不同开垦条件下土壤腐殖质光谱和热重特征分析

doi:10.11924/j.issn.1000-6850.casb2024-0061

摘要/Abstract

摘要：

本研究综合分析了腐殖质的生理活性、化学组成及其与土壤管理实践之间的关系。探讨了腐殖质在促进植物生长、改善土壤质量以及作为生物刺激剂的潜力。研究分别从不同类型土壤样品中提取土壤腐殖质(HS)并研究其光谱学和热重特征，比较开垦因素对土壤HS化学组成和分子结构特征的影响。利用扫描电镜观察土壤HS微观形貌、紫外—可见漫反射光谱分析紫外特征参数SUVA₂₅₄和E₄/E₆的变化、红外光谱分析特征吸收峰的强度以及利用热重分析研究芳香族和脂肪族结构含量的变化。结果表明：HS微观形貌不均匀，表面凹凸不平，存在一些细小颗粒，比表面积较大，开垦因素对黑土HS微观形貌特征的影响相对较小，而对灰土HS微观形貌特征的影响相对较大。由于HS化学组成较复杂，各官能团相互影响，紫外—可见漫反射光谱分析表明，HS不存在明显的特征吸收峰。紫外特征参数SUVA₂₅₄和E₄/E₆分析结果并不相符，因此需要多种手段联用研究土壤HS化学组成和结构特征。红外光谱的分析结果表明，未开垦灰土(AY+AEL)、开垦灰土(PY1)和开垦黑土(PU1) HS包含的酚类、羧酸、含氧官能团、脂肪族和芳香族结构的含量较多。开垦对黑土和灰土的影响不同，开垦后黑土HS的酚类化合物、羧酸、羟基、醌基、脂肪族和芳香族化合物等含量增加，而开垦后灰土HS的脂肪族化合物和烷烃等含量下降。热重分析的计算结果表明，开垦因素增加黑土HS脂肪族结构含量，而降低了灰土HS脂肪族和芳香族结构含量，这与红外光谱的分析结果基本相符。开垦因素对黑土的影响相对较小，而对灰土的影响相对较大，开垦条件下黑土有机碳不易流失，且在一定程度上促进土壤有机质累积，而灰土土壤有机碳氧化分解转变为结构相对简单的化合物，该研究为HS生物化学研究以及合理开发利用土壤资源提供了理论依据。

关键词: 腐殖质, 开垦, 微观形貌, 化学组成, 分子结构, 热重分析, 生理活性, 土壤管理, 有机碳库, 生物刺激剂, 耕作方式, 土壤有机碳稳定性

Abstract:

Soil humic substance (HS) was extracted from different soil types with sodium pyrophosphate (Na₄P₂O₇) solution and its spectral and thermogravimetric characteristics were studied. The effects of reclamation on the chemical composition and molecular structure characteristics of HS were studied by scanning electron microscopy, UV-visible diffuse reflectance spectroscopy, infrared spectroscopy and thermogravimetric analysis. The results showed that the appearance of HS was uneven, and the surface was irregular with some fine particles and large specific surface area. The influence of reclamation on the appearance of black soil HS was relatively small, while on gray soil HS was relatively large. Due to the complexity of HS chemical composition and the interaction of its functional groups, no obvious characteristic absorption peak was observed in UV-Vis diffuse reflectance spectrum. UV characteristic parameters showed that the values of SUV₂₅₄ and E₄/E₆was inconsistent, suggesting that multiple methods were required to study the chemical composition and structural characteristics of soilHS. The infrared spectroscopy results indicated that HS from uncultivated gray soil (AY+AEL), cultivated gray soil (PY1), and cultivated black soil (PU1) contained high contents of phenols, carboxylic acids, oxygen-containing functional groups, aliphatic and aromatic structures. Reclamation had different impacts on black soil and gray soil. After reclamation, the contents of phenolic compounds, carboxylic acids, hydroxyl groups, quinones, aliphatic and aromatic compounds in black soil HS increased, but the contents of aliphatic compounds and alkanes in gray soil HS decreased. Thermogravimetric analysis indicated that reclamation increased the content of aliphatic structure in black soil HS, but decreased the contents of aliphatic and aromatic structure in gray soil HS, which was basically consistent with the results of infrared spectroscopy. The impact of reclamation on black soil was relatively small, while on gray soil was relatively large. Under reclamation conditions, black soil organic carbon was not easy to lost, which to some extent promoted the accumulation of soil organic matter. On the other hand, organic carbon in gray soil was oxidized and decomposed into compounds with relatively simple structures under reclamation. This study provided a theoretical basis for research on HS biochemistry, and development and utilization of soil resources rationally.

