This standard specifies a method for the determination of nitrogen in soil improvers and growing media. The Kjeldahl method determines ammonium-N, nitrate-n, nitrite-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 method is not applicable to liming materials and preformed materials such as mineral wool slabs and foam slabs.