Since coal use is down so much the farmland in Illinois is getting low in sulfur (air pollution used to provide it) and may now need to be fertilized with sulfur based fertilizers.Air pollution legislation to control fossil fuel emissions and the associated acid rain has worked - perhaps leading to the need for sulfur fertilizers for crop production. A University of Illinois study drawing from over 20 years of data shows that sulfur levels in Midwest watersheds and rivers have steadily declined, so much so that farmers may need to consider applying sulfur in the not too distant future.