Fractionnement et analyse des complexes organo-mineraux de sols bruns et de chernozems

Bruckert, S.; Kilbertus, G.

doi:10.1007/bf02211687

Cited by 18 publications

(5 citation statements)

References 6 publications

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“…Well on the contrary, 'non-ideal', non-massive, selective extractants are of particular interest for our work. Sodium tetraborate (NaTB henceforth) or sodium pyrophosphate (NaPP) have been used as mild extractors to obtain specific SOM fractions, associated to silt and clay surfaces by mild bonds or metal bridges (Bruckert, 1979;Schnitzer and Schuppli 1989), and the sequence NaTB -NaPP -NaOH was proposed for SOM fractionation in the organo-mineral complex (Bruckert and Kilbertus, 1980). González-Prieto et al (1989) described an extended version of that method, which involved a further extraction with NaOH after reduction of Fe oxides with dithionite, and another after destruction of silicates with hydrofluoric acid (HF).…”

Section: Introductionmentioning

confidence: 99%

Ecosystem type effects on the stabilization of organic matter in soils: Combining size fractionation with sequential chemical extractions

et al. 2019

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Section: Introductionmentioning

confidence: 99%

Ecosystem type effects on the stabilization of organic matter in soils: Combining size fractionation with sequential chemical extractions

et al. 2019

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“…Clays and humic compounds (traditionally related to enzyme activity) are concentrated in the < 50 μm fraction, and physically recognizable non‐transformed plant debris is concentrated in the 2000–100 μm fraction. In the microaggregate (50–0 μm) fraction there are niches occupied by microbial cells covered by polysaccharidic substances ( Bruckert & Kilbertus 1980). Many soil enzymes might be associated with these microbial cells or with humic colloids and anionic clays or both ( Perez‐Mateos & Gonzalez Carcedo 1985).…”

Section: Introductionmentioning

confidence: 99%

Characterization of β‐d‐glucosidase extracted from soil fractions

Busto

Pérez-Mateos

2000

European J Soil Science

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Summary One way to study the state in which stabilized extracellular enzymes persist and are active in the soil is by extraction from the soil, with subsequent fractionation of enzyme–organomineral complexes and characterization of such complexes. In order to investigate the location and characteristics of soil β‐glucosidase, three soil fractions were obtained both from real (undisturbed) soil aggregates and from structural (dispersed in water and physically disrupted) aggregates using two different granulometric procedures. The β‐glucosidase activity of the fraction was then assayed. When the aggregates were dispersed, more than 73% of activity was in the soil microaggregates with diameters of less than 50 μm (SF50). These aggregates were associated with strongly humified organic matter. Solutions of diluted pyrophosphate at neutral pH liberated active β‐glucosidase from all fractions, although the efficacy of extraction varied according to the type of fraction. The SF50 fraction and aggregates of 2000–100 μm obtained by sieving (SF2000) showed the greatest β‐glucosidase activity (34.5 and 36.0%, respectively). Micro‐ and ultrafiltration of SF50 extracts increased the total β‐glucosidase activity, whereas these procedures, applied to the RF2000 fraction, decreased it. Humus–β‐glucosidase complexes in the SF50 fraction, between 0.45 μm and 105 nominal molecular weight limit ( nmwl) (SF50II) and < 105nmwl (SF50III) showed an optimum pH at 5.4, and in the SF50I fraction (> 0.45 μm) the optimum was 4.0. The stability of β‐glucosidase in the aggregates of the smallest size SF50II and SF50III decreased at acid pHs. The presence of two enzymes (or two forms of the same enzyme) catalysing the same reaction with different values of Michaelis constant and maximum velocity was observed in all but one of the β‐glucosidase complexes extracted and partially purified from the SF50 aggregates.

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“…It is known that the main mass of the products of organo mineral interactions is concentrated in the fine particles less than 50-100 µm in size [24,25]. The role of the fine silt fraction in the humus accumulation is comparable with or even higher than the role of the clay fraction [2,6,11,21,22].…”

Section: Resultsmentioning

confidence: 99%

The humus state of the soils of locally hydromorphic landscapes in the lower reaches of the don river

Tishchenko

Безуглова

2012

Eurasian Soil Sc.

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The humus state of rainfed chernozems affected by local waterlogging was studied. The total humus content in the hydromorphic chernozems increases, as well as the content of fulvic acids, whereas the content of nonhydrolyzable residue (humin) decreases. A significant increase in the portions of the third frac tions of humic and fulvic acids is observed. The role of the fine silt and clay fractions in the binding of humic substances increases in the lower horizons of locally hydromorphic soils. The increase in the content of fulvic acids (fulvatization) is mainly due to their predominance in the clay fraction. The latter is specified by the sig nificant narrowing of the C ha to C fa ratio, the lower content of the nonhydrolyzable residue, and the increased content of the clay bound (3rd fraction) fulvic and humic acids. The composition of the humus in the fine silt fraction of the studied soils is characterized by an increased amount of humic acids of the second fraction with a decrease in the relative content of fulvic acids.

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Fractionnement et analyse des complexes organo-mineraux de sols bruns et de chernozems

Cited by 18 publications

References 6 publications

Ecosystem type effects on the stabilization of organic matter in soils: Combining size fractionation with sequential chemical extractions

Ecosystem type effects on the stabilization of organic matter in soils: Combining size fractionation with sequential chemical extractions

Characterization of β‐d‐glucosidase extracted from soil fractions

The humus state of the soils of locally hydromorphic landscapes in the lower reaches of the don river

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