scholarly journals Humic substances elemental composition of selected taiga and tundra soils from Russian European North-East

2017 ◽  
Vol 38 (2) ◽  
pp. 125-147 ◽  
Author(s):  
Evgeny Lodygin ◽  
Vasily Beznosikov ◽  
Evgeny Abakumov
Keyword(s):  
Organic Matter ◽  
Elemental Composition ◽  
Humic Substances ◽  
Humic Acids ◽  
Mineral Soil ◽  
Formation Mechanisms ◽  
Tundra Soils ◽  
North East ◽  
European North ◽  
Organic Matter Stabilization

Abstract Soils of Russian European North were investigated in terms of stability and quality of organic matter as well as in terms of soils organic matter elemental composi­tion. Therefore, soil humic acids (HAs), extracted from soils of different natural zones of Russian North-East were studied to characterize the degree of soil organic matter stabilization along a zonal gradient. HAs were extracted from soil of different zonal environments of the Komi Republic: south, middle and north taiga as well as south tundra. Data on elemental composition of humic acids and fulvic acids (FAs) extracted from different soil types were obtained to assess humus formation mechanisms in the soils of taiga and tundra of the European North-East of Russia. The specificity of HAs elemental composition are discussed in relation to environmental conditions. The higher moisture degree of taiga soils results in the higher H/C ratio in humic substances. This reflects the reduced microbiologic activity in Albeluvisols sods and subsequent conser­vation of carbohydrate and amino acid fragments in HAs. HAs of tundra soils, shows the H/C values decreasing within the depth of the soils, which reflects increasing of aromatic compounds in HA structure of mineral soil horizons. FAs were more oxidized and contains less carbon while compared with the HAs. Humic acids, extracted from soil of different polar and boreal environments differ in terms of elemental composition winch reflects the climatic and hydrological regimes of humification.

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

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
E. V. Abakumov ◽  
O. A. Rodina ◽  
A. K. Eskov
Keyword(s):  
Organic Matter ◽  
Elemental Composition ◽  
Humic Substance ◽  
Humic Acids ◽  
Mineral Soil ◽  
Basal Respiration ◽  
Organic Substrates ◽  
Aromatic Fraction ◽  
Structural Composition ◽  
South Vietnam

Humification is considered to be a global process that is implemented in soils and organic sediments and also in natural water and air. The 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 13C-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. This 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. The humic acids of the phorophyte soil showed the same content of aromatic fraction as the suspended soil. The most comparable soil type in terms of humic substance composition is Cambisols from humid forests of subboreal and subtropical zones. The 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.

scholarly journals Characterization of Soil Organic Matter Individual Fractions (Fulvic Acids, Humic Acids, and Humins) by Spectroscopic and Electrochemical Techniques in Agricultural Soils

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1067
Author(s):  
Aleksandra Ukalska-Jaruga ◽  
Romualda Bejger ◽  
Guillaume Debaene ◽  
Bożena Smreczak
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Humic Acids ◽  
Agricultural Soils ◽  
Fulvic Acids ◽  
Sorption Properties ◽  
Aliphatic Chains

The objective of this paper was to investigate the molecular characterization of soil organic matter fractions (humic substances (HS): fulvic acids-FAs, humic acids-HAs, and humins-HNs), which are the most reactive soil components. A wide spectrum of spectroscopic (UV–VIS and VIS–nearIR), as well as electrochemical (zeta potential, particle size diameter, and polydispersity index), methods were applied to find the relevant differences in the behavior, formation, composition, and sorption properties of HS fractions derived from various soils. Soil material (n = 30) used for the study were sampled from the surface layer (0–30 cm) of agricultural soils. FAs and HAs were isolated by sequential extraction in alkaline and acidic solutions, according to the International Humic Substances Society method, while HNs was determined in the soil residue (after FAs and HAs extraction) by mineral fraction digestion using a 0.1M HCL/0.3M HF mixture and DMSO. Our study showed that significant differences in the molecular structures of FAs, Has, and HNs occurred. Optical analysis confirmed the lower molecular weight of FAs with high amount of lignin-like compounds and the higher weighted aliphatic–aromatic structure of HAs. The HNs were characterized by a very pronounced and strong condensed structure associated with the highest molecular weight. HAs and HNs molecules exhibited an abundance of acidic, phenolic, and amine functional groups at the aromatic ring and aliphatic chains, while FAs mainly showed the presence of methyl, methylene, ethenyl, and carboxyl reactive groups. HS was characterized by high polydispersity related with their structure. FAs were characterized by ellipsoidal shape as being associated to the long aliphatic chains, while HAs and HNs revealed a smaller particle diameter and a more spherical shape caused by the higher intermolecular forcing between the particles. The observed trends directly indicate that individual HS fractions differ in behavior, formation, composition, and sorption properties, which reflects their binding potential to other molecules depending on soil properties resulting from their type. The determined properties of individual HS fractions are presented as averaged characteristics over the examined soils with different physico-chemical properties.

