Stressing Soybeans to Increase Yield.

Relatively little change in trend line soybean (Glycine max) yields over the previous years has led to many farmers creating management regimes focused on plant stress. Field experiments consisting of two different relative maturities (2.8 RM and 4.5 RM) soybeans were established at three locations across Kentucky in 2013. Each maturity group received a single application, sequential applications, or a combination of the following treatments: BioForge, lactofen, lambda-cyhalothrin with thiamethoxam, and azoxystrobin with propiconazole. Seed yields were compared with an untreated control (UTC), which yielded 4170 and 5496 kg ha-1 for the 2.8 and 4.5 RM soybeans, respectively. Significant seed yield increase was observed in the 2.8 RM soybean for a combination of lambda-cyhalotrhin with thiamethoxam plus azoxystrobin with propiconazole.  A significant yield decrease was observed for BioForge with lactofen on 2.8 RM soybean and treatments containing BioForge and BioForge with lactofen in the 4.5 RM soybean. Prescribed applications of these treatments, regardless of pest pressure, was not a consistent approach to improving yields.