This European Standard specifies a method for the determination of 'total' nitrogen in soil improvers and growing media. The Kjeldahl method determines ammonium-N, nitrate-N and organic N content of soil improvers and growing media. Nitrogen in N-N-linkages, N-O-linkages and some heterocyclics (especially pyridine) is only partially determined. The procedures described herein apply only to those samples that are supplied to the laboratory in the form in which they shall be used for their intended purpose.