Comparison of Cogranulated Fertilizer to Blends with S and Zn in Corn Production.

High yielding corn and soybean production systems in Missouri have renewed an interest in secondary macronutrient management such as sulfur (S) which is essential for protein formation and zinc (Zn) which is important for enzymes and metabolic reactions. A new formulation of monoammonium phosphate including S and Zn allow for more uniform distribution which include MicroEssential S-10 (MES10) (12-40-0-10S) and MicroEssential S and Zn (MESZ) (12-40-0-10S-1Zn). The objective of this research was to evaluate P rates of MES10 and MESZ formulations to equivalent blends of MAP, Zn, and S at 78 kg P₂O₅ ha^-1 and 123 kg P₂O₅ ha^-1 on grain yields and ear leaf micronutrient concentrations in corn. MESZ at 123 kg P₂O₅ ha^-1 and MAP at 123 kg P₂O₅ ha^-1 had the highest average corn yield (9.16 Mg ha^-1) (6 site-years).  No significant differences among treatments were observed at Novelty in 2012 or 2013, which was probably related to extremely dry conditions in 2012 and a flash drought in 2013.  Grain yields at Albany in 2013 were greatest with MAP + ZnSO₄ + AMS at 123 kg P₂O₅ ha^-1 (9.29 Mg ha^-1). Reduced rates of MAP (78 kg P₂O₅ ha^-1) were generally lower yield than MAP at (123 kg P₂O₅ ha^-1) when yield environments were 8.8 Mg ha^-1 or less there was no significance between rates of MAP.  Ear leaf P concentration was greatest with MAP + AMS at 123 kg P₂O₅ ha^-1 and was similar to the high rates of MAP or MESZ.