Paramagnetic Properties of Humic Substances in Taiga and Tundra Soils of the European Northeast of Russia

Лодыгин, Е. Д.; Beznosikov, V. A.; Василевич, Р. С.

doi:10.1134/s1064229318080070

Cited by 9 publications

(19 citation statements)

References 20 publications

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“…Groups of structural compounds were identified by the following chemical shifts values (Lodygin, ): 200–185 ppm, carboxyl group and amidic carbonyl; 185–160 ppm, aromatic C of phenols and phenol esters; 160–140 ppm, alkyl aromatic; 140–110 ppm, protonize aromatic carbon, bridgehead C; 110–95 ppm, cellulose anomeric carbon and hemiacetal carbon; 95–60 ppm, resonance region of C─H bonds, secondary alcohols, and other carbon atoms bound to oxygen; 60–45 ppm, methyl group resonance region of aliphatic and aromatic ethyl ethers, amino acid carbons, and methyl esters of carboxylic groups; 60–45 ppm, methyl group resonance region of aliphatic and aromatic ethyl ethers, amino acid carbons, and methyl esters of carboxylic groups; 45–32 ppm, resonance region of quaternary carbon and CH carbons; 32–27 ppm, resonance region of CH 2 alkyl structures in transconformation; 27–10 ppm, resonance region of alkyl methyls and CH 2 units.…”

Section: Methodsmentioning

confidence: 99%

“…The aromatic fraction content was assessed by summing of 110–140 + 140–160 + 160–185 + 185–200 ppm areas, and the aliphatic carbon content was summarized at aliphatic 10–27 + 27–32 + 32–45 + 60–95 + 95–110 ppm (Lodygin, ).…”

Section: Methodsmentioning

confidence: 99%

“…Groups of structural compounds were identified by the following chemical shifts values (Lodygin, 2016)…”

Section: Characterization Of Hasmentioning

confidence: 99%

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Assessment of postfire soils degradation dynamics: Stability and molecular composition of humic acids with use of spectroscopy methods

2017

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The effect of wildfires on the soils of the south taiga and forest‐steppe environments of Central Russia (Histic Spodosols and Eutric Fluvic Arenosols) was investigated in terms of the content and quality of humic acids (HAs) using instrumental spectroscopic methods (solid‐state carbon‐13 nuclear magnetic resonance and electron spin resonance). The bulk elemental composition of HAs was not essentially altered in postfire soils; however, the organic matter of fire‐affected superficial soil layers was characterized by changes in the structural composition and biochemical activity levels. Solid‐state carbon‐13 nuclear magnetic resonance spectroscopy showed that there is an intensive increase in aromatic compounds in HA molecules in soil from both the south taiga and forest‐steppe environments. There is a pronounced and statistically significant decline of aliphatic chain content in response to exposure to fire. The free radicals content and the degree of molecular stabilization assessed with electron spin resonance showed an essential alteration of the HAs, expressed in the increase in the radical's portion, in postfire soils compared with that found in soils not exposed to fire. It was also shown that the accumulation of aromatic compounds indicates only apparent stabilization of HAs due to the loss of periphery alkylic carbon species, which was confirmed by destabilization of the molecules as illustrated by the increase of free radicals.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Assessment of postfire soils degradation dynamics: Stability and molecular composition of humic acids with use of spectroscopy methods

2017

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“…If one compares the soils investigated with soils of various natural environments, soils investigated will present an intermediate version between soils with a large degree and small degree of humification. Aromatic compound content is higher than in tundra or taiga soils, but lower than in Mollisols [3,8,38,46]. e most comparable soil type in terms of humic substance composition is the Cambisol soil from humid forests in subboreal and subtropical zones.…”

Section: Resultsmentioning

confidence: 98%

“…Humification of plant residues caused a decrease in both the H/C and O/C ratios. us, these values are typical for the average standard HAs [46,47]. Data on elemental composition of the HAs indicate that one method of humification is implemented in all three soils investigated.…”

Section: Resultsmentioning

confidence: 99%

Humification and Humic Acid Composition of Suspended Soil in Oligotrophous Environments in South Vietnam

Abakumov

Rodina

Eskov

2018

Applied and Environmental Soil Science

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Humification is considered to be a global process that is implemented in soils and organic sediments and also in natural water and air. e term "suspended soils" has become increasingly common in recent years. Suspended soils are defined as the part of the organic matter that has not undergone the full decomposition process and has not turned into the humus of terrestrial soils. Suspended soils were shown to contain higher total nitrogen, phosphorus, and potassium contents than the forest soil, but the moisture content in suspended soils was significantly lower. Our study of the structural composition of humic substances in suspended soils was conducted with an aim of evaluating the humification rates and structural composition of humic acids in the suspended soil in tropical forests of South Vietnam. Soil samples from three selected areas were investigated: the soil under phorophytes (mineral soil presented by samples of topsoil of the typical dry savanna landscape) and two soils from epiphytous formations. Samples were collected from savanna-type sparse communities, located on oligotrophous plains in Phú Quốc Island (South Vietnam) in 2015. General properties of the soil and the elemental composition of suspended soils were determined, and the humic substance chemical composition was evaluated using solid state 13 C-NMR. Data obtained showed that the pH of the soils under phorophytes was higher than in the suspended soils; basal respiration did not tend to change indices between soils under phorophytes and suspended soils, but the suspended soil was less enriched by nitrogen than the soil under phorophytes.is can be related to the total amount of organic matter exposed to humification in various soils and to the presence of an essential portion of mineral particles in the soil under phorophytes. Data on elemental composition of the humic acids (HAs) indicated that one method of humification is implemented in all three soils that were investigated. e humic acids of the phorophyte soil showed the same content of aromatic fraction as the suspended soil. e most comparable soil type in terms of humic substance composition is Cambisols from humid forests of subboreal and subtropical zones. e humification process implemented in suspended soils showed the absence of mineral compounds or mineral fine earth, which indicated that humification in conditions of pure organic substrates can result in formation of deep humified organic matter, as shown by humic acids with an essential aromatic fraction content.

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Comparison of the Properties of Humic Acids Extracted from Soils by Alkali in the Presence and Absence of Oxygen

et al. 2019

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Paramagnetic Properties of Humic Substances in Taiga and Tundra Soils of the European Northeast of Russia

Cited by 9 publications

References 20 publications

Assessment of postfire soils degradation dynamics: Stability and molecular composition of humic acids with use of spectroscopy methods

Assessment of postfire soils degradation dynamics: Stability and molecular composition of humic acids with use of spectroscopy methods

Humification and Humic Acid Composition of Suspended Soil in Oligotrophous Environments in South Vietnam

Comparison of the Properties of Humic Acids Extracted from Soils by Alkali in the Presence and Absence of Oxygen

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