Comparative characterization of humic substances extracted from freshwater and peat of different apparent molecular sizes

Rigobello, Eliane Sloboda; Campos, Sandro Xavier de; Azevêdo, Eduardo Ribeiro de; Dantas, Ângela Di Bernardo; Vieira, Eny María

doi:10.4136/ambi-agua.2022

Cited by 14 publications

(9 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The degree of aromaticity is dependent on the humification of humic substances and represented by a low E 4 /E 6 ratio, showing that little humificated residue is present (Saab and Martin-Neto, 2007). Rigobello et al (2017) reported that the E 4 /E 6 ratio is influenced by molecule size, environmental pH, levels of oxygen, carbon and carboxyl groups, and the age of the humic material. This affects the formation of humic substances, which, according to Stevenson (1994), occurs through three mechanisms: a) microbiological activity releases nitrogenated compounds that react with lignins; b) oxidation of polyphenolic compounds to form quinones that are condensates in reactions with aminated compounds, and c) reduction of sugars that react with aminated compounds and change into macropolymers of dark in color and with high molecular mass.…”

Section: H Nuclear Magnetic Resonancementioning

confidence: 99%

“…Thus, humic fractions tend to increase particle cohesion and aggregate stability, and are associated with the distribution of aggregate particle sizes and conservation of carbon in the soil (Huang et al, 2010;Loss et al, 2016). Examining the spectral characteristics of separate fractions of organic matter can provide important information on how to improve soil quality (Oades et al, 1987;Rigobello et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spectroscopic characterization of humic and fulvic acids in soil aggregates, Brazil

Machado

Franchini

Guimarães

et al. 2020

Heliyon

View full text Add to dashboard Cite

The aim of this study was to characterize humic and fulvic acids using infrared spectroscopy and nuclear magnetic resonance (NMR) in aggregates collected from areas under different crop and soil management systems. Soil samples were collected at depths of 0.00-0.10 m in a trial set up in 1989 with four management systems (no-till, no-till with chiseling every three years, disk harrowing and heavy disking) under two production systems (succession and rotation). In the laboratory, the soil was sieved and separated into two fractions: particle size of 2 mm or more, and less than 2 mm. From each of the samples an aliquot was extracted and the humic and fulvic acids purified for FTIR, UV-VIS and NMR-1 H analysis. The results obtained showed that the structural characterization of the humic and fulvic acid fractions were linked to organic matter left on the soil surface, especially where the agricultural system involved species diversity. Aggregates !2 mm produce higher NMR, UV-VIS and FTIR spectral magnitudes in aromatic and aliphatic structures than those <2 mm. Aggregates collected from soil under no-till retained their aromatic and aliphatic chemical structures, resulting in higher spectral amplitude.

show abstract

Section: H Nuclear Magnetic Resonancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spectroscopic characterization of humic and fulvic acids in soil aggregates, Brazil

Machado

Franchini

Guimarães

et al. 2020

Heliyon

View full text Add to dashboard Cite

show abstract

“…Compared with CK-L, L-An showed lower C/N and higher H/C and O/C ratios, which indicated that more N-containing compounds, carbohydrates and carboxylic acid derivatives, and a smaller aromatic fraction. An increase in the H content indicated a greater proportion of aliphatic C moieties (CH2) than aromatic C moieties (C = C) [15]. During the culture period, the H content of L-An gradually increased from 26.8 to 27.8 g kg −1 , which also confirmed the occurrence of lignin degradation due to the increase in aliphatic C.…”

Section: Elemental Composition Of Microbial Residuementioning

confidence: 65%

“…The H/C ratios show the degree of maturity of the HSs since indirectly, it reflects the presence of more condensed aromatic rings or substituted ring structures. The O/C ratio is considered an indicator of the contents of carbohydrates and carboxylic acid derivatives [15]. As shown in Table 1, the C, H, O + S contents of C-An were all significantly lower than those of CK-C, but C-An had higher N content.…”

Section: Elemental Composition Of Microbial Residuementioning

confidence: 99%

Contribution of Microbial Residues Obtained from Lignin and Cellulose on Humus Formation

