This European Standard specifies a method for the determination of total and water extractable boron in mineral fertilizers containing more than 10 % boron. This method is applicable to water and aqua regia fertilizer extracts obtained according to prEN 16962 and/or prEN 16964. NOTE A method used for determination of boron in mineral fertilizers containing less than 10 % of boron (spectrophotometric determination by azomethine-H) can be also used for the scope of this method after appropriate dilution of the extracts.