Gypsum contains 18% sulphur in the form of relatively soluble calcium sulphate. Sulphur is an essential nutrient, with some crops, (e.g. Canola) requiring high levels in the soil.
Soils commonly show sulphur deficiency if they are highly leached (sandier soil types) or haven’t had recent applications of fertilisers containing sulphur.
Gypsum is the cheapest form of sulphur fertiliser. It is normally spread at around 100 to 200kg/ha prior to cropping or over pastures.