One question we get often is about products that claim to improve soybean yields and profits. NC soybean farmers are presented with a variety of products that claim to boost their yields and the NC Soybean Producers Association has worked with NCSU Extension to evaluate these products over the last 6 years. The goal of this research is to provide growers with an unbiased and trusted source to about the efficacy of these products to aid you in making decisions about what products, if any, you should incorporate into your operation.
While products have varied from year-to-year, this trial has generally included foliar fungicides, foliar fertilizers, and stress reducers. The test was conducted across 19 different N.C. environments from 2013-2018 with different products having been evaluated a different number of times. The number of environments a product was evaluated in is included in the graph and only products that were tested multiple years are reported here. Confidence in the results increase the more times and environments a product has been tested.
When combining over the 19 trial environments and various fungicide products evaluated, fungicide use provided on average a 2 bu/a yield advantage when compared to the nontreated control. This yield advantage varied by environment and a large increase in yield was seen in some environments with no increase was seen in others. A number of factors can influence the effectiveness of a fungicide application including the soybean variety (and the resistance package it carries) and environmental conditions (heat, moisture, disease pressure, soybean biomass) as these both can impact the foliar disease pressure.
The multi-mode of action (MOA) fungicides evaluated (Priaxor, Quadris Top, Stratego Yld) provided a 2.5 bu/A yield advantage on average over the nontreated control, whereas the single MOA fungicides only provided a 1.6 bu/A yield advantage on average over the nontreated control. The yield advantage provided by the double MOA fungicides may indicate the presence of fungicide-resistant diseases, which require additional inputs to manage. In addition to the yield increases from the use of a multi-MOA fungicide, using a multi-MOA fungicide is beneficial for fungicide-resistance management.
Several foliar fertilizer products have been evaluated over multiple years in this trial. Significant yield increases were seen when Soar, Ironman, or Smart B-Mo were applied, but there was no significant increase observed with N-Boost or Smart Quatro.
The stress reducers evaluated in this trial (Photon and Bioforge) did not significantly impact soybean yield in the environments tested. Also, sugar applied with or without Bioforge did not impact soybean yield.
When considering adding inputs to a management program it is essential to look at not only the potential yield increase but also to consider the potential return. The cost of the product as well as the cost of application should be considered when deciding which products to use. Of the foliar products evaluated in this trial, foliar fungicide use at early reproductive development would provide the most consistent positive impact on soybean profit compared with other foliar inputs evaluated.