Aromaticity of Humic Substances in Soils

Hatcher, Patrick G.; Schnitzer, M.; Dennis, L.W.; Maciel, Gary E.

doi:10.2136/sssaj1981.03615995004500060016x

Cited by 280 publications

(118 citation statements)

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“…Subdivision of the spectrum was made by the commonly used scheme of Malcolm (1990). The degree of aromaticity of HS (α) was calculated by the procedure of Hatcher et al (1981). Aggregability of HS was assessed according to Beyer et al 1993.…”

Section: Methodsmentioning

confidence: 99%

Spectral characterization of selected humic substances

Enev¹,

Pospíšilová²,

Klučáková³

et al. 2014

Soil Water Res.

104

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Enev V., Pospíšilová L., Klučáková M., Liptaj T., Doskočil L. (2014): Spectral characterization of selected humic substances. Soil & Water Res., 9: 9-17.Current concern for soil quality has stimulated research on soil organic matter (OM). Humic substances (HS) of different origin were compared applying ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), "steady-state" fluorescence spectroscopy, and 13 C nuclear magnetic resonance ( 13 C NMR).Sodium humates samples were isolated from soil (Gleyic Luvisol), compost, and South-Moravian lignite from the mine Mír in Mikulčice. Sodium humates (SH) were extracted by a conventional procedure recommended by the International Humic Substances Society (IHSS). Results showed that the presence of O-containing functional groups (carbonyl in aldehydes and ketones, carboxyl in carboxylic acids, ester and ether groups) are in the order of compost > soil > lignohumate > lignite. Further, results of FTIR, fluorescence spectroscopy, and 13 C NMR suggested that samples of sodium humates isolated from soil, compost, and lignite were a more polycondensed, oxidized, unsaturated, humified, and aromatic structure. On the other hand, commercial lignohumate (LH) had very simple structural components and wide molecular heterogeneity. Furthermore, a small molecular size and weight, low degree of aromatic polycondensation, low level of conjugated chromophores and fluorophores, and low humification degree were characteristic for commercial LH. It should be noted that the sample of commercial LH was characterized by 13 C NMR analysis with a slightly higher value of aromaticity α in comparison with the sample of compost. The application of non-destructive analytical methods such as UV-VIS, FTIR, 13 C NMR, and fluorescence spectroscopy help us to provide main characteristics of selected humic substances.

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Section: Methodsmentioning

confidence: 99%

Spectral characterization of selected humic substances

Enev¹,

Pospíšilová²,

Klučáková³

et al. 2014

Soil Water Res.

104

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“…Aliphatic carbon (C aliph %) is represented in the δ 15-106 ppm spectral region. The degree of aromaticity of HA (α) was calculated by the procedure of Hatcher et al (1981). Statistical results were evaluated in STATGRAPHIC 5.0.…”

Section: Methodsmentioning

confidence: 99%

The influence of humic acid quality on the sorption and mobility of heavy metals

Barančíková¹,

Makovníková²

2003

Plant Soil Environ.

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Mobile and potentially mobile forms of heavy metals are probably one of the most important toxic hazards in the environment. Besides pH, which is a factor influencing the mobility/availability of heavy metals to the greatest extent, the content and mainly the quality of soil organic matter play a very important role in the evaluation of heavy metal behaviour in the environment. The fraction of metals bound to organic compounds is exclusively associated with humic substances and particularly with humic acids (HA). A relationship between the parameters reflecting the actual structure of humic acids and mobile or potentially mobile fractions of heavy metals was studied in 12 soil localities representing different soil types. It can be stated on the basis of the acquired data that heavy metals tend to form complexes with soil organic matter that are different for each metal. The results suggest that copper is bound mainly in an unavailable form (significant correlations of fraction IV with HA parameters) and cadmium prefers exchangeable forms (significant correlations of fraction I with HA parameters) and is more available. It can be assumed on the basis Spearman's correlations that mobile fractions of cadmium are predominantly bound to the aliphatic part of humic substances, and copper prefers strong bonds to humic acids with a high degree of humification.

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“…Aliphatic carbon (C aliph %) is represented the δ 15106 ppm spectral region. The degree of aromaticity of HA (α) was calculated by the procedure of Hatcher (Hatcher et al 1981).…”

Section: Methodsmentioning

confidence: 99%

Changes of humic acids structure on selected key monitoring localities of arable soils

Barančíková¹

2002

Plant Soil Environ.

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Soil fertility is largely determined by the content and quality of soil organic matter. SlovakRepublic monitoring system includes evaluation of soil humus content, basic humic parameters and also chemical structure of humic acids (HA). Changes in humic acids structure on five selected key localities during monitoring period (1994–2000) are presented in this study. Among soil types, essentially between Chernozem and Planosol, in elemental analysis, optical parameter and 13C NMR parameters significant differences determined by Student’s test were observed (Tables 2 and 3). During monitoring period small oxidation trend mainly on Calcaric Fluvisol and Planosol HA expressed by increase of oxygen content and O/C, O/H ratio was observed. Oxidation trends during monitoring period confirm also position of Calcaric Fluvisol and Planosol HA on van Krevelen diagram. Changes in optical parameter E1%6and content of carboxylic groups for the period of monitoring were negligible. Some changes throughout monitoring in 13C NMR parameters were recorded. On all observed HA considerable decrease of carbon in region 106–143 ppm, characteristic for aromatic and olefinic carbon with C–C, C–H bond, was observed. Spectroscopic parameters are in good agreement with elemental analysis and carboxylic groups. Joint relationships between changes in determined parameters are expressed by significant linear correlations. Predominantly between parameters calculated from 13C NMR spectra and data of elemental analysis and optical parameter E1%6highly significant linear correlations (R > 0.93) are found (Table 4).

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Aromaticity of Humic Substances in Soils

Cited by 280 publications

References 0 publications

Spectral characterization of selected humic substances

Spectral characterization of selected humic substances

The influence of humic acid quality on the sorption and mobility of heavy metals

Changes of humic acids structure on selected key monitoring localities of arable soils

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