The increased use of fertilizers that contain little or no sulfur and the decrease in atmospheric sulfur deposition from industrial emissions have resulted in lower soil sulfur content and increasing soil sulfur deficiencies worldwide. Sulfur for plant nutrition can be applied directly as elemental sulfur, sulfur-bentonite mixes, ammonium sulfate, potassium sulfate, or superphosphates. Nearly 60 percent of all sulfur consumption is in the production of phosphate fertilizers. Nearly 10 percent of additional consumption is used in other agricultural applications, including the production of nitrogenous fertilizers and plant nutrient sulfur. The largest sources of elemental sulfur are petroleum refining and natural gas processing at numerous facilities throughout the United States.
Elemental sulfur is mined at a few locations worldwide.
Smaller quantities of sulfur are recovered as sulfuric acid at nonferrous metal smelters, and minor amounts are recovered at coking operations. The majority of U.S. imports come from Canada, the largest sulfur exporter in the world. FAIR made significant changes in long-standing U.S. agricultural policies. Farmers now may determine what crops to plant on the basis of market conditions, which may alter fertilizer consumption because of the differing nutrient requirements for different crops. The CRP, the Federal Government's largest environmental improvement program, is a voluntary program designed to decrease topsoil erosion, increase wildlife habitat, and protect ground and surface waters by reducing runoff and sedimentation.