Interseeding Grass and Legume Cover Crops into Early Vegetative Stage Corn (2019 - 2021)

This project will develop best management practices for interseeding cover crops into a corn cash crop. Our objective is to evaluate the effects of interseeded cover crop species, establishment timing, and seeding method on corn productivity. This objective will help clarify treatment effects on: (1) cover crop establishment, biomass accumulation and nutrient uptake; (2) corn growth, productivity, and nutrient uptake; and (3) weed community and diversity.

A comprehensive field study will be conducted at the ISU Northwest Research and Demonstration Farm, Sutherland, IA and the Armstrong Research and Demonstration Farm, Lewis, IA. Four cover crop species will be used (winter rye, annual rye grass, cowpea, and red clover) with two establishment timings (V5 and V8) and two seeding methods (drilled or broadcast). Crop growth and development, nutrient uptake, crop reflectance, and grain yield will be evaluated. We will conduct 5 to 10 on-farm trials utilizing a sub-set of the treatments from the research farm trials that match the farmers’ interests and/or abilities. The on-farm trials will compare no interseeding with 1 or 2 additional treatments in a replicated strip trial design throughout the field. Crop growth and grain yield will be evaluated.