Interactive effects of iron oxides and organic matter on charge properties of red soils in Thailand

Soil Research ◽  
2013 ◽  
Vol 51 (3) ◽  
pp. 222 ◽  
Author(s):  
D. Ketrot ◽  
A. Suddhiprakarn ◽  
I. Kheoruenromne ◽  
B. Singh
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Clay Fraction ◽  
Interactive Effects ◽  
Soil Conditions ◽  
Oxide Surfaces ◽  
Fe Oxide ◽  
Fe Oxides ◽  
Red Soils ◽  
Variable Surface

Iron (Fe) oxides and organic matter (OM) play important roles in maintaining the fertility of highly weathered soils. The main objective of this study was to investigate the interactive effects of variable surface charge minerals, particularly Fe oxide minerals, and OM on the charge properties of red soils from Thailand. We also evaluated the effect of the 5 m NaOH procedure, used to concentrate Fe oxides from soils, on the charge characteristics of Fe oxide concentrates. Fourteen clay fractions (untreated and OM-free clay fractions), and Fe oxide concentrates of these clays, were used in the study. Cation exchange capacity (CEC) and electrophoretic mobility (EM) were measured for the soil clays, artificial mixtures, and goethite adsorbed with humic acid (HA) and phosphate (P). Kaolinite and Fe oxides (predominantly a mixture of hematite and goethite) were the main minerals in the clay fraction. Results indicated that OM or metal–OM complexes may have blocked or neutralised negatively charged sites on clay minerals. After OM removal these sites became accessible, inducing an increase in CEC and shifting the EM values towards more negative values and the isoelectric point (IEP) towards lower pH for many samples. The CEC values of Fe oxide concentrates prepared by 5 m NaOH treatment were overestimated and their EM and IEP shifted towards more negative values. It is possible that the amorphous phase from clay dissolution was still present in the Fe oxide concentrates, or the adsorption of silicate ions modified the surfaces of Fe oxides concentrates. Humic acid and P adsorbed on Fe oxide surfaces caused the IEP to shift to lower values. In natural soil conditions, a variety of anions can be adsorbed on Fe oxide surfaces, which might lead to higher values of negative charge and lower IEP than observed for pure synthetic minerals.

Sorption of humic acid on Fe oxides, bacteria, and Fe oxide-bacteria composites

2014 ◽  
Vol 14 (8) ◽  
pp. 1378-1384 ◽  
Author(s):  
Li Jiang ◽  
Jun Zhu ◽  
Hui Wang ◽  
Qingling Fu ◽  
Hongqing Hu ◽  
...  
Keyword(s):  
Humic Acid ◽  
Fe Oxide ◽  
Fe Oxides

Soil organic matter and phosphate sorption on natural and synthetic Fe oxides under in situ conditions

2020 ◽  
Author(s):  
Lydia Pohl ◽  
Kristof Dorau ◽  
Christopher Just ◽  
Carmen Höschen ◽  
Kristian Ufer ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Oxide Coating ◽  
Redox Status ◽  
Fe Oxide ◽  
Fe Oxides ◽  
Mn Oxide ◽  
Mn Oxides ◽  
Natural And Synthetic

