This greenhouse study with corn grown at four fertilizer rates, each rate having either Vitazyme or no Vitazyme, generally corroborates the usual observation that increasing fertility rates reduce the percentage response of the crop yield. This is thought to be due to the fact that as the crop approaches its maximum yield potential under a given set of environmental conditions, the extent to which Vitazyme can reduce growth stresses of fertility, diseases, water stress, and so forth, and increase yields decreases as the yield limit is approached. Even so, at high yield potentials of active and added fertility (Treatment 8), Vitazyme has been shown in this study to still stimulate the corn yield by 16% over its untreated control treatment (Treatment 7).