SOME CHARACTERISTICS OF THE ORGANIC MATTER EXTRACTED BY DILUTE INORGANIC ACIDS FROM A PODZOLIC B HORIZON

Abstract

Organic matter was extracted from the B21horizon of a podzol soil by both 0.5 per cent HF and 0.5 per cent HCl. Dialysis of the extracts against distilled water reduced the halogen content to less than 0.1 per cent and the iron plus aluminium to between two and three millimoles per gram of organic matter. Further treatment of this water-dialysed material with EDTA and 8-hydroxyquinoline removed almost all of the iron and about two-thirds of the aluminium.The number average molecular weight of the organic matter, as determined by osmometry, ranged between 47,000 and 53,800. Paper electrophoresis studies showed that this organic matter consisted chiefly of one component, negatively charged, dark-brown in colour and mobile over the pH range investigated (1.8 – 9.0). Only traces to small amounts of glucose, galactose, arabinose and xylose were detected by paper chromatography in both the HF and HCl extracts even after hydrolysis. In addition traces of rhamnose were found in the hydrolyzed HF extract.