Gypsum is a sulphate mineral composed of calcium sulphate dihydrate. It is mainly used to correct soil pH in alkaline soils. It also improves the structure of sodic clay soils. It serves as a source of calcium and sulphur for plant nutrition. The rate of application is 1-2 t/ha.

Gypsum improves aeration and drainage of compacted soil. One of gypsum’s main advantages is its ability to reduce aluminium toxicity, which often accompanies soil acidity, particularly in sub-soils.