<p>In redoximorphic soils, iron (Fe) and manganese (Mn) oxides undergo reduction with subsequent oxidation of their reduced counterparts (Fe<sup>2+</sup> and Mn<sup>2+</sup>) impacting nutrient sorption and the stability of soil organic matter (SOM). One tool to investigate the soil redox status is the indicator of reduction in soils (IRIS) method. Thereby, synthetic Fe and Mn oxides are coated onto polyvinyl chloride (PVC) bars, which are typically installed for an operator-defined period in the soil. After removal of the bars we studied organo-mineral associations, which have been formed under field conditions on the surface of the coated bars.</p><p>In this study, each one Mn and Fe oxide-coated redox bar were installed for 30 days in a Mollic Gleysol. A previous study revealed, that the Mn oxide coating facilitated a non-enzymatic redox reaction under anoxic conditions, while Fe<sup>2+</sup> from the soil solution is oxidized to Fe<sup>3+</sup> along the Mn oxide coating and Mn<sup>2+</sup> is removed from the PVC surface [1]. In consequence, in situ Fe oxides formed along the Mn oxide coatings and were further considered as ‘natural’ Fe oxides. This enables us to differentiate between sorption occurring onto the surfaces of ‘synthetic’ Fe oxides from the Fe bar versus ‘natural’ formed Fe oxides along the Mn bar. They were analysed by nanoscale secondary ion mass spectrometry (NanoSIMS) to study the distribution of Fe (<sup>56</sup>Fe<sup>16</sup>O<sup>−</sup>), SOM (<sup>12</sup>C<sup>14</sup>N<sup>−</sup>), and phosphorus (<sup>31</sup>P<sup>16</sup>O<sub>2</sub><sup>−</sup>). NanoSIMS is a spectromicroscopic technique offering a high lateral resolution of about 100 nm, while having a great sensitivity for light elements. In contrast to classic bulk analysis, it offers the possibility to examine the spatial distribution of SOM and phosphorous at the microscale within the intact organo-mineral matrix. </p><p>Image analysis of individual Fe oxide particles revealed a close association of Fe, SOM, and P resulting in coverage values up to 71% for synthetic and natural iron oxides. Furthermore, ion ratios between sorbent (<sup>56</sup>Fe<sup>16</sup>O<sup>−</sup>) and sorbate (<sup>12</sup>C<sup>14</sup>N<sup>−</sup>; <sup>31</sup>P<sup>16</sup>O<sub>2</sub><sup>−</sup>) were smaller along the natural oxides when compared with those for synthetic Fe oxides. We conclude that both natural and synthetic Fe oxides rapidly sequestered SOM and P (i.e., within 30 days) but that newly, natural formed Fe oxides sorbed more SOM and P than synthetic Fe oxides.</p><p> </p><p>[1] Dorau, K.; Eickmeier, M.; Mansfeldt, T. Comparison of Manganese and Iron Oxide-Coated Redox Bars for Characterization of the Redox Status in Wetland Soils. Wetlands 2016, 36, 133–144.</p>

Adsorption of Chloridazon by Soils and their Components

Weed Science ◽  
1991 ◽  
Vol 39 (3) ◽  
pp. 417-422 ◽  
Author(s):  
Maria J. Sánchez-Martín ◽  
Maria Sáanchez-Camazano
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Clay Fraction ◽  
Organic Matter Content ◽  
Clay Content ◽  
Matter Content ◽  
Soil Composition ◽  
Active Components ◽  
Central Spain ◽  
Natural Soils

The effect of soil composition on adsorption of chloridazon by 18 samples of natural soils, with different chemical and textural characteristics, obtained from west-central Spain, was investigated. The effect of removal of organic matter on adsorption and adsorption of the herbicide by the active components of the soils (montmorillonite and humic acid) was also studied. A highly significant correlation was found between the distribution coefficient (Kd) and organic matter content when all the soils or the soils with organic matter content >2% were considered. According to the determination coefficients (r2), organic matter content accounted for 72% of the variance in adsorption in the former case and 92% in the latter. In soils with an organic matter content <2%, there was no correlation between Kd and organic matter content. A significant correlation was observed between Kd and smectite content for soils containing smectite in their clay fraction. Both simple and multiple correlations showed that clay content, excluding the smectite fraction, had a relatively small effect on adsorption of the herbicide. Adsorption of chloridazon by oxidized soils, montmorillonite, and humic acid confirms the effect of organic matter and smectite on adsorption in natural soils.

scholarly journals Humic acid and nitrogen dose application in corn crop under alkaline soil conditions

2021 ◽  
Vol 25 (10) ◽  
pp. 657-663
Author(s):  
Kamran Azeem ◽  
Farah Naz ◽  
Arshad Jalal ◽  
Fernando S. Galindo ◽  
Marcelo C. M. Teixeira Filho ◽  
...  
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Grain Yield ◽  
Block Design ◽  
N Uptake ◽  
Soil Conditions ◽  
Alkaline Soil ◽  
Total N ◽  
Positive Effects ◽  
N Concentration

