Also, it's a supplementary source of Calcium, a vital plant nutrient. It leaches out excessive amounts of Sodium and Magnesium. Sulfur is the fourth major nutrient, and is needed by your turf in relatively large amounts. One pound of Sulfur is needed for every 10 to 15 pounds of Nitrogen used by plants.
Sulfur increases protein in grass.
Sulfur decreases excessive levels of Magnesium and Sodium in soils. When soils become deficient in Sulfur, plant growth decreases accordingly. Plants use Sulfur in the Sulfate form. The Sulfur in Gypsum is already Sulfate, so there is not waiting period for it to become available. Today's modern fertilizers typically are very low in Sulfur.