In the past several years, sulfur (S) deficiency has been showing up more frequently in Iowa fields. Large yield response has especially occurred in corn and alfalfa fields in northeast Iowa. The increase in S response is thought to be partially due to Iowa receiving less S in the rainfall due to more stringent air pollution regulations, less S fertilizer applications, higher crop yields, and less widespread use of manure. Sulfur fertilizer applications can offer yield increases where S deficiencies are present. The objective of these trials was to evaluate potential for S deficiency and yield response in corn and alfalfa to S applications.