What is the difference between Mg and MgO in K-Mag Fertilizer?
The magnesium content of K-Mag is expressed as 11% in elemental magnesium (Mg) and about 18.5% when expressed as magnesium oxide (MgO). From the early days of chemical analysis, the traditional way of expressing chemical content was to do so in the oxide form, e.g., MgO. Mathematically, the 11% of magnesium in K-Mag is 66% greater when the weight of oxygen (O) is added to the Mg. This does not change the amount or percent of elemental magnesium (Mg) present. MgO is simply another mathematical way of expressing the same thing.
