High glucosinolate mustard (HGM) can be planted as a cover crop to suppress weeds and disease. Studies have shown a reduction in soil-borne diseases, as well as advantages in mitigating weed pressure, after planting HGM cover crops. Mustards, and many other cruciferous plants, contain glucosinolates, which are allelopathic, meaning they produce biochemicals that affect the growth and survival of other organisms. High glucosinolate mustard varieties have high levels of glucosinolates and have been shown to suppress the growth of weed seedlings, as well as helping to reduce soil-borne disease. The glucosinolates in HGM plants hydrolyze into molecules called volatile isothiocyanates, which are partially responsible for allelopathy. Little research has been done in the Northeast to quantify the effects of HGM cover crops in reducing skin disease in potatoes (Solanum tuberosum). Potato demand hinges on appearance, as consumers often refuse individual potatoes with skin defects such as common scab or rhizoctonia, and potatoes for seed are rejected if they have significant damage to skin quality. Rhizoctonia, a soil fungus, is particularly common in cool, wet growing regions like the Northeast. Reducing these skin diseases would increase the marketable yields of potato crops. High glucosinolate mustard cover crops would provide additional benefits to weed competition and soil health. Keeping the ground covered with a living cover crop for months after a regular-season cash crop is harvested helps to stabilize and build soil aggregates, as well as providing organic matter and scavenging nutrients in the soil. The integration of HGM cover crops into vegetable production could prove to be a beneficial introduction in multiple ways.
Vermont, University of Vermont
Darby, Heather; Harwood, Hannah; Cummings, Erica; and Monahan, Susan, "High Glucosinolate Mustard and Potato Trial" (2013). Northwest Crops & Soils Program. 243.