Will elemental sulfur or gypsum reclaim a saline and/or sodic soil?
Gypsum is generally added to provide a calcium source to displace sodium in the soil. (Gypsum is calcium sulfate, 22.5% calcium). For most soils in Montana east of the continental divide, the soil is already saturated with respect to calcium (as calcium carbonate or lime). Hence, adding gypsum to a soil already saturated with calcium simply elevates the concentration of calcium, favoring formation of calcium carbonate. Elemental sulfur can be used as an amendment at high rates (500-1000 pounds per acre). On soils in Montana east of the continental divide, sulfur is added to stimulate microbial action and formation of sulfuric acid, which lowers pH. As pH decreases, lime is dissolved, and calcium and magnesium replace sodium in soils. However, without adequate drainage and good water to move the sodium out of the soil, little reclamation is gained by adding sulfur.
