Buckwheat Cover Crops On Wisconsin Vegetable Farms: A Grower Survey and Series of Experiments.

Common buckwheat (Fagopyrum esculentum) is a widely used summer cover crop on Wisconsin vegetable farms.  Buckwheat cover crops provide a variety of production benefits and agroecosystem services, including improved soil quality, weed suppression, beneficial insect attraction, and erosion prevention. Despite its utility, farmers' perspectives on the benefits and tradeoffs of growing buckwheat cover crops are not well understood.  We implemented a web-based survey instrument and conducted grower interviews to identify common practices and concerns.  Farmer input was used to design a series of experiments on buckwheat cover crops, including a weed suppression study,  a comparison of reduced-tillage killing methods, and a late-planted, overwintered residue study.  Experiments included a novel comparison with a cold-tolerant, possibly allopathic relative of common buckwheat, tartary buckwheat (F. tataricum).  The survey indicated that farmers grow buckwheat cover crops for a variety of reasons, and associate the practice with improved overall ecosystem health.  Experiments did not show a benefit to planting tartary buckwheat over common buckwheat.  Both buckwheats reduced weed biomass in the standing cover crop compared with a fallow check, but had no effects on yield of a subsequent cabbage crop.  Reduced-tillage management of buckwheat cover crops was unsuccessful.  Oats outperformed both buckwheats in the late-planted study.