ABSTRACT
FIGURE 14 Simplified scheme for the extraction and fractionation of humified materials in soil. (After Stevenson, 1986.)
comparison, are by far the largest component of organic matter in inorganic soils (70-80%) and principally consist of the complex compounds humic acid (HA) and fulvic acid (FA) and the hydroxybenzoic acid derivatives formed via oxidative degradation of HA and FA.
