration with the farmer comparing common and tartaty buckwheat with oats in a late-planted overwintering study.

Impacts and Contributions/Outcomes

1. After taking the survey, some farmers reported a greater interest in and willingness to plant buckwheat cover crops.
2. Because of poor performance in our experiment, we do not expect WI farmers to adopt usage of tartary buckwheat cover crops, but our work has increased interest and knowledge about cover crops in general and buckwheat in particular.

• plots at Arlington
• rolling the cover crop – Arlington
• cabbage test crop
• winterkilled study – West Madison
• cover crop and weed emergence
• mowing cover crop – Arlington

Collaborators: