Humic Acid-Oxidizing, Nitrate-Reducing Bacteria in Agricultural Soils

ABSTRACTThis study demonstrates the prevalence, phylogenetic diversity, and physiology of nitrate-reducing microorganisms capable of utilizing reduced humic acids (HA) as electron donors in agricultural soils. Most probable number (MPN) enumeration of agricultural soils revealed large populations (104to 106 cells g−1soil) of microorganisms capable of reducing nitrate while oxidizing the reduced HA analog 2,6-anthrahydroquinone disulfonate (AH2DS) to its corresponding quinone. Nitrate-dependent HA-oxidizing organisms isolated from agricultural soils were phylogenetically diverse and included members of theAlphaproteobacteria,Betaproteobacteria, andGammaproteobacteria. Advective up-flow columns inoculated with corn plot soil and amended with reduced HA and nitrate supported both HA oxidation and enhanced nitrate reduction relative to no-donor or oxidized HA controls. The additional electron donating capacity of reduced HA could reasonably be attributed to the oxidation of reduced functional groups. Subsequent 16S rRNA gene-based high-density oligonucleotide microarray (PhyloChip) indicated that reduced HA columns supported the development of a bacterial community enriched with members of theAcidobacteria,Firmicutes, andBetaproteobacteriarelative to the no-donor control and initial inoculum. This study identifies a previously unrecognized role for HA in stimulating denitrification processes in saturated soil systems. Furthermore, this study indicates that reduced humic acids impact soil geochemistry and the indigenous bacterial community composition.IMPORTANCEThis study identifies a new metabolic capacity in soil microbial communities that may be responsible for the mediation of significant nitrogen losses from soil systems. Nitrate-dependent humic acid (HA)-oxidizing organisms isolated from agricultural soils were phylogenetically diverse and included members ofAlphaproteobacteria,Betaproteobacteria, andGammaproteobacteria. Advective up-flow columns inoculated with corn plot soil and amended with reduced HA and nitrate supported both HA oxidation and enhanced nitrate reduction relative to no-donor or oxidized HA controls. The additional electron donating capacity of reduced HA could reasonably be attributed to the oxidation of reduced functional groups.

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Effects of Monoculture, Crop Rotation, and Soil Moisture Content on Selected Soil Physicochemical and Microbial Parameters in Wheat Fields

Applied and Environmental Soil Science ◽

10.1155/2012/593623 ◽

2012 ◽

Vol 2012 ◽

pp. 1-13 ◽

Cited By ~ 7

Author(s):

A. Marais ◽

M. Hardy ◽

M. Booyse ◽

A. Botha

Keyword(s):

Soil Moisture ◽

Microbial Communities ◽

Crop Rotation ◽

Management Practices ◽

Agricultural Soils ◽

Soil Microbial Communities ◽

Soil Microbial Activity ◽

Most Probable Number ◽

Probable Number ◽

Soil Microbial

Different plants are known to have different soil microbial communities associated with them. Agricultural management practices such as fertiliser and pesticide addition, crop rotation, and grazing animals can lead to different microbial communities in the associated agricultural soils. Soil dilution plates, most-probable-number (MPN), community level physiological profiling (CLPP), and buried slide technique as well as some measured soil physicochemical parameters were used to determine changes during the growing season in the ecosystem profile in wheat fields subjected to wheat monoculture or wheat in annual rotation with medic/clover pasture. Statistical analyses showed that soil moisture had an over-riding effect on seasonal fluctuations in soil physicochemical and microbial populations. While within season soil microbial activity could be differentiated between wheat fields under rotational and monoculture management, these differences were not significant.

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Agricultural soils strengthening employing humic acids and its effect on plant growth chilli pepper and eggplant

Emirates Journal of Food and Agriculture ◽

10.9755/ejfa.2018.v30.i11.1845 ◽

2018 ◽

Author(s):

Fredy Colpas- Castillo ◽

Arnulfo Tarón Dunoyer ◽

Jairo Mercado Camargo

Keyword(s):

Humic Acid ◽

Plant Growth ◽

Capsicum Annuum ◽

Humic Acids ◽

Agricultural Soils ◽

Solanum Melongena ◽

Chili Pepper ◽

Growth Promoter ◽

Chilli Pepper ◽

Significant Difference

The Humic substance has been recognized widely as a plant growth promoter because they induce changes in root, architecture and dynamics of growth which result in larger root size. The aim of this study was evaluating the effect Humic acids on the chili pepper (Capsicum annuum) and eggplant (Solanum melongena) plants growing in soils fertilized with urea. 200 g of soil were incorporated to the fertilizer once and the Humic acid in concentrations of 0.05%, 0.1% and 0.2%. All measurements growths were carried out during 45 days growth. The finding shows that all treatments cause significant increases (p < 0.05) in the total area of roots. For the chili pepper, the multiple comparison tests of Tukey and Dunnett showed that there was a statistically significant difference between the control soils and the soils containing 0.1% and 0.2% of Humic acid. By the opposite, no statistical differences (p > 0.05) were observed among control soil and those containing 0.05 % of Humic acid. Concerning the eggplant, significant differences were established (p<0.05) between the control and samples incorporated with 0.1% and 0.2% of Humic acid. The Humic acids act as a growth biostimulant in chili pepper plants (Capsicum annuum) and eggplant (Solanum melongena).

