Evaluating "Flex Ear" Corn Varieties for Agronomic and Conservation Performance

Project Overview

Project Type: Partnership
Funds awarded in 2020: $29,363.00
Projected End Date: 12/31/2022
Grant Recipient: University of Vermont Extension
Region: Northeast
State: Vermont
Project Leader:
Jeffrey Sanders
University of Vermont Extension
Dr. Heather Darby
University of Vermont Extension

Information Products


  • Agronomic: corn


  • Crop Production: intercropping

    Proposal abstract:

    Although widely adopted, barriers remain to establishing a successful interseeded cover crop. Cover crop growth can be inhibited by the inability of light to penetrate the corn canopy cover which impedes cover crop photosynthesis. Shade from the corn canopy can be reduced with lower corn populations or leaf architecture that is more vertical. Understandably, farmers are reluctant to decrease corn populations in order to promote cover crop growth out of concern about decreasing crop yield. Flex ear or indeterminate hybrids may be able to offset yield decline with higher quality while also promoting cover crop growth with more vertical leaf architecture.

    The project proposed here will provide information in identified research gaps on varietal differences in “flex” or indeterminate corn hybrids, and the impact of corn populations on both corn yield and cover crop success. In on-farm research conducted over two years using rigorous scientific methods, six corn varieties will be evaluated for yield and quality at seeding rates of 26K, 30K, and 34K. Cover crop success of interseeded cover crops will be determined by cover crop biomass after cash crop harvest. Light infiltration will be measured bi-weekly using LI-COR Sensor to determine if there is a relationship between cash crop shade and cover crop growth.  Research results of data analyzed with robust statistical methods will be presented in a technical report, factsheet, webinar, and at field days, workshops, and conferences. Over 500 stakeholders will be reached through materials presented online, in print, and in-person.

    Project objectives from proposal:

    Broad Objective. This project seeks to support farmers in building sustainable cropping systems while maintaining yields and economic viability.

    Objective 1. Identify corn varieties and seeding rates that meet cash crop yield and cover crop biomass goals.

    Objective 2. To identify indeterminate corn varieties suitable for Northeast production.

    Objective 3. Determine the profitability of the cropping system, calculating the cost of corn seed, cover crop seed, corn yield, cover crop termination (if applicable), and purchased feed (to offset lost corn yield). This information can be used to choose varieties that meet the farmer’s conservation and profitability goals.

    Objective 4. Create outreach with farmer-friendly technical reports, factsheets, webinars, and via presentations at field days and the Northeast Cover Crop Council Conference. Over 200 farmers, agribusiness personnel, technical service providers, and other stakeholders will be reached.


    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.