FRACTIONATION OF ACID-SOLUBLE COMPONENTS OF SOIL ORGANIC MATTER USING POLYVINYL PYRROLIDONE

Abstract

Fractionation of fulvic extracts of a Muck soil using adsorption on insoluble polyvinyl pyrrolidone (PVP) permitted the separation of polyphenolic components from those of predominantly polysaccharide nature. Further separation of major fractions into molecular size fractions was achieved by membrane diafiltration. Marked differences between fractions were found with respect to elemental analysis, atomic H/C ratios and polysaccharide content. For horizon samples developed under grass and forest cover, the proportion of fulvic carbon recovered in the polyphenolic fraction varied from 18 to 67%. Lowest proportions were found in grassland Ah samples (mean 24%), and highest proportions in Podzol B horizons (mean 55%). The distribution of subfractions obtained by the fractionation procedure appeared promising as a means of differentiating organic matter accumulated in different environments.