In this Iowa study, Vitazyme produced statistically equal yield increases with 80 lb/acre of N compared to 160 lb/acre of N, while both Vitazyme treatments boosted grain yield by 5 to 7% above the untreated
control. There was no benefit to applying additional Vitazyme above the standard 13 oz/acre rate. The highest return on investment was for the extra 80 lb/acre of N of Treatment 4, but this return was followed
closely by two 13 oz/acre applications of Vitazyme (Treatment 2). In terms of the return on investment ratio, Vitazyme applied at the standard rate did the best (2.6:1).