This International Standard specifies a method suitable for the reduction of a sample of a solid fertilizer to a smaller quantity such as may be used for analysis or for further reduction after suitable comminution. By choosing suitable equipment, the method is applicable to the reduction of a sample of any mass above a minimum defined by the size and number of particles. The method can be applied to the division of samples into a number of equally representative sub-samples. Other reduction devices and methods are described in annex A but they are not as accurate as the recommended procedure. This International Standard does not include information on the methods of obtaining the original sample.