Wang

et al. 2019

Sustainability

View full text Add to dashboard Cite

The contribution of microbial residues formed on lignin and cellulose to the formation of humus (HS) was investigated. The microbial residues formed by Aspergillus niger (A. niger) in the cultures of cellulose and lignin in a fluid medium were structurally characterized by elemental analysis, differential thermal analysis (DTA), FTIR spectroscopy and CP/MAS 13 C NMR spectroscopy. Compared to cellulose itself, the microbial residue from cellulose contains more aromatic compounds and N-containing compounds and fewer carbohydrates and carboxylic compounds. A. niger improved the thermal stability and aromaticity of the cellulose. However, compared with that on lignin, more N-containing compounds, carbohydrates and carboxylic acid derivatives and less aromatic material were found in the microbial residue from lignin. Regardless of whether the carbon source was cellulose or lignin, A. niger utilized the N in the fluid medium to synthesize its own cells, and eventually, they could transfer the N into the microbial residue; in addition, the O-alkyl species dominated over the alkyl and aromatic compounds in the microbial residue. Although the molecular structures of the components of the microbial residue from lignin tended to be simpler, they were more alkylated, more hydrophobic and less aliphatic than those from cellulose. During culture with A. niger, the cellulose underwent degradation and then a polymerization, which led to an increased degree of condensation but a lower degree of oxidation, providing essential precursor substances for HSs formation. However, lignin underwent oxidative degradation. The microbial residue from lignin had a lower degree of condensation and a higher degree of oxidation.

show abstract

“…Humic acids have been discovered to be connected with aggregate particle size distribution and soil carbon preservation in order to improve particle cohesion and aggregate stability [4]. By studying the spectrum properties of different fractions of SOM, it can provide significant information on how to improve soil quality [14,15]. The use of species diversity in agricultural management substantially increases the quality of SOM, thus effectively influencing the relationship between soil aggregates [16].…”

Section: Introductionmentioning

confidence: 99%

Quantifying Mechanistic Detachment Parameters Due to Humic Acids in Biological Soil Crusts

Abbood

Al-Madhhachi

2021

Land

View full text Add to dashboard Cite

Humic acid (HA) is a material that could be used to decrease erosion and improve soil structure. It is also known that biological soil crusts (biocrusts) have a major role in soil stabilization, but the mechanism is not well understood in the presence of HA, especially with mechanistic soil detachment rate parameters (b0 and b1) of the Wilson model, where b0 is the dimensional soil detachment parameter and b1 is the dimensional soil threshold parameter. Therefore, this study intends to (1) investigate the effect of different humic acid (HA) concentrations (0%, 4%, and 8%) on mechanistic soil detachment rate parameters (b0 and b1,) in the Tigris Riversides of the Gheraiat region, Baghdad City, Iraq, of the crusted versus uncrusted soils using a small scale model of the jet erosion tests (mini-JET) at different curing periods (1 week, 2 weeks, and 3 weeks), and (2) examine the impact of HA on b0 and b1 parameters versus some soil characteristics, such as electrical conductivity, cation exchange capacity, and soil organic matter for uncrusted and crusted soils. Thirty-six undisturbed soil specimens (18 for crusted soils and 18 for uncrusted soils) were acquired from the Tigris Riverbank. On these specimens, the mini-JET was used to determine the mechanistic cohesive soil erodibility parameters b0 and b1. The results showed that the value of b0 decreased up to 60% with an increase in curing times for crusted soils until they reached their optimum values at 2 weeks. There was no consistent pattern for b1 at different curing times. As the concentration of HA increased, the value of b0 decreased up to 86% and 99% for crusted and uncrusted soils, respectively. HA significantly improved electrical conductivity, exchange capacity, and organic matter in the soil and reduced soil erodibility. This study provides the benefits of adding HA to the soils as a soil stabilizer using a low-cost technique, which is the JET instrument.

show abstract

Comparative characterization of humic substances extracted from freshwater and peat of different apparent molecular sizes

Cited by 14 publications

References 27 publications

Spectroscopic characterization of humic and fulvic acids in soil aggregates, Brazil

Spectroscopic characterization of humic and fulvic acids in soil aggregates, Brazil

Contribution of Microbial Residues Obtained from Lignin and Cellulose on Humus Formation

Quantifying Mechanistic Detachment Parameters Due to Humic Acids in Biological Soil Crusts

Contact Info

Product

Resources

About