Gypsum adds to the value of organic amendments. Blends of gypsum and organics increase the value of the other as soil amendments, especially for improvement of soil structure. High levels of soil organic matter are always associated with liberal amounts of calcium decreases burn out of soil organic matter when soils are cultivated by bridging the organic matter to clay.
Calcium is nearly always only marginally sufficient and often deficient in developing fruits. Good fruit quality requires an adequate amount of calcium. Calcium moves very slowly, if at all, from one plant part to another and fruits at the end of the transport system get too little. Calcium must be constantly available to the roots. In high pH soils, calcium is not available enough; therefore, gypsum helps. Gypsum is used for peanuts, which develop below ground, to keep them disease free. Gypsum helps prevent blossom-end root of watermelon and tomatoes and bitter pit in apples. Gypsum is preferred over lime for potatoes grown in acid soils so that scab may be controlled. Root rot of avocado trees cause by Phytophthora is partially corrected by gypsum and organics. Gypsum is a source of fertilizer sulfur. Due to the trend to production of high-analysis fertilizers and due to the need of removing sulfur dioxide emissions in industrial operations to give cleaner air, and more and more sulfur deficiencies are present in agriculture.