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.



Location Gothenburg, NE Planting Date 6/03/2019
Soil Type Hord silt loam Harvest Date 10/14/2019 
Previous Crop Corn Potential Yield (bu/acre) 80
Tillage Type Strip tillage Seeding Rate (seeds/acre) 160K
  • 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. 

No visual differences were observed late in the growing season across the entire study when comparing PPO treatments and soybean products.


  • 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.