THE NON-PROTEIN NATURE OF A FRACTION OF SOIL ORGANIC NITROGEN

It is shown that not all the nitrogen in organic soils is determinable by the Kjeldahl method. In every sample tested the Dumas method gave a considerably higher percentage of nitrogen.The differences in nitrogen content, as shown by the two methods, vary from 6.4 to 29.6%, hence it is believed that an appreciable fraction of the soil organic nitrogen may be of non-protein nature.