Foliar Fertilization of Soybean in North Carolina and Southeastern Virginia

The purpose of this project was to determine the need for foliar fertilization of soybean. The objectives for this research were (1) to determine soybean plant tissue and yield response to foliar fertilization with commercially sold products and (2) to evaluate profitability of applying such products. Experiments were conducted during the 2019 growing season at four locations in North Carolina and southeast Virginia. Six foliar fertilizers containing formulations of macro, secondary, and micronutrients were applied to R3-stage soybean and compared to an untreated control. Plant tissue samples were collected immediately before application and two weeks afterward to measure the change in tissue nutrient concentration. FertiRain significantly increased iron plant tissue concentration by 8% at two locations. Sure-K significantly reduced loss of nitrogen and phosphorus in the tissue by 7% at one location. Smart B-Mo significantly increased boron plant tissue concentration by 41% at three locations. Smart Quatro increased zinc plant tissue concentration by 27% at one location. HarvestMore UreaMate increased copper tissue concentration by 13% at three locations and zinc by 14% at another, but reduced copper and potassium plant tissue concentration by 17% and 10%, respectively, at one location. Despite plant tissue concentration increases of select nutrients, none of the foliar fertilizers affected yield at any location; therefore, profit decreased by $3.82 to $22.11 per acre, depending on cost of the product at the applied rate. Despite the lack of yield response to foliar fertilizers tested, soybean may respond positively under different environments, hence further research is necessary to determine the need for foliar fertilization.