ABSTRACT Humic acid (HA), as a bio-stimulant and a major component of organic matter (OM), can improve plant physiology, soil fertility, and nutrient availability, mainly in low OM soils. Nitrogen (N) is one of the most important nutrients that affect several metabolic and biochemical activities, leading to improved plant development. This study was conducted to investigate the combined effect of HA and N doses on soil organic matter (SOM) and total N concentration, N uptake, corn growth, and grain yield under conventional tillage at Peshawar, Pakistan. Treatments were tested in a randomized block design with four replicates arranged in a factorial scheme 3 × 4 + 1. The respective doses of HA (1.5, 3,0 and 4.5 kg ha-1) were applied at the corn sowing, whereas N doses (80, 120, 160, and 200 kg ha-1) were applied in three splits (1/3 at sowing, 1/3 at the V5 stage, and remaining 1/3 at the tasselling stage) with one control (no HA and N). The application of HA, regardless of the applied doses, had positive effects on SOM, N concentration, N uptake, corn development, and grain yield. However, the application of 4.5 kg ha-1 of HA was the most effective in promoting SOM (0.83%) and total N (0.31%), shoot biomass (10610 kg ha-1), N uptake (1.13%), and grain yield (3780 kg ha-1), even when combined with the N doses of 80, 120 and 160 kg N ha-1. Increasing N doses positively influenced SOM, N concentration, N uptake, and corn growth. The greatest grain yield was obtained at 150 kg ha-1 of N regardless of HA applied doses.

The point of zero charge of natural and synthetic ferrihydrites and its relation to adsorbed silicate

Clay Minerals ◽  
1982 ◽  
Vol 17 (4) ◽  
pp. 471-476 ◽  
Author(s):  
U. Schwertmann ◽  
H. Fechter
Keyword(s):  
Organic Matter ◽  
Electrophoretic Mobility ◽  
Bulk Composition ◽  
Point Of Zero Charge ◽  
Fe Oxide ◽  
Hydromorphic Soils ◽  
Fresh Waters ◽  
Fe Oxides ◽  
Zero Charge ◽  
Main Component

The point of zero charge (pzc) of synthetic Fe-oxides is well documented and usually ranges between pH 7 and 9 (Parks, 1965; Schwertmann & Taylor, 1977). In contrast, the pzc of natural Fe-oxides has only rarely been determined. Using electrophoretic mobility, Van Schuylenborgh & Arens (1950) found that a natural goethite had a much lower pzc (∼3) than synthetic goethites. They attributed this to better crystallinity of the natural goethite caused by slower crystallization. Soils dominated by Fe- (or Al-) oxides rarely have pzc values as high as those of pure oxides. This is usually attributed to the presence of negatively charged impurities such as clay silicates and organic matter (Parfitt, 1981).Ferrihydrite, a natural, poorly-crystalline Fe-oxide mineral of bulk composition 5Fe2O3.9H2O, occurs in hydromorphic soils (Schwertmann et al., 1982) and is the main component in ochrous precipitates formed when Fe-bearing fresh waters come in contact with air (Schwertmann & Fischer, 1973; Carlson & Schwertmann, 1981). Under these conditions the ferrihydrite is reasonably free of other charge-active minerals. The aim of this study was to find out if the pzc of these natural ferrihydrites differed from those of synthetic samples.

Characterization of dissolved organic matter (DOM) extracted from soils by hot water percolation (HWP)

2010 ◽  
Vol 59 (1) ◽  
pp. 99-108 ◽  
Author(s):  
M. Takács ◽  
Gy. Füleky
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Extraction Methods ◽  
Soil Samples ◽  
Hot Water ◽  
Soil Extracts ◽  
Water Percolation ◽  
Soil Humic Acid

The Hot Water Percolation (HWP) technique for preparing soil extracts has several advantages: it is easily carried out, fast, and several parameters can be measured from the same solution. The object of this study was to examine the possible use of HWP extracts for the characterization of soil organic matter. The HPLC-SEC chromatograms, UV-VIS and fluorescence properties of the HWP extracts were studied and the results were compared with those of the International Humic Substances Society (IHSS) Soil Humic Acid (HA), IHSS Soil Fulvic Acid (FA) and IHSS Suwannee Natural Organic Matter (NOM) standards as well as their HA counterparts isolated by traditional extraction methods from the original soil samples. The DOM of the HWP solution is probably a mixture of organic materials, which have some characteristics similar to the Soil FA fractions and NOM. The HWP extracted organic material can be studied and characterized using simple techniques, like UV-VIS and fluorescence spectroscopy.

