Pedosphere 6(3): 277--284, 1996
ISSN 1002-0160/CN 32-1315/P
©1996 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Composition and structural features of calcium-bound and iron-and aluminium-bound humus in soils |
| S. U. CHEEMA, XU Jian-Min and YUAN Ke-Neng |
| Department of Soil Science and Agricultural Chendstry, Zhejiang Agricultural University, Hangzhou 31O029 (china) |
| ABSTRACT |
| Calcium-bound and iron- and aluminium-bound humus extracted from different soils collected from north to south of China were characterized by chemical and spectroscopic methods. Meaningful differences in the composition and structure between them were revealed by 13C NMR, visible spectroscopy and elemental analysis. Results showed that the contents of carbon, hydrogen and nitrogen were higher in iron- and aluminium-bound humus than in calcium-bound humus while oxygen content in calcium-bound humus was shown to be higher. The calcium-bound humus had higher C/N and O/C ratios than iron- and aluminium-bound humus. The calcium-bound humic acid (HA1) showed higher E4/E6 ratios than iron- and aluminum-bound humic acid (HA2) while iron- and aluminum-bound fulvic acid (FA2) showed higher E4/E6 ratios than calcium-bound fulvic acid (FA1). An inverse relationship between E4/E6 ratios and aromaticity as determined by 13C NMR spectra was observed for HA and FA from black soil. The 13C NMR spectroscopy revealed that HA2 was more aromatic than HA1. On the other hand, FA1 exhibited a higher aromaticity than FA2. |
| Key Words: humus, organo-mineral complexes, soils |
| Citation: Cheema, S. U., Xu, J. M. and Yuan, K. N. 1996. Composition and structural features of calcium-bound and iron-and aluminium-bound humus in soils. Pedosphere. 6(3): 277-284. |
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