A molecular dynamic study of Soil Organic Matter stabilization mechanisms

2021 ◽  
Author(s):  
Edgar Galicia-Andrés ◽  
Yerko Escalona ◽  
Peter Grančič ◽  
Chris Oostenbrink ◽  
Daniel Tunega ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Clay Mineralogy ◽  
Metal Cations ◽  
Dense Matter ◽  
Chemical Degradation ◽  
Molecular Graphics ◽  
Organic Matter Stabilization ◽  
Reactive Surfaces

<p>It is well known that some fractions of soil organic matter (SOM) can resist to physical and (bio)chemical degradation which can be attributed to factors ranging from molecular properties to the preference for digesting other molecular species by microorganisms. Some mechanisms, by which organic matter is protected, are often referred to as: physical stabilization through microaggregation, chemical stabilization by formation of SOM-mineral aggregates, and biochemical stabilization through the formation of recalcitrant SOM.</p><p>Protection mechanisms are responsible for the accumulation process of organic carbon, reducing the exposure of organic matter and making it less vulnerable to microbial, enzymatic or chemical attacks. In these mechanisms, water molecular bridges and metal cation bridges play a key role. Cation bridges serve as aggregation sites on humic substances, forming dense matter, in comparison to systems where bridges are missing. This effect is enhanced in systems with cations at higher oxidation states.</p><p>By using the modeler tool developed in our group (Vienna Soil–Organic–Matter Modeler, VSOMM2) (Escalona et al., 2021), we generated aggregate models of humic substances at atomistic scale reflecting the diversity in composition, size and conformations of the constituting molecules. Further, we built models of organo-clay aggregates using kaolinite and montmorillonite as typical soil minerals. This allowed a systematic study to understand the effect of the surrounding environment at microscopic scale, not fully accessible experimentally.</p><p>Molecular simulations of the adsorption process of SOM aggregates on the reactive surfaces of led to two observations: 1) the humic substances aggregates were able to interact with the reactive surfaces mainly via hydrogen bonds forming stable organic matter-clay complexes and 2) the aggregates subsequently lost rigidity and stability after metal cations removing, consequently leading to a gradual loss of humic substance molecules, evidencing the role of metal cations in the protection mechanism of soil organic matter aggregates and possibly explaining its recalcitrance (Galicia-Andrés et al., 2021).</p><p>References</p><ul><li>Escalona, Y., Petrov, D., & Oostenbrink, C. (2021). Vienna soil organic matter modeler 2 (VSOMM2). Journal of Molecular Graphics and Modelling, 103, 107817. https://doi.org/10.1016/j.jmgm.2020.107817</li> <li>Galicia-Andrés, E., Grančič, P., Gerzabek, M. H., Oostenbrink, C., & Tunega, D. (2021). Modeling of interactions in natural and synthetic organoclays. In I. C. Sainz Diaz (Ed.), Computational modeling in clay mineralogy.</li> </ul>

scholarly journals Impact of expected global warming on C mineralization in maritime Antarctic soils: results of laboratory experiments

2010 ◽  
Vol 22 (5) ◽  
pp. 485-493 ◽  
Author(s):  
Juliana Vanir de Souza Carvalho ◽  
Eduardo de Sá Mendonça ◽  
Rui Tarcísio Barbosa ◽  
Efrain Lázaro Reis ◽  
Paulo Negrais Seabra ◽  
...  
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Humic Acids ◽  
Incubation Temperature ◽  
Structural Characteristics ◽  
Maritime Antarctic ◽  
Organic C ◽  
Antarctic Soils ◽  
Mineral Soils ◽  
Increasing Temperature

