This Technical Specification specifies a method for the determination of the magnesium content in fertilizer extracts using atomic absorption spectrometry (AAS). This method is applicable to EC fertilizer extracts obtained according to CEN/TS 15960 and CEN/TS 15961@ for which a declaration of the total magnesium and/or water soluble magnesium content is required@ with the exceptions of the following fertilizers according to [4]@ Annex I D relating to secondary nutrients: ?? type 4 (kieserite); ?? type 5 (magnesium sulfate) and type 5.1 (magnesium sulfate solution); ?? type 7 (kieserite with potassium sulfate) to which [4]@ method 8.8@ applies. NOTE Method 8.8 is covered by CEN/TS 16198 (see Bibliography). The method applies to all fertilizer extracts containing elements in quantities that might interfere with the complexometric determination of magnesium.