This European Standard specifies a method for the extraction of total calcium, total magnesium and total sodium and for the extraction of total sulfur present in the form of sulfates, so that the same extract may be used for the determination of each nutrient required. The method is applicable to fertilizers listed in Regulation (EC) 2003/2003, Annex I [2], for which a declaration of total calcium, total magnesium, total sodium, and total sulfur in the form of sulfates is provided for in this Regulation.