RELATIONSHIPS BETWEEN THE NATURE OF SOIL ORGANIC MATTER AND ROOT LIGNINS OF GRASSES IN A ZONAL SEQUENCE OF CHERNOZEMIC SOILS

1976 ◽  
Vol 56 (4) ◽  
pp. 363-371 ◽  
Author(s):  
L. E. LUTWICK ◽  
J. F. DORMAAR
Keyword(s):  
Thermal Decomposition ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Single Species ◽  
Carboxyl Groups ◽  
Ir Absorption ◽  
Grass Roots ◽  
Organic Complexes ◽  
Ir Absorption Spectra

Clay–organic complexes, humic substances, and grass roots were separated from the Ah horizons of soils sampled at undisturbed sites in three Chernozemic soil zones from under dominantly single species of grass. Derivative thermograms (DTG) and infrared (IR) absorption spectra of the soil materials and of the lignins of the grass roots were compared. The data indicated that the organic matter (OM) of the Black soils contained fewer aliphatic groups and more carboxyl groups and was more resistant to thermal decomposition than that of the Brown soils; the OM of the Dark Brown soils was intermediate. The root lignins from the same soils showed many of the same zonal variations in the IR and DTG properties as did the soil OM.

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.

scholarly journals Differences in soil organic matter and humus of sandy soil after application of biochar substrates and combination of biochar substrates with mineral fertilizers

2020 ◽  
Vol 23 (3) ◽  
pp. 117-124
Author(s):  
Dušan Šrank ◽  
Vladimír Šimanský
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Carbon Content ◽  
Humic Substances ◽  
Sandy Soil ◽  
The Other ◽  
Mineral Fertilizers ◽  
Other Hand ◽  
Sheep Manure ◽  
The Impact

The effort to achieve the sustainable farming system in arable soil led to the intensive search for a new solution but an inspiration can also be found in the application of traditional methods of soil fertility improvement as it is shown in numerous examples in history. Recently many scientific teams have focused their attention on the evaluation of biochar effects on soil properties and crop yields. Since there are a lot of knowledge gaps, especially in explanations how biochar can affect soil organic matter (SOM) and humus substances, we aimed this study at the solution of these questions. Therefore, the objective of the experiment was to evaluate the impact of two biochar substrates (B1 – biochar blended with sheep manure, and B2 – biochar blended with sheep manure and the residue from the biogas station) at two rates (10 and 20 t ha-1) applied alone or in combination with mineral fertilizers (Urea was applied in 2018, at rate 100 kg ha-1, and Urea at rate 100 kg ha-1 + AMOFOS NP 12-52 at 100 kg ha-1 were applied in 2019) on the quantity and quality of SOM and humus of sandy soil (Arenosol, Dolná Streda, Slovakia). The results showed that application of the biochar substrates together with mineral fertilizers (MF) had more pronounced effect on the organic matter mineralization in the sandy soil which resulted in low accumulation of soil organic carbon (Corg) and labile carbon compared to biochar substrates treatments without MF. The share of humic substances in Corg significantly decreased by 16, 50, 16 and 24% in B1 at 10 t ha-1, B1 at 20 t ha-1, B2 at 10 t ha-1 and B2 at 20 t ha-1 treatments, respectively, compared to the control. A similar tendency was observed for biochar substrates treatments + MF, compared to MF control. The carbon content of humic substances (CHS) was equal to 4.40 – 5.80 g kg-1 and the biochar substrates had statistically significant influence on CHS content. On average, there was a smaller decrease of CHS in B1 at rate 10 t ha-1 than at rate 20 t ha-1 and no effect of B2 compared to control. The carbon content of fulvic acid (CFA) was 9% higher in B1 at 10 t ha-1, and 20 t ha-1, 47% higher in B2 at 10 t ha-1 and 17% higher in B2 at 20 t ha-1 compared to control. As a result of biochar substrates + MF application, the reduction in CFA was observed. The results showed a decrease of CHA : CFA ratio with association to biochar substrates alone application compared to control on one hand, and a wider of CHA : CFA ratio in biochar substrates + MF treatments in comparison to MF control on the other hand. Humus stability was increased in biochar substrates alone treatments compared to control, on the other hand, compared to MF control, the application of biochar substrates + MF resulted in a lower humus stability.

