Chemodestructive fractionation of soil organic matter

Popov, Alexander I.; Rusakov, Aleksei V.

doi:10.1134/s1064229316060107

Cited by 4 publications

(6 citation statements)

References 14 publications

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“…It has been established that the content of humus in virgin soils corresponds to its average content: in gray forest soil it was 4.88%, in ordinary chernozem -4.34% (Figure 1 A study of the bichromate oxidizability of humus showed a certain predominance of the easily oxidizable fraction in the virgin gray forest soil (Figure 2 Moderately and hardly oxidizable forms in it are 25 and 30%, respectively, which indicates the presence of a balanced system of humic substances that is resistant to external influences [9,10]. The ordinary chernozem on the virgin lands turned out to be more enriched in easily oxidized forms of SOM (54%) compared to the gray forest soil, 33% are hardly oxidizable forms.…”

Section: Resultsmentioning

confidence: 97%

“…Each fraction (part of oxidized SOM) is expressed as a percentage of the total carbon content of organic compounds (Ctot). To obtain results in differential form, the previous one was subtracted from each subsequent result (the amount of oxidized organic material) [9,10].…”

Section: Methodsmentioning

confidence: 99%

“…Passive forms of humus determine the physicochemical properties of soils. In general, labile organic matter (LOM) plays the role of an energy-plastic buffer that protects conservative, structure-determining humic substances from microbial destruction during vegetation (and/or in other cases) when the needs of heterotrophic biota for energy and metabolites of the plastic metabolism change during anabolism [ 1,[7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

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Chemodestructive fractionation of humus as an indicator of the functional state of soil organic matter

et al. 2023

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The content, composition, and properties of humus are the most important characteristics that reflect the features of modern soil formation, the genesis and evolution of soils, and their agrogenic transformation. The main criteria for assessing soil fertility are traditionally the content and reserves of organic matter in soils. At the same time, the decrease in soil fertility is associated not so much with a decrease in the total content of humus, but with the loss of its labile forms, which determine the life of the soil, its most important agronomic properties and crop yields. One of the integral indicators characterizing the state and functioning of soil organic matter (SOM) is the ratio of stable and labile forms of organic compounds obtained by chemodestructive analysis. The determination of the bichromate oxidizability of humus showed that the virgin soils of the Southern Cis-Baikal region contain an equal amount of stable and labile forms of organic compounds. Accordingly, the humus in them is a stable and balanced system in relation to external influences. Plowing led to a significant decrease in the easily and hardly hydrolysable humus fractions. In the fallow areas, the upper part of the humus horizon, in terms of the ratio of humus fractions, approaches virgin soils, and the lower part approaches the arable horizons of agricultural soils. The method of permanganate oxidizability of humus revealed a noticeable enrichment in easily oxidizable forms of virgin and, especially, fallow soils of the region. Compared to them, agricultural soils contained noticeably less labile humus, which indicates a sharp decrease in their fertility.

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Section: Resultsmentioning

confidence: 97%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Chemodestructive fractionation of humus as an indicator of the functional state of soil organic matter

et al. 2023

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“…During the laboratory studies of all samples (organic and mineral), pH values were measured in the soil:water suspension (1:2.5) at static conditions using a pH meter ("Expert-pH", Saint Petersburg, Russia). In 29 samples from the mineral horizons, the content of total organic carbon was analyzed using a K 2 Cr 2 O 7 wet-combustion method [22]. Organic carbon stocks were calculated using the data on the carbon content, the thickness of the studied horizons, and their bulk density determined on the basis of the volumetric cylinder method.…”

Section: Laboratory Analysis and Data Treatmentmentioning

confidence: 99%

“…The latter separates different SOC fractions on the basis of resistance to oxidation or by the destruction of the mineral phase, solubility, and hydrolysability [19,20]. The boundary between labile and stable SOM in many studies is given by the resistance to oxidation [21] using K 2 Cr 2 O 7 as an oxidizing agent [22,23].…”

Section: Introductionmentioning

confidence: 99%

Labile and Stable Fractions of Organic Carbon in a Soil Catena (the Central Forest Nature Reserve, Russia)

Enchilik

Aseyeva

Semenkov

2023

Forests

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The composition of soil organic carbon (SOC) is an important soil quality indicator. We investigated the effect of site-specific soil-forming factors on plant debris and SOC properties along a soil catena with Retisols and Stagnosols in a mixed coniferous–deciduous forest. We examined sites at the summit and middle slope positions with relatively well-aerated soils and sites at footslope positions with waterlogged soils. The concentrations of labile and stable pools of SOC were determined using the method of three-stage chemodestruction. The degree of litter decomposition was calculated, and ash content was determined in the folic and histic soil horizons. The results of our study showed that SOC mostly accumulated in the forest litter and histic horizons of Stagnosols at the footslope positions. The forest litter, folic, and histic horizons were dominated by labile carbon. Equal concentrations of labile and stable carbon were typical of the mineral horizons. The location of the soil in the catena affects the partition and characteristics of SOC in umbric and albic soil horizons. SOC was found to be more stable in the soils at the footslope positions compared to the soils in other locations, because of the lower decomposition of plant remains. Larger stocks of organic carbon, including labile carbon, were restricted to the footslope catena positions.

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