By Dan Kaiser, nutrient management Extension specialist Selecting the right source of sulfur is critical to ensure enough sulfate-sulfur is present in the soil at key uptake periods. Rapid uptake of sulfur occurs in corn from V5 to early silking when 50 percent of sulfur needed by corn is taken up. Roughly 10 percent of sulfur needed by corn is taken up prior to V5, but this timeframe is still critical and deficiencies early in the growing season can limit yield – particularly in cool and wet springs. Sulfate fertilizer sources like ammonium, potassium and calcium sulfate will provide readily available sulfate to a corn crop. The drawback of these materials is that sulfate can leach through the soil profile immediately after application. While it is possible to leach sulfate, research in Minnesota has demonstrated that sulfate can carry over in medium- to fine-textured soils and be in the soil profile that fall and even the year following application. Fall application of sulfate can