AbstractThis study concerned the fragility of maritime Antarctic soils under increasing temperature, using the C dynamics and structural characteristics of humic substances as indicators. Working with four representative soils from King George Island (Lithic Thiomorphic Cryosol (LTC1 and LTC2), Ornithogenic Cryosol (OG) and Gelic Organosol (ORG)) we evaluated the total organic C and nitrogen contents, the oxidizable C and humic substances. Soil samples were incubated to assess the amount of C potentially mineralizable at temperatures typical of an Antarctic summer (5–14°C). Humic acids showed a higher aliphatic character and a smaller number of condensed aromatic groups, which suggests that these molecules from Antarctic soils are generally less resistant to microbial degradation than humic acids molecules from other regions. Based on 13C NMR spectra of MAS and CP/MAS, samples of soil humic acids of mineral soils (LTC1 and LTC2) have a higher content of aliphatic C, and heteroatom C, with lower levels of carbonyl and aromatic C, when compared with organic matter-rich soils (OG and ORG). Increasing incubation temperature led to a higher rate of mineralizable C in all soils. A sequence of soil fragility was suggested - LTC1 and LTC2 > OG > ORG - which showed a correlation with the Q10 coefficient and the ratio of labile and recalcitrant C fractions of soil organic matter (R2 = 0.83).

Soil organic matter in soils of the Russian Arctic: insights from 13C-NMR spectroscopy

2020 ◽  
Author(s):  
Ivan Alekseev ◽  
Evgeny Abakumov
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Humic Acids ◽  
13C Nmr ◽  
Cold Climate ◽  
Molecular Organization ◽  
Cold Temperatures ◽  
Organic Matter Stabilization ◽  
Global Carbon

<p>Polar soils play a key role in global carbon circulation and stabilization as they contain maximum stocks of soil organic matter (SOM) within the whole pedosphere. Cold climate and active layer dynamics result in the stabilization of essential amounts of organic matter in soils, biosediments, and grounds of the polar biome. Chemical composition of soil organic carbon (SOC) determines its decomposability and may affect soil organic matter stabilization (SOM) rate (Beyer, 1995). This is quite important for understanding variability in SOC pools and stabilization rate in context of changes in plant cover or climate (Rossi et al. 2016). <sup>13</sup>C nuclear magnetic resonance spectroscopy, which provides detailed information on diversity of structural composition of humic acids and SOM, may also be used to study the SOM dynamics under decomposition and humification proceses (Kogel-Knabner, 1997; Zech et al., 1997). This study aims to characterize molecular organization of the humic acids, isolated from various permafrost-affected soils of Yamal region and to assess the potential vulnerability of soils organic matter in context of possible mineralization processes. Organic carbon stocks for studied area were 7.85 ± 2.24 kg m-2 (for 0-10 cm layer), 14.97 ± 5.53 kg m-2 (for 0-30 cm), 23.99 ± 8.00 kg m-2 (for 0-100 cm). Results of solid-state 13C-NMR spectrometry showed low amounts of aromatic components in studied soils. All studied humic powders are characterized by predominance of aliphatic structures, and also carbohydrates, polysaccharides, ethers and amino acids. High content of aliphatic fragments in studied humic acids shows their similarity fulvic acids. Low level of aromaticity reflects the accumulation in soil of lowly decomposed organic matter due to cold temperatures. Our results provide further evidence of high vulnerability and sensitivity of permafrost-affected soils organic matter to Arctic warming. Consequently, these soils may play a crucial role in global carbon balance under effects of climate warming.</p>

scholarly journals Metal Binding and Sources of Humic Substances in Recent Sediments from the Cananéia-Iguape Estuarine-Lagoon Complex (South-Eastern Brazil)

2021 ◽  
Vol 11 (18) ◽  
pp. 8466
Author(s):  
Christian Millo ◽  
Carlo Bravo ◽  
Stefano Covelli ◽  
Elena Pavoni ◽  
Elisa Petranich ◽  
...  
Keyword(s):  
Organic Matter ◽  
Trace Metals ◽  
Humic Substances ◽  
Humic Acids ◽  
Metal Binding ◽  
Binding Capacity ◽  
Stable Carbon Isotope ◽  
Fulvic Acids ◽  
Freshwater Environment ◽  
Estuarine Lagoon

The Cananéia-Iguape estuarine–lagoon complex (São Paulo state, Brazil) is a natural laboratory to study metal binding by humic substances (HS) in subtropical settings. This transitional environment is evolving into a freshwater environment due to water input from the Ribeira River, funneled through the Valo Grande Canal (Iguape). Past mining activities in the Ribeira River basin and maritime traffic are suspected to be potential sources of trace metals in the system. In this study, the trace metal contents of Free Humic Acids (FHA), Bound Humic Acids (BHA), and Fulvic Acids (FA) extracted from sedimentary organic matter were investigated. Moreover, the sources of HS were traced using their stable carbon isotope compositions and C/N ratios. The results suggested a mixed marine–terrestrial source of FHA, BHA, and FA. Copper and Cr were the most abundant trace metals bound to HS. On average, Cu showed concentrations of 176, 115, and 37.9 μg g−1 in FHA, BHA, and FA, respectively, whereas Cr showed average concentrations of 47.4, 86.3, and 43.9 μg g−1 in FHA, BHA, and FA, respectively. Marine FHA showed the highest binding capacity for trace metals, whereas terrestrial FA derived from the decay of mangrove organic matter showed the lowest binding capacity.

