Application of gypsum to sodic soils is commonly done to improve soil physical properties.  Effectiveness of gypsum is highly dependent on its dissolution potential over time. The dissolution of gypsum is a function of its particle size, surface area, sample purity, available moisture, and ionic species in solution. This experiment is designed to determine the potential dissolution of both fluidized gas desulfurization gypsum (FGD-gypsum) and natural gypsum in a natric soil from the Golden Valley formation in western North Dakota. Solubility of both products will be determined in solutions having similar ionic strengths and ion compositions as would be found in the natural soil. Gypsum dissolution will be determined using a flow-through system and quantified using sulfate.  Results from these experiments will indicate the potential of using these two gypsum sources as soil amendments in non irrigated, acidic soils receiving less than 50 cm of precipitation per year.