2019
Fall-Seeded Cover Crop Tolerance to Herbicides
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Contributor/Checkoff:
North Dakota Soybean Council
Category:
Sustainable Production
Keywords:
Field management Nutrient managementSoil healthTillageYield trials
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Greg Endres, North Dakota State University
Co-Principal Investigators:
Project Code:
QSSB
Contributing Organization (Checkoff):
North Dakota Soybean Council
$14,700
Institution Funded:
North Dakota State University, Carrington Research Extension Center
$14,700
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

If farmers are including cover crops in their farm management plans, the data generated from this study will aid in increasing their success with establishing cover crops following soybean production. The information gained from the data will aid farmers in correctly selecting cover crop species after herbicide application in soybean. Extra costs of replacement seed and replanting will be avoided by proper cover crop selection. For example, study costs would be justified by avoiding 600 acres of cover crops that were not successfully established due to incorrectly selected herbicide-susceptible species at planting costs of $25/acre.

Final Project Results

Update:

View uploaded report Word file

Research conducted:
• Fargo, 2018: Soybean were planted May 24 followed by application of soil-applied herbicides (Raptor, Sencor, Spartan, Valor and Zidua) on May 25 and POST herbicides (Engenia, Flexstar and Raptor) on June 30 at labeled rates for soybean. Cover crops (turnip, lentil, radish, flax, field pea, winter rye, and barley) were planted perpendicular to herbicide strips August 22 and evaluated for plant tolerance on September 12 and 26.
• Carrington, 2018: Soybean were planted May 16 followed by application of soil-applied herbicides (Pursuit, Sencor, Spartan, Valor and Zidua) on May 28 and POST herbicides (Engenia and Flexstar) on June 7. Soybean (R5 growth stage) were terminated by mowing on August 8. Cover crops (turnip, radish, flax, field pea, winter rye, and barley) were planted perpendicular to herbicide strips September 24 and evaluated for plant tolerance (barley, rye, and field pea) on November 2.

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 findings:
• Fargo: Cover crop injury (biomass and/or stand) was present among all crops except field pea during evaluation on September 12. Plant injury occurred with Raptor, Sencor, Spartan and Raptor (PRE and POST applied). Injury at 24-52% was noted on lentil, radish, and turnip with sulfentrazone, and 21-54% injury on flax, radish, and turnip with PRE Raptor. During September 26 evaluation, lentil, radish, and turnip had 40-57% injury with Spartan; flax, radish, and turnip had 60-79% injury with PRE Raptor.
• Carrington: Barley injury was 2-3% with Pursuit, Valor and Zidua on November 2.
Benefits/Recommendations to ND soybean farmers and industry:
Research reports for the two trials were written and published in ‘2018 ND Weed Control Research’ (www.ag.ndsu.edu/weeds/nd-weed-control-research). After field study is tentatively completed in 2019, a table will be published in ‘2020 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.