scholarly journals Sustainability/resilience of soil organic matter components in an Argentinean arid region .

2014 ◽  
Vol 2 ◽  
Author(s):  
Carolina Vázquez ◽  
Laura Noe ◽  
Adriana Abril ◽  
Carolina Merlo ◽  
Carlos Romero ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Humic Acids ◽  
Arid Region ◽  
Management Practices ◽  
Agricultural Soils ◽  
Fulvic Acids ◽  
Soil Sustainability ◽  
Undisturbed Site

This short communication presents a novel approach to determining the soil sustainability of productive practices in an Argentinean arid region, using the resilience degree of soil organic matter components. The study was conducted in four sites of the Arid Chaco region of the Cordoba province: one undisturbed site, two sites with livestock (with total and with selective clearing) and one site with agriculture. In each site three soil samples were taken and total soil organic matter, fulvic and humic acids, and non-humic substances were analyzed. Variations of each component (%) between each productive practice and the undisturbed site were calculated in order to establish the resilience degree. The livestock soils showed: a) moderate resilience for non-humic substances, b) low resilience for organic matter and humic acids, and c) no resilience for fulvic acids. The agricultural soils showed: a) low resilience for total organic matter and non-humic substances, and b) no resilience for fulvic and humic acids. We conclude that this approach is a powerful tool for establishing management practices according to each particular situation, allowing improved productivity in arid regions.

scholarly journals The relationship between organic matter stocks in coarse woody debris and the stand phytomass in middle taiga pine forests on the European North-East Russia

2017 ◽  
Author(s):  
А.Ф. Осипов ◽  
И.Н. Кутявин
Keyword(s):  
Organic Matter ◽  
Forest Type ◽  
Woody Debris ◽  
Pine Forests ◽  
Stand Age ◽  
North East ◽  
European North ◽  
Dead Trees ◽  
Standing Dead ◽  
Standing Dead Trees

Приведены результаты исследований структуры и запасов крупных древес- ных остатков (КДО) в среднетаежных сосняках европейского Северо-Востока России, различающихся условиями произрастания и возрастом. К КДО относили сухостойные деревья, валеж и пни диаметром более 6 см. Определены запасы древесины и масса органического вещества в отдельных компонентах (сухостой, валеж, пни) КДО, которые зависят от стадии развития насаждения. Так, в перестойном сосняке черничном наблюдаются более высокие концентрации запасов древесины и органического вещества в гниющей древесине, тогда как в средне- возрастных насаждениях сосняков черничных и чернично-сфагновых более низ- кие. Во всех исследованных насаждениях отмечаются сухостойные деревья. Валеж, пни и сломанные на разной высоте деревья присутствуют в восьми насаждениях. Эти элементы КДО отсутствуют в средневозрастных сосновых древостоях черничного и чернично-сфагнового типа. Выявлено, что в валежнике преобладают деревья, древесина которых находится на начальных стадиях деструкции. По литературным данным представлены результаты исследований запа- сов органического вещества и их распределения по фракциям древостоя. Рассчи- тано соотношение между запасами растущих деревьев и КДО, которое варьирует в широких пределах в зависимости от возраста древостоев. Для оценки взаимо- связи между изучаемыми параметрами были использованы литературные дан- ные, содержащие сведения о массе КДО и древостоя для отдельных пробных площадей. Выявлена положительная (r = 0,57), статистически значимая взаимосвязь между изучаемыми параметрами. Полученные данные можно использовать для уточнения и выведения конверсионных коэффициентов, которые послужат для оценки массы КДО в лесных экосистемах крупных регионов. Structure and stocks of coarse woody debris (CWD) are investigated in the eleven pine forests on European North-East of Russia. Objects under study are differing on forest type and stage of developments. CWD included standing dead trees, fallen dead trees and stumps with a diameter of more than 6 cm. Wood volume and organic matter in separate components of CWD are determined. The mass of CWD depends from stand age. The highest concentrations observed in a overmature pine forest of Myrtillus type but the lowest – in middle-aged stands of Myrtillus and Sphagnosa type. Standing dead trees are noted in all investigated objects. Fallen dead trees and stumps are present in eight stands. These elements are absent in the middle-aged pine stands of Myrtillus and Sphagnosa type. The initial stages of wood destruction dominate in the fallen dead trees. Biomass of stands and it distribution on fractions were present on data that published earlier. The correlation between organic matter mass in CWD and biomass was calculated. It varied in vide range depend on stand age. Literature data were used for estimation relationship between parameters under study. These contained information about forest type, age, CWD mass and stand biomass for separate sample plots. We found positive, statistically significant correlation between CWD stocks and stand biomass. The obtained data can be used to refine and deduce conversion coefficients that will serve to estimate the mass of CWD in forest ecosystems of large regions.

