2020
Fall-Seeded Cover Crop Tolerance to Soybean Herbicides
Contributor/Checkoff:
Category:
Sustainable Production
Keywords:
Field management Nutrient managementSoil healthTillageYield trials
Lead Principal Investigator:
Greg Endres, North Dakota State University
Co-Principal Investigators:
Michael Ostlie, North Dakota State University
Project Code:
QSSB
Contributing Organization (Checkoff):
Brief Project Summary:

Cover crop usage is expanding due to benefits including reduction in soil erosion, weed suppression, and long-term improvement in soil productivity. A risk often overlooked is herbicide residual that can greatly reduce cover crop stands. The project goal is to document the tolerance of late-summer planted, cool-season cover crops following the normally timed application of soybean pre- and post-applied herbicides that have soil residual. This research will provide information to help soybean farmers successfully establish cover crops during late summer following soybean production.

Key Benefactors:
farmers, agronomists, applicators, extension specialists

Information And Results
Project Deliverables

Final Project Results

Update:

View uploaded report Word file

Fall-seeded cover crop tolerance to soybean herbicides
Why the research is important to ND soybean farmers:
The goal of this project is to build a NDSU database on late-season planted cover crop tolerance to early season applied soybean herbicides that have soil residues. This database will aid farmers and crop advisers as plans are made for adding cover crops into their cropping system.

Research conducted:
• Carrington, 2019: ‘AG03X7’ soybean were planted May 20 followed by application of soil-applied herbicides (Pursuit, Sencor, Spartan, Valor and Zidua) on May 21 and POST herbicides (Engenia and Flexstar) on June 18. Soybean (R5-6 growth stages) were terminated by mowing on August 20. Cover crops (turnip, radish, flax, field pea, winter rye, and barley) were planted perpendicular to herbicide strips August 30 and evaluated for plant injury on September 20 and October 9.
• Fargo, 2019: Soybean were planted; soil- and foliar-herbicides applied; and cover crops were planted September 6. However, data was not generated from the trial as it was abandoned due to fall flooding.
Research findings:
• Carrington: All herbicides caused cover crop injury (biomass and/or stand reduction). Field pea was tolerant of all herbicides. Plant injury >20% occurred with radish and turnip from Sencor, and radish from Spartan and Zidua.
Benefits/Recommendations to ND soybean farmers and industry:
Research reports for the Carrington trial was written and published in ‘2019 ND Weed Control Research’ (www.ag.ndsu.edu/weeds/nd-weed-control-research). After field study is tentatively completed in 2020, a table will be published in ‘2021 ND Weed Control Guide’ as a reference for farmers and crops advisers when selecting cover crops for fall establishment following soybean. This database will aid in successful establishment of fall cover crops, which will reduce soil erosion, help manage soil moisture, increase long-term productivity of soil, plus other benefits.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.