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 compositio...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 (13)C 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 hasher C/N and O/C ratios than iron- and aluminumbound humus. The calcium-bound humic acid (HA1) showed higher E4/E6 ratios than iron- and aluminumbound humic acid (HA2) while iron- and aluminum-bound pulvic acid (FA2) showed higher E4/E6 ratios than calcium-bound fulvic acid (PA1). An inverse relationship between E4/E6 ratios and aromaticity as determined by (13)C NMR spectra was observed for HA and FA from black soil. The (13)C NMR spectroscopy revealed that HA2 was more aromatic than HA1. On the other hand, FA1 exhibited a higher aromaticitythan FA2.展开更多
文摘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 (13)C 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 hasher C/N and O/C ratios than iron- and aluminumbound humus. The calcium-bound humic acid (HA1) showed higher E4/E6 ratios than iron- and aluminumbound humic acid (HA2) while iron- and aluminum-bound pulvic acid (FA2) showed higher E4/E6 ratios than calcium-bound fulvic acid (PA1). An inverse relationship between E4/E6 ratios and aromaticity as determined by (13)C NMR spectra was observed for HA and FA from black soil. The (13)C NMR spectroscopy revealed that HA2 was more aromatic than HA1. On the other hand, FA1 exhibited a higher aromaticitythan FA2.
