ALKALINE PERMANGANATE OXIDATION OF THE ORGANIC MATTER OF THE A0 AND B21 HORIZONS OF A PODZOL

Abstract

The organic matter of the A₀ and B₂₁ horizons of a podzol soil has been oxidized with alkaline permanganate under conditions similar to those employed by Bone et al. (1, 2). Using a slight excess of alkaline permanganate, about 65 per cent of the carbon of the A₀ horizon was oxidized to CO₂, 23 per cent to oxalic acid and 2 per cent to acetic acid. The remaining 10 per cent resisted oxidation to these products. Under the same conditions 92 per cent of the carbon of the B₂₁ horizon was oxidized to CO₂, 7 per cent to oxalic acid and 1 per cent to acetic acid.In order to obtain additional identifiable products less drastic conditions were used. The organic matter of the A₀ horizon was oxidized at a KMnO₄/organic matter ratio of 4.7-1 and that of the B₂₁ horizon at ratios of 2.5-1 and 5.0-1.The products of oxidation were fractionated by the scheme of Bone et al. (1). While the mean composition of a substantial portion of the CO₂-free oxidation products approximated to that of benzene di- and tricarboxylic acids and that of another fraction to saturated open chain acids, numerous attempts to isolate these acids in pure forms were unsuccessful. Reasons for the failure to isolate these acids are advanced.