Comparison of Humic Acids from Charred Residues of Susuki (Eulalia,Miscanthus sinensisA.) and from the a Horizons of Volcanic Ash Soils

Abstract

The physico-chemical and spectroscopic properties of humic acids from the charred residues of Susuki (Eulalia, Miscanthus sinensis A.) and from the A horizons of volcanic ash soils were compared. The humic acid (M-HA) of charred Susuki residues belonged to Type A. The elementary composition (C: 61.0%. H: 3.1%. N: 1.5%.0: 34.4%), δlog K (0.57), and RF (97) values of M-HA, except for N content, fell Within the ranges of those of the Type A humic acids in the A horizons of volcanic ash soils. The UV, visible, and IR absorption spectra of M-HA were similar to those of the Type A soil humic acids. Like the Type A soil humic acids, the X-ray diffraction pattern of the M-HA revealed the presence of two peaks at d=3.5 and 2.1Å, corresponding to the (002)- and (10)-bands of graphite, respectively. The Fourier transformation method of (002)-band enabled to show that the M-HA mainly consisted of stacked fractions of two and three layers, as in the case of the Type A soil humic acids.