Key words: humic substances, reclamation, microscopic morphology, chemical composition, molecular structure, thermogravimetric analysis, physiological activity, soil management, organic carbon pool, biostimulants, tillage methods, stability of soil organic carbon

宋鸽, 胥智强, 孙静思, 赵雪宁. 不同开垦条件下土壤腐殖质光谱和热重特征分析[J]. 中国农学通报, 2024, 40(27): 60-68.

SONG Ge, XU Zhiqiang, SUN Jingsi, ZHAO Xuening. Spectral and Thermogravimetric Analysis of Soil Humic Substances Under Different Cultivation Conditions[J]. Chinese Agricultural Science Bulletin, 2024, 40(27): 60-68.

图/表 6

参考文献 43

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土壤类型		土层/cm	SUVA₂₅₄	E₄/E₆
未开垦黑土	AU1	10~20	0.65	0.99
未开垦黑土	AU2	20~40	0.59	1.02
开垦黑土	PU1	10~20	0.74	1.01
开垦黑土	PU2	20~40	0.73	1.03
未开垦灰土	AY	0~18	0.75	1.07
未开垦灰土	AEL	18~37	0.29	0.86
开垦灰土	PY1	0~15	0.36	0.96
开垦灰土	PY2	15~30	0.46	1.05

土壤类型		土层/cm	SUVA₂₅₄	E₄/E₆
未开垦黑土	AU1	10~20	0.65	0.99
未开垦黑土	AU2	20~40	0.59	1.02
开垦黑土	PU1	10~20	0.74	1.01
开垦黑土	PU2	20~40	0.73	1.03
未开垦灰土	AY	0~18	0.75	1.07
未开垦灰土	AEL	18~37	0.29	0.86
开垦灰土	PY1	0~15	0.36	0.96
开垦灰土	PY2	15~30	0.46	1.05

土壤类型		土层/cm	3472	2447	1611	1391	1140	918
未开垦黑土	AU1	10~20	64.17	8.36	19.64	6.79	11.09	9.86
未开垦黑土	AU2	20~40	41.82	9.14	14.64	2.80	14.41	10.57
开垦黑土	PU1	10~20	95.05	15.47	25.47	7.03	19.41	15.68
开垦黑土	PU2	20~40	56.91	9.31	19.94	7.03	18.72	13.66
未开垦灰土	AY	0~18	92.15	15.10	32.07	10.41	17.63	17.99
未开垦灰土	AEL	18~37	170.26	38.52	58.37	19.54	22.63	33.61
开垦灰土	PY1	0~15	109.49	20.81	32.45	9.50	14.82	18.87
开垦灰土	PY2	15~30	59.40	3.93	12.33	4.14	15.85	9.42

土壤类型		土层/cm	3472	2447	1611	1391	1140	918
未开垦黑土	AU1	10~20	64.17	8.36	19.64	6.79	11.09	9.86
未开垦黑土	AU2	20~40	41.82	9.14	14.64	2.80	14.41	10.57
开垦黑土	PU1	10~20	95.05	15.47	25.47	7.03	19.41	15.68
开垦黑土	PU2	20~40	56.91	9.31	19.94	7.03	18.72	13.66
未开垦灰土	AY	0~18	92.15	15.10	32.07	10.41	17.63	17.99
未开垦灰土	AEL	18~37	170.26	38.52	58.37	19.54	22.63	33.61
开垦灰土	PY1	0~15	109.49	20.81	32.45	9.50	14.82	18.87
开垦灰土	PY2	15~30	59.40	3.93	12.33	4.14	15.85	9.42

土壤类型		土层/cm	低温失重/%	中温失重/%	高温失重/%	高温/中温比值
未开垦黑土	AU1	10~20	7.97	9.36	16.66	1.78
未开垦黑土	AU2	20~40	7.54	10.05	11.64	1.16
开垦黑土	PU1	10~20	7.26	10.33	11.77	1.14
开垦黑土	PU2	20~40	6.13	10.60	12.51	1.18
未开垦灰土	AY	0~18	6.78	10.20	14.31	1.40
未开垦灰土	AEL	18~37	5.85	10.32	11.83	1.15
开垦灰土	PY1	0~15	5.71	7.86	11.67	1.48
开垦灰土	PY2	15~30	6.11	5.36	10.93	2.04