Soybean Product Response to PPO Herbicides

• PPO herbicides, such as sulfentrazone and flumioxazin, are important residual herbicides in a soybean weed control program.

• Soybean injury from these herbicides has occurred early in the growing season, typically from cool, wet growing conditions.

• Questions have arisen if there are differences in how soybean varieties respond to these herbicides.

• The study was set up as a split plot with three replications where PPO herbicide was the whole plot and soybean product was the subplot. 

• Nine soybean products (listed below in Table 1), ranging in maturity from a 2.5 to 3.5 MG, were evaluated. 

• PPO herbicides applied at planting (June 5, 2019) included:

  • Sulfentrazone at 0.3125 lb ai/acre
  • Flumioxazin at 0.096 lb ai/acre
  • Untreated 

• Plots were sprinkler irrigated and weeds were controlled as needed with no additional fungicide or insecticide applied. 

• Plots were harvested, and yield was calculated.

   

• The main factors of the research, PPO herbicide treatment and soybean product, impacted yield.

  • Figure 1 reports the average yield across all soybean products, where sulfentrazone negatively impacted yield while the flumioxazin treatment and the untreated plot had similar yields.  
    
    • Potential soybean injury from flumioxazin and sulfentrazone is dependent on weather conditions around application. In this instance, no response was observed from flumioxazin.
      

• Although the interaction of soybean product by PPO herbicide was not significant, the values are listed in Table 1 to provide additional insights. 

• PPO herbicides can impact soybean yield differently.

• Farmers should weigh the benefits of flumioxazin or sulfentrazone as part of their residual weed control program against the potential negative impact on yield these herbicides can sometimes cause.  

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