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Home > Protecting Our Lands & Waters > Clean Water Fund > Clean Water Research Program > Cover Crop Establishment

Water quality enhancements in corn cropping systems through optimization of cover crop establishment technologies

Principal Investigator: M. Scott Wells 
Organization: University of Minnesota, Department of Agronomy and Plant Genetics
Sponsor: Clean Water Fund
Award Amount: $243,910
Start Date: 4/29/2014 | End Date: 6/30/2017
Project Manager: Heidi Peterson

Publication: View in ACSESS Digital Library "Establishment and Function of Cover Crops Interseeded into Corn"   January 2018

Research ObjectivesCover crop interseeded in a corn field

  1. Evaluate cover crop establishment methods and cover crop species/mixture in a corn-based cropping system using three establishment techniques: 1 and 2) direct broadcast via highboy seeder with and without soil disturbance; and 3) interseeder drill.
  2. Assess potential groundwater quality improvements resulting from cover cropping using a calibrated Nitrogen Loss and Environmental Assessment Package (NLEAP) model and estimate soil reductions using Revised Universal Soil Loss Equation (RUSLE).
  3. Contribute to an educational program to share research findings and demonstrate cover crop establishment technologies to farmers and agricultural professionals.


Due to a short fall season in Minnesota, establishing cover crops in corn-based cropping systems is a challenge. Most Minnesota farmers harvest corn in mid-October, but best management practices (BMPs) recommend planting cover crops six-to-eight weeks prior to a killing frost, well before corn harvest. Aerial seeding between August and mid-September has mixed results due to soil moisture, improper seed placement and vulnerability to animal/insect predation. More research is needed to improve cover crop establishment in corn-based cover cropping systems.

Project Description

For this project, researchers will establish cover crops when corn is at the V7 to V8 growth stage (approximately 38 inches tall, 30-40 days after planting). At that point there is good soil moisture and also cover crops remain in a vegetative stage throughout the growing season and have a higher likelihood of surviving winter. Applying cover crop seed much before the V7 to V8 stage can lead to increased cover crop competition with the corn.

Growth stages 1-11 in a corn plant
Image from Purdue University

New Equipment and Technology

Broadcasting cover crop seeds (applying them on top of the soil surface) into corn is the simplest seeding method. However, broadcast seeding often produces inconsistent results. Without soil disturbance to incorporate the seed and achieve adequate seed-to-soil contact, cover crop establishment can be low if rainfall does not occur soon after seeding.

New technologies have been developed to allow for earlier planting and to capitalize on the benefits of broadcast inter-seeding. For example farmers have modified high-boy seeders to be capable of planting directly into growing corn.

The need for improved cover crop establishment has prompted other technologies and research. Pennsylvania State University developed a 3-in-1 inter-seeder capable of direct-drilling cover crop seed in corn as late as the V8 stage, while simultaneously applying fertilizers and herbicides. Combining field activity is cost effective. Also, applying nitrogen during the growing season can reduce the potential for nitrogen losses. 

Methods and Data Collection


Education and Outreach

Research results will target agricultural professionals, farmers, state agencies and environmental groups to include:

  • A series of crop-specific field days, winter workshops and grower meetings
  • Articles in leading agricultural magazines and newspapers
  • University of Minnesota-Extension articles distributed to the > 1,500 subscribers of Minnesota Crop News blog
  • A University of Minnesota-Extension fact sheet

Events will include:

  • Four University of Minnesota-Extension web bulletins and research updates
  • Four field day demonstrations (including the Southern Research and Outreach Summer Crops Field Day)
  • Four University of Minnesota-Extension workshops
  • Two eLeaming webinars
  • Six media interviews (or more)

Education and outreach topics will focus on: Cover crop inter-seeding technologies and subsequent impacts on water quality; explanation of best management practices; agronomic and environmental risk assessments for various management practices; economic projections for cover crop inter-seeding technologies into current com cropping systems.  

MDA Contact

Margaret Wagner
 Supervisor, Clean Water Technical Assistance Unit