2015
Integrating a rye cover crop as an additional tool to manage glyphosate-resistant Palmer amaranth
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Contributor/Checkoff:
Michigan Soybean Promotion Committee
Category:
Sustainable Production
Keywords:
AgricultureCrop protectionHerbicide
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Christy Sprague, Michigan State University
Co-Principal Investigators:
Project Code:
1509
Contributing Organization (Checkoff):
Michigan Soybean Promotion Committee
(n/a)
Institution Funded:
Michigan State University
(n/a)
Brief Project Summary:

Glyphosate-resistant Palmer amaranth continues to be a threat to Michigan soybean producers. From past funding and partnerships with MSPC, we have been able to research and develop our current best recommendations for management of this weed. However, even though we have made great progress in developing Palmer amaranth management strategies, there is still a lot more work that needs to be done to refine and develop additional management strategies that may prove to be more successful. One option that may be useful to improve management of glyphosate-resistant Palmer amaranth is to incorporate the use of cover crops into an overall management strategy. With this in mind, we initiated a project...

Unique Keywords:
#weed control
Information And Results
Final Project Results

Results (Year 1):
• Cereal rye produced 120 g m-2 of dry biomass at the time of cover crop termination.
• At cover crop termination, weed biomass was 77% lower in the cereal rye plots compared with the no cover controls.
• Cereal rye was not effectively controlled by mowing and produced another 128 g m-2 of dry biomass by the following week and was then terminated with glyphosate.
• Soil moisture at the time of planting was not influenced by the rye cover crop or cover crop termination method at a 3 or 4.7-inch soil depth.
• Palmer amaranth emergence started on June 16th and continued to emerge well into August, with peak emergence around June 24th.
• Adequate precipitation after Valor was applied PRE resulted in good control of Palmer amaranth in the low and high management systems.
• POST Liberty applications effectively controlled emerged Palmer amaranth; however, the optimal treatments that also contained Warrant are providing longer control in some instances.
• Canopy closure was greater for 7.5-inch rows from July 15th through Sept. 1st, with over 90% canopy cover occurring on July 28 for 7.5-inch rows and August 13th for 30-inch rows. Soybean canopy cover was not affected by the rye cover crop or cover crop termination method.
• The greater canopy cover in the 7.5-inch rows reduced the number of new emerged Palmer amaranth plants in the low and high management systems by 52% compared with the 30-inch rows. Later season Palmer amaranth emergence as not affected by cover crop.
• In the no management plots, end of the season biomass was not affected by cover crop or row width.
• There were herbicide system by row width and herbicide system by cover crop interactions for soybean yield. Soybean yields were highest in the high management systems in narrow rows (57.6 bu A-1) and with no covers (59.5 bu A-1). Significant reductions in yield occurred in the no management plots and for the low management plots in 7.5-inch rows.

2016 Meetings and Research:
We are proposing to repeat this research in 2016. Cereal rye was planted on September 30, 2015 in preparation for the 2016 research season. Preliminary results have and will continue to be presented Michigan soybean growers. This project is being supported by MSPC and Project GREEEN.

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.