摘要
土壤腐植酸类物质的形成是土壤固碳的重要过程,但对腐植酸类物质形成过程的了解仍不甚清楚,为了丰富土壤腐植酸类物质形成理论,采用富立叶变换红外光谱和固态交叉极化-魔角旋转13C-核磁共振光谱技术分析了紫色水稻土稻草腐解过程中胡敏酸的波谱学特征。结果表明,稻草腐解的前期,胡敏酸的红外光谱所有吸收峰(3364、2933、1653、1599、1508、1461、1421、1331、1225、1126、1033cm-1)强度皆有明显减弱,核磁共振光谱的烷基、多羟基和芳基的共振峰明显减弱且甲氧基的共振峰显著增强,即表明提取的胡敏酸为类胡敏酸的木质素;随着腐解的进行,胡敏酸的红外光谱的吸收峰强度皆显著增强,核磁共振光谱的烷基、芳基和羰基的共振峰增强,即表明此时的胡敏酸已是以木质素残体为核心并结合烷基、酰胺以及糖类物质反应形成的高分子聚合体;稻草腐解的后期,胡敏酸的红外光谱的2933cm-1处的吸收峰强度减弱,1651、1599、1508、1461、1422和1224cm-1处的吸收峰小幅增强,核磁共振光谱的烷基共振峰减弱,甲氧基共振峰增强,表明此时的胡敏酸发生脱烷基(主要是甲基)过程。因此,红外光谱吸收峰强度与核磁共振光谱共振峰强度的规律性变化反映了稻草腐解过程紫色水稻土胡敏酸的形成过程具有阶段性,紫色水稻土胡敏酸的形成过程符合木质素学说。
The formation of humic substances in soils was one important process of carbon sequestration in soil, but until now there was still no detailed understanding on this process. In this paper, spectroscopy technology（ Fourier transform infrared spectroscopy, solid-state CP-MAS Carbon-13 nuclear magnetic resonance spectrometry ） were used to study the humic acids in purple paddy soil applied with rice straw residue, in order to enrich the formation theory of soil humie substances. In the first phases of decomposition of rice straw residue, all the FTIR spectra of humie acids absorption peaks intensities which included 3 364, 2 933, 1 653, 1 599, 1 508, 1 461, 1 421, 1 331, 1 225, 1 126 and 1 033 cm^-1 weakened obviously; alkyl, polyhydroxy and aryl resonance peaks of 13-C NMR spectra weakened clearly, and that the change of methoxy was opposite, which showed that extractive humic acids were a lignin like class humic acid. With the process of decomposing, all the FTIR spectra of humic acids absorption peaks intensities weakened obviously; alkyl, aryl and carbonyl resonance peaks of 13-C NMR spectra were reinforced, which showed that humic acids at this moment were polymers formed by the reaction based on lignin residues, united with alkyl compounds, amide compounds and carbohydrates. In the final of decomposition, the intensity of FTIR spectra absorption peak that ab- sorption frequency was 2 933 cm-1 of humic acids was lower, as well as the intensity of absorption peaks that absorption frequency were 1 651, 1 599, 1 508, 1 461, 1 422 and 1 224 cm^-1 were stronger slightly; alkyl resonance peaks of 13-C NMR spectra was flagging while methoxy resonance peaks were different, which indicated that dealkylation reaction of humic acids occurred. Therefore, the regular changes of the intensity of FTIR spectra absorption peaks and 13-C NMR spectra resonance peaks reflected the formation process of humic acids in purple paddy soil passed through three phases. And the formation process of humic acids in purple paddy soil wa
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2009年第12期2596-2602,共7页
Journal of Agro-Environment Science
基金
国家科技支撑计划课题(2006BAD05801)
国家自然科学基金资助项目(40231016)
关键词
稻草
腐解
胡敏酸
波谱学
rice straw
decomposition
humic acids
spectroscopy
