chapter  7
42 Pages

Chemical Composition of Humic Matter

Historical data reported as early as 150 years ago by Mulder and other pioneers in humic acid science, for %C (56%–62%), %H (2.0%–5.5%), and %N (2%–8%), are remarkably within the range of those listed in Table 7.1. However, Orlov (1985) cautions their use for comparison, because they are in the higher ranges, due perhaps to the habit in the old days of drying humic acids at 140°C or higher, and the use of different values in atomic weights.