Research conducted for more than forty years (prior to approximately 2005) in Iowa rarely noted improved crop yield with sulfur (S) fertilization. Studies during that time period with corn and soybean found yield increase from S fertilizer application only three times out of approximately 200 trials. Research in the early 1980’s also documented sufficient plant available S in the soil profile for crop production on most Iowa soil associations. Results of recent studies (2000-2005) in corn and soybean were consistent with the historical research. An example is research presented at this conference (Sawyer and Barker, 2002) where there was no corn or soybean yield increase from S application at six sites in Iowa across two years.