Compare how different cover crop species and mixtures, combined with two termination timings, affect corn and soybean performance in rotation to help refine regional recommendations for farmers and advisors.

• Cover crops improve soil and water stewardship, help suppress weeds, and retain nutrients in Illinois grain systems.
• Many species exist, but region-specific performance data is limited, especially for species mixtures and system approaches.
• Past work has focused on individual species, seeding rates, and planting dates; this project expands to species combinations and two termination timings (two weeks before planting and at planting).
• The research will refine regional recommendations and guide data-driven decisions for farmers, agronomists, and NRCS/SWCD staff.
• Generates real-world field-scale information on the positive and negative impacts of different cover crop systems on corn and soybean yields.

• Provides side-by-side comparisons of 6–8 cover crop systems for both corn and soybeans, plus a no-cover crop control.
• Evaluates yield impact, crop stand, and cover crop biomass to give farmers clear expectations for performance.
• Identifies cost‑effective species mixes and seeding rates practical for farm-scale adoption.
• Helps farmers:
  • Choose the right species or mixtures for their rotation and local conditions.
  • Plan termination timing to avoid negative effects on cash crops.
  • Strengthen management and marketing decisions with better yield predictability.
• Provides validated data that feeds into the Midwest Cover Crops Council Cover Crop Selector Tool, a widely used decision aid.

• Nathan Johanning, Extension Educator, Commercial Agriculture, University of Illinois
• Talon Becker, Extension Specialist, Commercial Agriculture, University of Illinois
• Dane Hunter, Extension Specialist, Commercial Agriculture, University of Illinois
• Luke Merritt, Research Specialist, Orr Agricultural Research and Demonstration Center, University of Illinois

• Orr Center (Baylis)
• Belleville Research Center (Belleville)
• Ewing Demonstration Center (Ewing)

Nathan Johanning
Extension Educator, Commercial Agriculture
University of Illinois Extension
618-939-3434
njohann@illinois.edu