Co-Granulated and Blended Zinc Fertilizer Comparison for Corn and Soybean

A new co-granulated formulation of monoammonium phosphate (MAP) including S and Zn could allow for more uniform nutrient distribution. A six site-year study evaluated the effects of blended phosphorus (P) sources [MAP and diammonium phosphate (DAP)] and zinc amounts (0, 2.2, and 5.6 kg Zn ha-1) compared to co-granulated fertilizer, MicroEssentials® Sulfur-10 (MES10™) (12-40-0-10S) and MicroEssentials Sulfur and Zinc (MESZ™) (12-40-0-10S-1Zn), on corn and soybean response. Fertilizers were broadcast applied for corn and the carry-over effect on soybean was determined. Ear leaf P, S, and Zn concentrations at Novelty in 2013 and 2014 were within the sufficiency range regardless of treatment, even though initial soil test values were low-medium. Yields were similar to the N only control for all site-years except at Novelty in 2013, where MAP+ZnSO4 at 2.2 kg Zn ha-1, MAP+Super Zn at 5.5 kg Zn ha-1, and DAP+AMS were 540 to 570 kg/ha greater. The amount of Zn fertilizer (2.2 vs. 5.6 kg Zn ha-1) also showed no significant effect on yield. Applications of P or Zn generally increased their concentrations in post-harvest soil samples. Fertilizer applied for corn indicated some differences in soybean plant nutrient concentrations, but it had no effect on total plant nutrient uptake, grain yield or quality. At Novelty, soybean plant Zn concentration was greater at 5.6 kg Zn ha-1 compared to 2.2 kg Zn ha-1, while Albany showed an increase in whole soybean plant Zn concentration with SuperZn compared to ZnSO4. Carry-over fertilizer from corn showed limited effects on soybean response the following year.