Characteristics of fouling due to clay-organic substances in potable water treatment by ultrafiltration

1996 ◽  
Vol 34 (9) ◽  
pp. 157-164 ◽  
Author(s):  
Kim C.-H. ◽  
M. Hosomi ◽  
A. Murakami ◽  
M. Okada
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Humic Acid ◽  
Fulvic Acid ◽  
Size Distribution ◽  
Ultrafiltration Membrane ◽  
Organic Substances ◽  
Decomposition Products ◽  
Microbial Decomposition ◽  
Fouling Materials

Effects of clay on fouling due to organic substances and clay were evaluated by model fouling materials and kaolin. Model fouling materials selected were protein, polysaccharide, fulvic acid, humic acid and algogenic matter (EOM:ectracellular organic matter, microbial decomposition products) and kaolin was selected as the clay material. Polysulfone membrane (MWCO(Molecular Weight Cut-Off) 10,000, 50,000 and 200,000) was used as an ultrafiltration membrane. In particular, the flux measurement of solutions containing algogenic matter used an ultrafiltration membrane of MWCO 50,000. The flux of protein and polysaccharide with coexistence of kaolin increased in the case of the ratio of MW/MWCO being greater than one, but did not increase in the case of the MW/MWCO ratio being below one. In contrast, the flux of fulvic acid and humic acid with coextence of kaolin decreased regardless of the ratio of MW/MWCO. The addition of dispersion agent and coagulant in the organic substances and kaolin mixture solution changed the size distribution of kaolin, and resulted in a change of the flux. EOM and microbial decomposition products decreased with the increase of the fraction of organic matter having molecular weight more than MWCO of membrane. The flux of the algogenic organic matter with coexistence of kaolin decreased with the increase of the amount of kaolin. It was suggested that the decline of the flux with coexistence of kaolin was due to the change of the resistance of the kaolin cake layer corresponding to the change in kaolin size distribution with charge.

scholarly journals DOM degradation by light and microbes along the Yukon River-coastal ocean continuum

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Brice K. Grunert ◽  
Maria Tzortziou ◽  
Patrick Neale ◽  
Alana Menendez ◽  
Peter Hernes
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Salinity Gradient ◽  
Coastal Ocean ◽  
Interactive Effects ◽  
The Arctic ◽  
Yukon River ◽  
Spring Freshet ◽  
Dom Composition

AbstractThe Arctic is experiencing rapid warming, resulting in fundamental shifts in hydrologic connectivity and carbon cycling. Dissolved organic matter (DOM) is a significant component of the Arctic and global carbon cycle, and significant perturbations to DOM cycling are expected with Arctic warming. The impact of photochemical and microbial degradation, and their interactive effects, on DOM composition and remineralization have been documented in Arctic soils and rivers. However, the role of microbes, sunlight and their interactions on Arctic DOM alteration and remineralization in the coastal ocean has not been considered, particularly during the spring freshet when DOM loads are high, photoexposure can be quite limited and residence time within river networks is low. Here, we collected DOM samples along a salinity gradient in the Yukon River delta, plume and coastal ocean during peak river discharge immediately after spring freshet and explored the role of UV exposure, microbial transformations and interactive effects on DOM quantity and composition. Our results show: (1) photochemical alteration of DOM significantly shifts processing pathways of terrestrial DOM, including increasing relative humification of DOM by microbes by > 10%; (2) microbes produce humic-like material that is not optically distinguishable from terrestrial humics; and (3) size-fractionation of the microbial community indicates a size-dependent role for DOM remineralization and humification of DOM observed through modeled PARAFAC components of fluorescent DOM, either through direct or community effects. Field observations indicate apparent conservative mixing along the salinity gradient; however, changing photochemical and microbial alteration of DOM with increasing salinity indicate changing DOM composition likely due to microbial activity. Finally, our findings show potential for rapid transformation of DOM in the coastal ocean from photochemical and microbial alteration, with microbes responsible for the majority of dissolved organic matter remineralization.

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