A farmer recently asked Ken Ferrie: “With organic matter above 3.5%, do I need to worry about applying sulfur?” “Today, we are seeing pretty substantial sulfur responses in our corn plots at and above 3.5% organic matter,” Ferrie says. “I still believe, in total, 3.5% organic matter soils will supply enough sulfur. The issue is those soils just don't supply sulfur quickly enough in the spring.”