When soybean prices are low, inputs need to be carefully considered. Will I get a return on my investment?
In 2019, Ohio State participated in a national protocol to evaluate foliar fertilizer in soybean. Trials were conducted in 13 states and totaled 20 different growing environments (Figure 1). In 2019, only 1 environment (Fond du Lac, Wisconsin) showed a yield benefit associated with foliar fertilizer application. Ohio-specific results are shown in Figure 2. In Ohio, none of the evaluated foliar fertilizer products resulted in a different yield compared with the non-treated control (no foliar fertilizer application). Our results are consistent with previously conducted trials in Ohio. Historically, yield response to micronutrient foliar fertilizer application is rare. For detailed information, see Corn, Soybean, and Alfalfa Yield Reponses to Micronutrient Fertilization in Ohio FactSheet (https://ohioline.osu.edu/factsheet/agf-519).
Although, yield response to micronutrient foliar fertilizer application is rare, there are cases where applications are warranted. In Ohio, manganese is the micronutrient that is most likely to be deficient in soybean. In our work, 2 out of 36 trials have shown a statistically significant yield increase with the application of manganese foliar fertilizer. One responsive location was in northern Ohio in a field with high sand content and dry soil conditions. (Manganese is oxidized to an unavailable form under dry conditions.) The second response location was in northwest Ohio in a field with high clay and high pH.