MgO is commonly used as a supplement for magnesium deficient soils especially for crops such as citrus, potatoes, vegetables, fruits and grass pastures.As we know magnesium is a required element in plant photosynthesis. Magnesium Oxide offers an available source of magnesium for various fertilizer applications, especially for Magnesium Sulfate. The specifications: MGO:90%MIN, SIO2:5.5%MAX, CAO:2.5%max, Fe2O3:1%max, Al2O3:1%max, lOI:5%Max, Size:200mesh passing 90%min