土壤有机质的重要性和复杂性一直是国内外学者研究的热点。 土壤腐殖质作为土壤有机质的主体, 是土壤肥力的重要物质基础, 在土壤养分循环和土壤结构方面发挥着重要作用。 胡敏素是土壤腐殖质重要组分, 它占土壤有机C和有机N的绝大部分, 同时也是较稳定的腐殖质组分, 对营养元素(C, N, S等)固持和有效性, 以及在土壤肥力和生态环境等方面起着重要作用。 以黑土长期定位试验(始于1979年)为基础, 利用差热分析、 红外光谱和核磁共振光谱分析Hu分子结构变化特征。 结果表明, 各施肥处理可以明显增加土壤有机碳含量, 以有机无机肥配施增加效果最为显著, 各施肥处理土壤Hu含量之间有差异, 但不显著。 土壤Hu的热性质表明, 土壤施入有机肥后具有较高的可分解有机质和脂族结构, 而单施化肥处理具有较高可分解有机质的同时, 芳香结构较多。 Hu的红外光谱也表明, 单施有机肥和有机无机肥配施均可提高土壤Hu的2 920/1 620比值, 其脂族性增强, 芳香性减弱, 单施有机肥处理增加土壤Hu分子中脂族链烃的比例效果高于其他处理。 13C核磁共振波谱分析显示, 与CK相比有机无机肥配施可以提高土壤有机碳稳定性, 而单施化肥处理有机质分解程度增加, 稳定性降低。

The importance and complexity of soil organic matter have been a hot topic both at home and abroad. As the main body of soil organic matter, soil humus is an important material foundation of soil fertility and plays an important role in soil nutrient cycling and soil structure. Humin is an important component of soil humus, which accounts for the majority of soil organic C and organic N. It is also a relatively stable humus component. Humin plays an important role in the fixation and availability of nutrient elements (C, N, S, etc.), soil fertility and ecological environment. Based on the long-term localization test of black soil (which began in 1979), the variation characteristics of Hu molecular structure were analyzed by differential thermal analysis, infrared spectroscopy and nuclear magnetic resonance spectroscopy. The results showed that all fertilization treatments could significantly increase the content of soil organic carbon, and organic and inorganic fertilizers had the most significant effect. There were differences in Hu content among different fertilization treatments, but not significant. The thermal properties of soil Hu showed that the decomposable organic matter and aliphatic structure were higher when organic manure was applied, while the decomposable organic matter and aromatic structure were higher when chemical fertilizer was applied alone. The infrared spectra of Hu also showed that the ratio of Hu in soil increased by 2 920/1 620 with the application of organic fertilizer and organic-inorganic fertilizer alone, and the aromaticity of Hu was weakened. The effect of applying organic fertilizer alone on increasing the ratio of aliphatic chain hydrocarbons in Hu in soil was higher than that of other treatments.13C NMR spectroscopy analysis showed that compared with CK, organic and inorganic fertilizers could improve the stability of soil organic carbon, while the decomposition degree of organic matter increased and the stability decreased under the single chemical fertilizer treatment.