Separation of melanic and fulvic andisols

Abstract

It has been recognized in Japan and Alaska that vegetational effects in particular, of grass and forest ecosystems contribute significantly to the formation of melanic and fulvic Andisols, respectively (SHOJI et al. 1988a, b). Although the two Andisols have thick, humus-rich horizons, they indicate remarkable differences in the humus characteristics. Melanic Andisols have high humic acid to fulvic acid ratios and contain the A type humic acid characterized by the highest degree of humification. On the other hand, fulvic Andisols show low humic acid to fulvic acid ratios and mostly contain the P type humic acid with a low degree of humification, followed by the B type humic acid (HONNA et al. 1988; SHOJI et al. 1988a, b). These differences in the humus characteristics are closely related to the soil color.