2019
Weed control strategies for non-GMO soybean growers
Contributor/Checkoff:
Category:
Sustainable Production
Keywords:
AgricultureCrop protectionHerbicide
Lead Principal Investigator:
Christy Sprague, Michigan State University
Co-Principal Investigators:
Project Code:
1914
Contributing Organization (Checkoff):
Institution Funded:
Brief Project Summary:

As profit margins tighten, growing non-GMO soybeans is good source of revenue for many Michigan farmers. Premiums for non-GMO and other specialty non-transgenic soybeans often exceed $1.00 per bushel, and are currently close to $1.50. However, one of the greatest impediments to farmers of non-GMO soybean is good weed control. Starting with a clean seed bed, including good soil-applied residual herbicides in the weed control program, making timely postemergence herbicide applications, and understanding that there are several weeds that have evolved resistance to different herbicides are all key principles that need to be incorporated into an effective non-GMO soybean weed control program....

Unique Keywords:
#weed control
Information And Results
Project Deliverables

Weed control, soybean injury, yield, and economic returns are used to rank the various weed control strategies available for use in non-GMO soybean. We are currently working on the economic analysis from the 2018 growing season to determine the most cost-effective of these programs. Premiums are included in the economic analysis. As mentioned earlier these trials are good discussion points for growers at the MSU weed control tour, as well as for the 30+ non-GMO soybean growers that have attended the afternoon tours highlighting weed control in non-GMO soybean. The web-based fact sheets developed from this information are housed at the www.MSUweeds.com web-site and on the MSPC web-site if applicable. This information is also used at winter meetings that focus on weed control in non-GMO soybean.

Final Project Results

Each year weather can impact outcomes of the various herbicide programs examined in the non-GMO soybean study. However, overall results between years remain fairly consistent. This year was cool and wet up to and soon after planting. Weed densities were extremely high in this trial. There was ~99 annual grasses, six common lambsquarters, one Powell amaranth, 24 common ragweed, and one velvetleaf per square foot. Rainfall within the first two weeks of planting and application of the PRE herbicides was 1.53 inches. An additional 6.79 inches of rainfall fell prior to the POST herbicide applications. Overall rainfall provided good incorporation of the PRE herbicides and contributed to initial differences between the treatments. This year soybean injury from the PRE herbicides was relatively high due to the cool temperature and excessive rainfall. Any treatment that contained flumioxazin (Valor or Valor premixes) resulted in soybean injury between 30 and 40%, 28 DAP. Soybean injury was also observed with several other treatments. However, by the time of the POST herbicide treatments 46 DAP only the treatments Valor + Valor XLT, Dimetric Charged, and Valor XLT had 10% injury or higher. Out of the 20 PRE herbicide treatments, seven treatments provided excellent control of all weeds at the time of the POST, so no POST was applied. These treatments were Fierce, Fierce MTZ, Valor + Valor XLT, Zidua PRO, Trivence, Prefix + Metribuzin, and Warrant Ultra + Metribuzin. Weed control remained excellent (>90%) with only Prefix + Metribuzin, and Warrant Ultra + Metribuzin through the last evaluation. However, all other PRE treatments provided greater than 80% control, with the exception of Zidua PRO on common ragweed. The weed that escaped control from the PRE treatments was predominately annual grasses and common ragweed. Some treatments did not provide adequate control of velvetleaf and common lambsquarters at the time of the POST treatments. POST treatments were chosen to control the weeds that had escaped control from the PRE herbicide treatments. The POST herbicides provided varying levels of soybean injury and weed control. The total cost of the herbicide programs ranged from $25.48 to $79.71 (herbicide + application costs). The more inexpensive programs were treatments were the PRE only treatments or one of the one-pass EPOS treatments. Neither of the EPOS programs resulted in >90% weed control. Soybean injury from POST treatments ranged from 3 to 26%, 7 DAT and by 28 DAT soybean injury was insignificant. Twelve of the 22 herbicide treatments evaluated resulted in greater than 90% weed control at the end of the season. There was a significant range in costs of the programs. Overall soybean yield was variable in this trial and 18 of the 22 herbicide programs evaluated ranked amongst the highest yielding. All but three of the highest yielding programs were amongst the programs with the highest economic returns. Of the three higher yielding programs that were not in the highest economic returns, program costs and yield toward the lower range of the higher yields were factors. This year with the excessive rainfall that we had several of our PRE programs held throughout the season and ranked amongst the highest yield and economic returns. However, this is not always the case. In general, it is important to plan on a two-pass program (PRE fb. POST) when growing non-GMO soybean. Throughout the years these programs have consistently provided better weed control, yield, and economic returns, even with the added herbicide and application cost.

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.