This International Standard specifies two methods for the determination of the bulk density (tapped) of solid fertilizers: - the machine-tapping method (method 1); - the hand-tapping method (method 2). These methods are applicable to dry fertilizers only. If the fertilizer has absorbed moisture during transport or storage, it is necessary to dry it in an environmental chamber, with constant low humidity, Prior to the determination. Neither method is suitable for materials which contain a large proportion of particles exceeding 5 mm in diameter. Method 2 is applicable only to spherical granules and to prills. lt is not applicable to sharp-edged grains. NOTE 1 Because of the differentes in tapping technique, the two methods will not necessarily give the same value for the bulk density (tapped).