Kieserite or magnesium sulfate fertilizer. Kieserite Granular is an excellent source of fast-release magnesium and sulphur, both of which are present in their water-soluble form. Fertilization rates of magnesium usually range from 10 to 40 pounds of Mg/acre. Perhaps as important as application rate is the consideration of Mg solubility. Kieserite Granular is particularly useful in alleviating acute magnesium deficiencies in high-value crops, for example, horticultural crops. Product Ingredients: MgO : minimum 22% CaO : 0,30 % Nitrogen Total : 0,63% Fosfor P2O5 : 0,14% K2O : minimum 12% S : minimum 20% Impurities min 14% Moisture max. 10%