Research Article
Fluorescence Spectroscopy and 13C NMR Spectroscopy Characteristics of HA in Black Soil at Different Corn Straw Returning Modes
Table 5
Relative intensity (%) of different chemical shift intervals from 13C CPMAS NMR spectra of HA examined.
| | Treatment | Carbonyl C (%) (160–230 ppm) | Aromatic C (%) (110–160 ppm) | O-Alkyl C (%) (50–110 ppm) | Alkyl C (%) (0–50 ppm) | Alkyl C/O-alkyl C | Aliphatic C/aromatic C | Hydrophobic C/hydrophilic C |
| | CK | 18.58 | 53.98 | 14.45 | 12.98 | 0.898 | 0.508 | 2.027 | | SCR | 18.97 | 53.96 | 14.00 | 13.08 | 0.934 | 0.502 | 2.034 | | MBR | 18.26 | 54.49 | 13.69 | 13.55 | 0.99 | 0.500 | 2.129 | | SEDI | 18.53 | 53.05 | 13.26 | 15.16 | 1.143 | 0.536 | 2.146 |
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Note. CK: no straw application; SCR: straw mulching; MBR: straw deep ploughing; SEDI: straw enrichment and deep incorporation.
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