Database Research Summaries2018 Continued Support for Weed Control in Non-GMO Soybean
Research Focus
The focus of this project is to provide growers with information on effective, sustainable weed control strategies in non-GMO soybean.
Objectives
- Continue to develop and evaluate the effectiveness of several herbicide weed control programs in non-GMO soybean.
- Determine the economic returns of these weed control programs.
- Provide this information specifically to non-GMO soybean producers through a web-accessible fact sheet, a field tour and at winter meeting specific to weed control in non-GMO crops.
Results
- The weed populations at the MSU Agronomy Farm were annual grasses (mainly giant foxtail, barnyard grass, and large crabgrass), common lambsquarters, Powell amaranth, common ragweed, velvetleaf, and common purslane.
- Within two weeks of planting and PRE herbicide application there was <0.75-inch of precipitation. This rainfall provided some incorporation of the PRE herbicides, to help manage some of the smaller seeded broadleaf weeds.
- Soybean injury ranged from the PRE herbicides was <10% at the 21 and 34 DAP evaluation.
- Weeds that escaped control from the PRE treatments was predominately common ragweed, and some annual grasses, common lambsquarters, velvetleaf, and common purslane.
- Out of the 20 PRE herbicide treatments, five treatments provided excellent control at the time of the POST, so no POST was applied. These treatments were Surveil + Metribuzin (3.5 + 6 oz), Fierce MTZ (16 fl oz), Valor XLT (3 oz), Zidua PRO (6 fl oz), and Trivence (8 oz). These treatments all provided >90% weed control at harvest.
- Soybean injury from POST treatments ranged from 10-34%, 7 DAT and by 28 DAT only one treatment Harmony + Flexstar + SelectMax + NIS+ AMS still exhibited significant injury (8%). This was mostly in the form of stunted soybeans.
- By 28 days after the POST treatments, all but three treatments provided greater than 90% control of all weed species. In most cases common ragweed was the escape, but control was still greater than 85%.
- Common ragweed control was the species that was the least consistently controlled >90% with the PRE treatments. The fact that the common ragweed population was Group 2 (ALS)-resistant was the most challenging issue with some of the POST treatments. Additionally, Flexstar, Cobra, and Ultra Blazer were used to clean up common ragweed escapes.
- Overall soybean yield for the different herbicide programs was fairly close, ranging from 60.8 to 70 bu/A. Nine of the 20 of these herbicide programs ranked amongst the highest yielding. All of the higher yielding programs, with the exception of one provided greater than 90% weed control. In some cases the programs that did not rank amongst the highest yielding had higher soybean injury from the POST herbicide treatments. Normally this is not a factor but with the later planting and drier conditions throughout July.
- This year the highest yielding program was also the program with the highest economic returns. All of the higher yielding programs, with the exception of one, were amongst the programs with the highest or 2nd highest economic returns.
Importance
- With the increasing cost of soybean seed, particularly seed with herbicide-resistant traits, this information will provide alternatives that may enhance economics and potentially provide growers with alternative strategies for weed control to help delay the evolution of glyphosate-resistant weeds.
- This information could potentially open the doors for other growers to get into the production of soybeans; therefore improving overall grower profitability.
For more information about this research project, please visit the National Soybean Checkoff Research Database.
Funded in part by the soybean checkoff.
