Update:
We observed a significant treatment (P=0.0063) and location effect (P<0.0001) on yield but no significant treatment (P=0.9362) or location effect (P=0.5849) on relative yield (calculated as a percent compared to the mean yield for untreated control for the trial location) or test weight. There were no significant differences in relative yield between treatments; however, the wide row treatments did yield significantly higher at the WYE location. There was a lot of variability in the yield at the WMREC location, which could be due to excessive rainfall. WMREC location received the most rainfall during the growing season out of the three trial locations. Foliar fungicides can occasionally keep plants greener for longer. We did not observe any green stem treatment effects, nor any significant differences in NDVI measured after fungicide application. The most prevalent disease present in this trial was frogeye leafspot, but it was not prevalent enough at any of the locations to warrant a disease rating.

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Research on the Impacts of Row Spacing and Fungicide Timing on Disease Control and Profitability in Double Crop Soybeans found that average crop yield was significantly affected by fungicide/row width treatments and location, but not relative yield (calculated as a percent compared to the mean yield for untreated control for the trial location) or test weight. Although there were no significant differences in relative yield between treatments, wide row treatments did yield significantly higher at one location where all three wide row (15” rows) soybean treatments yielded significantly more than narrow row treatments (7.5” rows). Excessive rainfall may have contributed to increased variability in the yield at a different location. Although foliar fungicides can occasionally kept plants greener for longer, no green stem treatment effects, nor any significant differences in NDVI (plant greenness) were measured after fungicide application in this study. The most prevalent disease present in this trial was frogeye leafspot, but it was not prevalent enough at any of the locations to warrant a disease rating.

Heavy and frequent rainfall throughout 2018 may have contributed to a significant amount of the variability observed in the data. Foliar fungicides applied at R1 or R3, on narrow or wide row soybeans, did not provide any agronomic or plant health benefits. There was no significant treatment effect on relative yield, test weight, plant greenness, or green stem. Trials performed by other researchers in 2017 had opposite results and this between-year variability in results as well as weather challenges in the 2018 trial indicate that more data needs to be collected over multiple years and sites to improve the robustness of the dataset and to make sound production recommendations for growers in the Maryland region.