Many soybean growers are interested in the use of foliar fertilizers and multitudes of products are marketed to growers. Growers often use these products while applying fungicides and/or insecticides during early soybean reproductive development. However, with low profit margins, the effect of foliar fertilizers on soybean yield and economic return is important to understand.

Several commonly recommended foliar fertilizer products across the United States were evaluated to determine their impact on yield applied prophylactically at soybean growth stage R3 (beginning pod) (Table 1). All products were applied at this timing based on common fungicide and/or insecticide application timing where these products are often co-applied.

Research has now been conducted over two years (2019 and 2020) at 7 North Carolina locations (Table 2) and 46 locations across the United States (Figures 1 and 2). Based on 46 site years of data generated across the United States capturing many yield environments, we saw no impact on soybean yield of the evaluated foliar fertilizer products applied prophylactically at beginning pod (R3). Without an impact on soybean yield from these products, the likelihood of a positive on-farm ROI from investing in these products is unlikely. We would recommend our growers invest in soybean management areas that have been proven to have a consistent impact on yield