Researchers from The Ohio State University found that gypsum as a soil amendment can remediate soils with high levels of sodium and magnesium
Warren A Dick, an expert in soil science and Doctor of Philosophy at College of Food, Agricultural, and Environmental Sciences of The Ohio State University found that gypsum is a good source of both calcium and sulfur that are required for good crop yield. In a research presented at the 2018 Annual Meeting of the American Society of Agronomy and Crop Science Society of America held during November 10-13 at Texas, the U.S., he reported that gypsum also improved several other soil characteristics. Gypsum helps to enhance the water absorption ability of soil and reduces erosion. It also reduces the runoff of phosphorus from soils to lakes and streams and can boost the quality of various fruits and vegetables.
Gypsum is naturally found in concentrated from in various places and can be extracted from the ground. However, the current research focused on gypsum recovered from coal-fired electricity generating power plants. Gypsum collected from coal plants is called flue-gas desulfurization gypsum and is a byproduct of a process that removes sulfur out of the smoke stacks to reduce air pollution. According to Dick such gypsum is of good quality and its particles are small and uniform in size, which increases its reactivity. He found that gypsum is safe for agricultural use and suggested reusing it for agricultural purposes rather than dumping it in landfills.
Gypsum has high calcium and sulfur content and its chemical formula makes these nutrients more available to plants compared to other common sources of these nutrients. In a chemical context, gypsum is calcium sulfate. Although gypsum changes soil pH to some extent, it can promote better root development of crops and the researcher found that this impact is even higher in acid soils. This can be attributed to the ability of gypsum to counteract the toxic effect of soluble aluminum on root development. Although aluminum does not harm crops, it becomes harmful when soil is acidic. The research also reported that although gypsum is moderately soluble, it can be an excellent source of sulfur over several growing seasons.