Isolation of the humin fraction from soil: preliminary comments

2020 ◽  
Author(s):  
Jerzy Weber ◽  
Elżbieta Jamroz ◽  
Andrzej Kocowicz ◽  
Magdalena Debicka ◽  
Aleksandra Ukalska-Jaruga ◽  
...  
Keyword(s):  
Organic Matter ◽  
Humic Substances ◽  
Soil Analysis ◽  
Mineral Soil ◽  
Ash Content ◽  
Optimal Time ◽  
Distilled Water ◽  
Science Center ◽  
Freeze Dried ◽  
Humin Fraction

<p>The organic matter is the most important component of soil material, which determines most soil properties. Among humic substances, humin fraction has been the least studied to date, although it usually constitutes over half of their composition. This is probably due to the fact, that humin fraction has highly hydrophobic properties and is insoluble at all pH values, which makes its isolation much more difficult, compared to humic (HA) and fulvic (FA) acid fractions. In addition, humin fraction forms very stable humic-clay complexes with mineral part of the soil (Stevenson 1994), which cannot be destructed during humic substances extraction. According to the literature, the methods of humin fraction isolation can be divided into two main groups: (1) extraction by different organic solvents, and (2) isolation by extraction of HA and FA followed by digestion of mineral soil components. Nevertheless, each of these methods has different limitations.</p><p>We investigated some modifications of the latter method, obtaining humin fraction from eight mollic horizons of Chernozems and Phaeozems, which differed in their physico-chemical properties.</p><p>The first step was to separate HA and FA according to IHSS method described by Swift (1996), however we adopted different shaking procedure. To asses differences, each supernatant obtained was analyzed for the carbon content concentration, which corresponded to HA and FA extracted.</p><p>HA and FA free residue was then digested to reduce the content of mineral components. We used several digestion with 10% HF/HCl , as higher concentrations of HF can result in structural alteration of the organic compounds (Hayes et al. 2017). To find the optimal time of the procedure, the ash content was determined following each digestion stage. After the HF/HCl treatment, the residue was rinsed with 10% HCl to eliminate secondary minerals. The residue was washed with distilled water until the neutral pH, then transferred to dialysis membranes and dialyzed with distilled water until a negative Cl<sup>−</sup> test with AgNO<sub>3</sub>. Afterwards the humin fraction was freeze dried. </p><p>Finally, obtained humin fraction contained various ash content, ranged from 6 to 30%, depending on the soil. The conducted test indicated that: (1) the concentration of carbon in supernatant considerably increased as shaking time was extended to 20 hours, and (2) longer than 4 weeks digestion with HF/HCl did not affect the reduction of the ash content of the humin fraction obtained.    </p><p> </p><p>Literature</p><p>Hayes M.H.B., Mylotte R., Swift R.S. 2017. Humin: Its Composition and Importance in Soil Organic Matter. In: Sparks D.L. (ed) Advances in Agronomy, Vol. 143, Academic Press, Burlington, 47–138.</p><p>Stevenson F.J. 1994. Humus Chemistry; Genesis, Composition, Reaction. 2nd ed. John Wiley & Sons., New York.</p><p>Swift R.S. 1996. Organic matter characterization. In: Sparks, D.L., et al. (Ed.), Methods of Soil Analysis. Part 3. Chemical Methods - Soil Science Society of America, Book Series no 5,  1011-1069.</p><p> </p><p>Acknowledgements</p><p>This work was supported by the National Science Center (NCN) Poland (project No 2018/31/B/ST10/00677 “Chemical and spectroscopic properties of soil humin fraction in relation to their mutual interaction with pesticides").</p>

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