Interseeding to improve winter cover crop establishment and efficiency in processed vegetable production in the Willamette Valley

• 2016 annual report

Cover crop establishment following processed vegetable culture in Western Oregon is a challenge because harvest often occurs late into the fall. Soil may already be saturated from fall rains, and the combination of wet soil and crop residue on the soil surface often prevents cover crop establishment. One option to address these challenges is to interseed the cover crop mid-season into the vegetable crop. The goal of this project is to simply compare interseeding with traditional planting of cover crops. Cover crops have been interseeded with the assistance of cooperating producers on more than 80 acres of processed vegetable crops of sweet corn and processing squash over the three years of the project in both conventional and organic systems, and performance of experimental plots compared to direct-seeded, conventionally planted, or fly-on cover crops. Field days have highlighted successes and limitations of interseeding strategies, and provided the context to develop future field tests.

1. Demonstrate the capability of interseeding with a high-clearance direct-seed planter to improve cover crop establishment and growth compared to conventional tillage or direct-seeding of cover crops after vegetable crops are harvested.
2. Determine the appropriate species and optimum time to interseed cover crops chosen by each farm cooperator so that cover crop biomass is maximized yet the cover crop does not reduce vegetable crop yield.