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HUMIC ACID CRACKING BY ACTIVATED CLAY CATALYSTS AND IDENTIFICATION OF ITS PRODUCTS

TROPICAL WETLAND JOURNAL ◽

10.20527/twj.v1i1.12 ◽

2015 ◽

Vol 1 (1) ◽

pp. 9-17

Author(s):

Abdullah Abdullah ◽

Rina Twinasty ◽

Taufiqur Rohman

Keyword(s):

Humic Acid ◽

Surface Area ◽

Functional Groups ◽

Humic Acids ◽

Pore Radius ◽

Ash Content ◽

Fixed Bed Reactor ◽

Liquid Smoke

Humic acid is a compound of colloidal,amorphous, and complex aromatic polymerwith functional groups of -COOH (carboxyl), -OH (phenol), and C = O (carbonyl). The presence of these functional groups provides a rationale for assuming that humic acids have a potential to produce phenolic, carboxylic and carbonylic compounds through cracking process. In this study the cracking was done by isolating humic acids from peat soil, and facilitated by a clay catalyst which had been activated. Humic acids were isolated by extracting the acids from the peat with NaOH and HCl. The characterization of humic acids included the determination of the ash content by gravimetric method and the analysis of the functional groups of humic acids by Infrared spectrometer (FTIR). The clay to be activated was shaped into two forms, pellets and 20-40 mesh granules. The clay was activated by immersing it in HCl and NH4NO3, and then calcined. The characterization of catalysts included the determination of acidity and the Si/Al ratio gravimetrically, as well as the analysis of the pore volume, maximum pore radius, surface area and average pore radius by Surface Area Analyzer NOVA-1000. Humic acid cracking was performed by a fixed-bed reactor system at a temperature of 400°C. The Liquid smoke, the product of cracking, was analyzed by GC and GC-MS to determine the number of compounds and major compounds contained in the liquid smoke. The results show that the isolated humic acid had ash content of 9.10%. Activated clay had acidity and Si/Al ratio higher than the clay before actifated. Based on the analyses of GC and GC-MS it can be found out that the major compounds contained in liquid smoke, the product of humic acid cracking with 20-40 mesh catalyst at a temperature of 400°C were phenolic compounds (74.56%), and no carboxylic and carbonylic compounds as the major compounds. The activated clay can be used as the catalyst for humic acid cracking.

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Organic Amendments and Sampling Date Influences on Soil Bacterial Community Composition and Their PredictiveFunctional Profiles in an Olive Grove Ecosystem

Agriculture ◽

10.3390/agriculture11111178 ◽

2021 ◽

Vol 11 (11) ◽

pp. 1178

Author(s):

Laura L. de Sosa ◽

Beatriz Moreno ◽

Rafael Alcalá Alcalá Herrera ◽

Marco Panettieri ◽

Engracia Madejón ◽

...

Keyword(s):

Microbial Community ◽

Bacterial Community ◽

Agricultural Soils ◽

Soil Microbial Communities ◽

Soil Bacterial Community ◽

Olive Grove ◽

Soil Microbial Diversity ◽

Soil Microbial ◽

Soil Bacterial ◽

The Impact

A collapse of soil microbial diversity, mainly due to chemical inputs, has been reported to lead to the degradation of conventional agroecosystems. The use of compost from urban and agricultural waste management, in order to achieve a net gain in the storage of C, is an adequate management of agricultural soils, especially in rainfed conditions. However, the great variability of composts of different maturity and origins and of the soils to which they are added limits the ability to predict the impact of these amendments on the dynamics of soil microbial communities. This study was designed to gain insights on the effect of exogenous organic matter management on the soil bacterial community and its contribution to key functions relevant to agricultural soils. To achieve this, two different types of compost (alperujo or biosolids composts) at two doses were used as soil amendments twice for 3 years in a rainfed olive grove ecosystem. A metagenomic analysis was carried out to assess the abundance and composition of the soil bacterial communities and predicted functions. We only detected a minor and transitory effect on the bacterial abundance of the soil, the structure of the community and the potential functions, less related to the dose or the type of compost than to seasonal variations. Although the result suggests that the soil bacteria were highly resilient, promoting community stability and functional resilience after the addition of the two composts, more efforts are necessary to assess not only the resulting soil microbial community after organic fertilization but the intrinsic microbial community within the organic amendment that acts as an inoculum, and to what extent the changes in its dose could lead to the functionality of the soil.