scholarly journals CO2-C losses and carbon quality of selected Maritime Antarctic soils

2012 ◽  
Vol 25 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Juliana Vanir De Souza Carvalho ◽  
Eduardo De Sá Mendonça ◽  
Newton La Scala ◽  
César Reis ◽  
Efrain Lázaro Reis ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Soil Temperature ◽  
Soil Carbon ◽  
Humic Substances ◽  
Microbial Activity ◽  
Chemical Characteristics ◽  
Maritime Antarctic ◽  
Antarctic Soils ◽  
Humification Degree

AbstractPolar Regions are the most important soil carbon reservoirs on Earth. Monitoring soil carbon storage in a changing global climate context may indicate possible effects of climate change on terrestrial environments. In this regard, we need to understand the dynamics of soil organic matter in relation to its chemical characteristics. We evaluated the influence of chemical characteristics of humic substances on the process of soil organic matter mineralization in selected Maritime Antarctic soils. A laboratory assay was carried out with soils from five locations from King George Island. We determined the contents of total organic carbon, oxidizable carbon fractions of soil organic matter, and humic substances. Two in situ field experiments were carried out during two summers, in order to evaluate the CO2-C emissions in relation to soil temperature variations. The overall low amounts of soil organic matter in Maritime Antarctic soils have a low humification degree and reduced microbial activity. CO2-C emissions showed significant exponential relationship with temperature, suggesting a sharp increase in CO2-C emissions with a warming scenario, and Q10 values (the percentage increase in emission for a 10°C increase in soil temperature) were higher than values reported from elsewhere. The sensitivity of the CO2-C emission in relation to temperature was significantly correlated with the humification degree of soil organic matter and microbial activity for Antarctic soils.

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>

Changes in soil organic matter and soil humic substances following the afforestation of former agricultural lands in the boreal-nemoral ecotone (Latvia)

2019 ◽  
Vol 16 ◽  
pp. e00213 ◽  
Author(s):  
Imants Kukuļs ◽  
Māris Kļaviņš ◽  
Oļģerts Nikodemus ◽  
Raimonds Kasparinskis ◽  
Guntis Brūmelis
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Humic Substances ◽  
Agricultural Lands

scholarly journals Soil organic matter fractions, chemical attributes and aggregation under forestry and agricultural systems

2018 ◽  
Vol 8 (3) ◽  
pp. 459-468
Author(s):  
Cristiane Figueira da Silva ◽  
Marcos Gervasio Pereira ◽  
Júlio César Fernandes Feitosa ◽  
Ariovaldo Machado Fonseca Júnior ◽  
João Henrique Gaia-Gomes ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
Humic Substances ◽  
Secondary Forest ◽  
Agricultural Systems ◽  
Mean Weight Diameter ◽  
P Content ◽  
Chemical Attributes ◽  
Organic Matter Fractions

The aim of this work was to evaluate the influence of the conversion of forest systems to agricultural systems in the organic matter compartments, aggregation and soil chemical attributes, in the Atlantic Forest. The evaluated systems were: annual crop (ACr); perennial agriculture (PAg); pasture; and secondary forest early (SFES), medium (SFMS), and advanced stage (SFAS). Soil samples were collected at the layer of 0-5 cm depth and quantified the total organic carbon (TOC), C of humic substances, oxidizable C, granulometric fractions of soil organic matter (SOM), soil chemical attributes, soil aggregation and glomalin-related soil protein (GRSP-total and GRSP-easily extractable) in different aggregate classes. It was observed a reduction of the TOC, particulate organic carbon (POC), humic substances and oxidizable C in the PAg and ACr areas comparing to pasture and forest systems. Moreover, the pH values increased whereas P content decreased in comparison with SFAS. As for aggregation, the PAg and the ACr decreased by around 35% and 20% the mean weight diameter of aggregates, respectively, compared to the average values found in the forestry systems, and 34% and 45%, respectively in relation to pasture. In general, GRSP-total were reduced by agriculture. Thus, it appears that the agriculture which has been practiced is altering negatively the soil chemical, physical and biological attributes.

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.

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