Alternative cover crop management strategies for vegetable crop rotations

The Central Sands area of Wisconsin is home to one of the largest irrigated vegetable production areas in the United States. Producers utilize cereal rye as a cover crop for erosion control, but have not expanded on opportunities that cover crops may have for nutrient management, rotational benefits, disease management, and weed suppression. Reluctance to cover crops in the vegetable rotation is primarily due to the lack of management guidelines and practices. Experiments were conducted from 2005 to 2008 to develop management options for perennial and annual cover crops included in a continuous vegetable rotation. Perennial cover crop studies focused on common forage species that were interseeded with snap bean and maintained through a snap bean to sweet corn progression. The studies determined the proper stage of snap bean development to interseed perennial cover crops to maintain snap bean yield and a high level of cover crop persistence for sequential seasons. Annual cover crop studies focused on the potential for spring planted annual species to provide nitrogen to a subsequent snap bean crop after green manure incorporation. The studies also attempted to find herbicide or tillage management that would minimize cover crop residue in a subsequent snap bean crop and reduce any quality problems that residue would cause in the harvested snap bean. This research showed that perennial cover crops could serve as an alternate source for nitrogen when interseeded with vegetable crops, and would persist for up to two years after establishment. Spring planted annual cover crops did not provide yield or quality benefits to subsequent snap beans following green manure incorporation of the biomass. A glyphosate application followed by tillage was the most effective method at limiting cover crop residue interference in a subsequent snap bean crop. The management practices developed in this research showed that cover crops can be successful in a continuous vegetable rotation.