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Changes in the Humic Acid–Metal Complexation Characteristics Depending on Humification Degree / Humīnskābju – Metālu Kompleksveidošanās Rakstura Izmaiņas Atkarībā No Humifikācijas Pakāpes

Latvian Journal of Chemistry ◽

10.2478/v10161-012-0012-0 ◽

2012 ◽

Vol 51 (3) ◽

pp. 228-237

Author(s):

D. Dudare ◽

M. Klavins

Keyword(s):

Humic Acid ◽

Stability Constants ◽

Humic Acids ◽

Complex Stability ◽

Peat Layer ◽

Raised Bog ◽

Complexing Capacity ◽

Humification Degree ◽

Complexation Process ◽

Complex Stability Constants

The aim of this study is to determine the Cu(II) complexing capacity and stability constants of Cu(II) complexes of humic acids isolated from two well-characterized raised bog peat profiles in respect to the basic properties and humification characteristics of the studied peats and their humic acids. The complex stability constants significantly change within the studied bog profiles and are well correlated with the age and decomposition degree of the peat layer from which the humic acids have been isolated. Among factors that influence this complexation process, molecular mass and ability to form micellar structures (supramolecules) of humic substances are of key importance.

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EFFECT OF IRRIGATION AND GRASSING TO CHANGE SOME OF THE BIOLOGICAL PROPERTIES OF THE MINING OF BROWN CALCAREOUS SOILS

Agricultural Technologies ◽

10.35599/agritech/01.01.04 ◽

2019 ◽

Vol 1 (1) ◽

pp. 29-32

Author(s):

Ruzimurod B. Boimurodov ◽

Zebinisso Q. Bobokhonova

Keyword(s):

Folic Acid ◽

Humic Acid ◽

Humic Acids ◽

Rapid Growth ◽

Growth And Development ◽

Sharp Increase ◽

Humus Content ◽

Calcareous Soils ◽

Biological Properties ◽

Humus Accumulation

In this article is showing, that the irrigation mountain brown carbonate soils prone methods of irrigation and grassing comes the rapid growth and development of natural vegetation, which leads to intensive humus accumulation. Humus content in the upper layer is increased by 0.98% and a significantly smaller severely eroded. Increasing the amount of humus promotes accumulation mainly humic acids, that conducts to expansion of relations the content of humic acid: The content of folic acid. When grassing of soil traced sharp increase in the number associated with the related and R2 O3 humic acid.

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Kinetic Adsorption of Humic Acids Mixture Obtained from Microalgae on Exfoliated Graphite Nanoplatelets

Revista de Chimie ◽

10.37358/rc.18.1.6072 ◽

2018 ◽

Vol 69 (1) ◽

pp. 191-195

Author(s):

Elena Radu ◽

Elena Emilia Oprescu ◽

Cristina Emanuela Enascuta ◽

Catalina Calin ◽

Rusandica Stoica ◽

...

Keyword(s):

Humic Acid ◽

Humic Acids ◽

Alkali Treatment ◽

Exfoliated Graphite ◽

Acid Mixture ◽

Acidic Ph ◽

Graphite Nanoplatelets ◽

Mixture Concentration ◽

Ft Ir ◽

Exfoliated Graphite Nanoplatelets

The dehydration of polysaccharides fraction in the presence of acid catalysts, is a chemical process in which results as secondary product humic matter. In our work, the humic acid mixture was for the first time based on our knowledge extracted from defatted microalgae biomass rich in polysaccharides by standard alkali treatment, followed by precipitation at acidic pH. The dried humic acid mixture has been characterized using infrared spectroscopic measurements (FT-IR). Exfoliated graphite nanoplatelets (xGnP) were used as new adsorbents for this type of humic acids mixture, their adsorption being investigated. The effect of several parameters such as: contact time, concentration of humic acid mixture, concentration of xGnP, temperature and pH of the solutions were studied. The process of adsorption took place with good results, in the following conditions: at a concentration of humic acid mixture of 18.6 mg L-1, an xGnP amount of 0.01 mg in 25 mL of solution, at a temperature of 25 �� and at acidic pH values, in aqueous solution.

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

Agronomy ◽

10.3390/agronomy11061067 ◽

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.

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