White Magnesium Sulphate

Magnesium (Mg) is an essential nutrient for plant growth. It is classified as a macronutrient, as it is needed in relatively large amounts, along with nitrogen, phosphorus, potassium, calcium and sulfur. It plays an important part in the formation of chloroplasts and photosynthesis in plants, and in animal nutrition.

The magnesium in these products is readily available for plant uptake. They can be used to provide supplementary magnesium in high value horticultural crops, and where a quick response is required during the growing season to correct magnesium deficiency. Magnesium Sulphate (Mg) is applied dry to the soil, while Epsom Salts is generally applied in solution, e.g. in fertigation programs and foliar sprays. A typical rate at which Magnesium Sulphate (Mg) is applied to the soil is 100 – 150 kg/ha /annum.

Magnesium Sulphate (Mg) typically contains 9.7 % Mg and 12.9 % S. Magnesium sulfate is hygroscopic. It readily absorbs atmospheric moisture. The Critical Relative Humidity (CRH) of magnesium sulfate at 25O C is in the region of 50%. By comparison, the CRH of Urea is around 75%. Consequently, magnesium sulfate fertilizers have poor storage and handling characteristics. Blends in which Magnesium Sulphate (Mg) is used can deteriorate rapidly in quality, and must be used quickly.