Alexey Sergeevich Sorokin
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Diagnostics of Compaction of Arable Soils in the Transvolga Region in Saratov OblastMoscow University Bulletin. Series 17. Soil science. 2018. 1. p.3-7read more585
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The evidence and factors of the formation of compact horizons in haplic chernozems are discussed. They include a complicated combination of agronomical consolidation, modern solonetzization, and residual alkalinity. It is shown that the combination of physicomechanical and chemical properties (high content of physical clay and clay fraction, low portion of aggregate openness and high interaggregate porosity, the presence of exchangeable sodium in the soil adsorbing complex, alkaline reaction (pH 8.3), mobility of the clay-humus fraction, etc.) favor the formation of overcompacted plow and subplow horizons and their dynamic stability independently of regular mechanical cultivation.
Keywords: degradation of structure, ; subsurface compaction; Sodic features; Haplic Chernozem
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Coniferous leaf-bearing forest biomass assessment by the example of the educational and experimental soil and ecological center of Lomonosov Moscow State University «Chashnikovo»Moscow University Bulletin. Series 17. Soil science. 2024. 2. p.37-45read more440
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The aim of the work was to assess the contribution of the following components – biomass and mortmass of tree stands, undergrowth, living ground cover, and forest litter — to the total organic matter’s pool of plant community. The object of the study was a territory of coniferous-deciduous forest located in Solnechnogorsk City District of the Moscow region, in which five permanent sample trial plots of 50×50 m were allocated. The greatest contribution to the total organic matter mass of studied plant communities was made by forest stand perennial parts (up to 87%) and forest stand mortmass (up to 14%), and phytomass of deciduous trees in stand containing 32 to 98%, which was connected with incompleteness of forest restoration succession process. The contribution of forest litter was no more than 3%; litter deposit was low (0,18–1,21 kg×m-2), which is not typical for spruce forests, as is the fact that all litter is of the destructive type. Living ground cover in terms of floristic composition and ecological-coenotic structure was typical for the subzone of coniferous-deciduous forests; its contribution to the overall productivity of forest biogeocenosis was insignificant. The spatial intrabiogeocenotic structure of litter reserves and living ground cover biomass distribution was disturbed compared to typical spruce forests due to the high proportion of deciduous species in the forest stand. Deciduous species inclusion in the tree tier, typical of the final stage of formation of a secondary coniferous forest during succession, caused a slight increase in the intensity of the biological cycle, which was indicated in this case by a decrease in the supply of litter and a simplification of their structure. Since the biomass and mortmass of tree stand make the greatest contribution to the sequestration of carbon by forest biogeocenoses, it is these components that require the most detailed assessment during monitoring observations, the purpose of which is to assess the carbon reserves of terrestrial ecosystems.
Keywords: species composition; mortmass; ground cover; litter; permanent sample plots
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Microbial production and carbon dioxide emission by soils of the Chashnikovo carbon polygon with diff erent potential for mineralization of organic matterMoscow University Bulletin. Series 17. Soil science. 2024. 4. p.141-156Elizaveta N. Derevenets Svetlana. A. Klachkova Olga Iv. Manakova Yulia. L. Meshalkina Alexey S. Sorokinread more313
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Microbial production and CO2 emission in Albic Retisol (Loamic) and Albic Retisol (Aric, Loamic) of Lomonosov Moscow State University carbon polygon «Chashnikovo»≫ in the Moscow region were studied during the peak of vegetation activity. The object represents monitoring sites in two natural ecosystems (secondary spruce forest and mixed-grass meadow) and in two agroecosystems (perennial grasses and bare fallow). The soils differed in their stocks
of organic matter carbon (Corg), microbial carbon (Cmic), and potentially mineralizable carbon (Cpm). The highest values of microbial indicators and carbon content were observed in the upper 30 cm with a maximum in the upper 10 cm. Corg stocks in the 0–30 cm layer were 1.1–1.3 times higher in agricultural soils (72.7–75.6 t ha-1) compared to natural ones (59.4–65.0 tha-1). The contribution of Cmic stocks to Corg stocks in meadow soils and agricultural soils under perennial grasses (1.8 and 1.4%) was higher than in forest soils and soils under bare fallow. Сpm stocks in natural soils (1.34 and 0.97 tha-1 for a layer of 0–10 cm) were 1.3–2.3 times greater than in agricultural soils, but the intensity of mineralization of organic matter in agricultural soils was 1.4–2.9 times lower than in soils of natural ecosystems. For ecosystems with similar vegetation, the influence of Сpm stocks on the amount of microbial CO2 production was shown; its proportional increase was noted. Maximum potential microbial CO2 production (4.8 gCm-2day-1 for the 0–10 cm layer and 10.5 gCm-2day-1 for the 0–30 cm layer), Cmic stocks (0.50 tha-1), as well as CO2 emission (11.09±0.29 gCm-2day-1) were characteristic of the soils of a dry meadow. In other ecosystems, CO2 production by microorganisms was lower by approximately 2 times. Since CO2 emission, in addition to microbial respiration, is also caused by the respiration of plant roots, its minimum values were observed in agricultural soils under bare fallow (5.01±1.43 gCm-2・day-1). CO2 emission from forest soils and agricultural soils under perennial grasses was statistically not significantly lower compared to the meadow.Keywords: greenhouse gases; basal respiration; microbial biomass; potentially mineralizable organic matter; carbon stocks in soils
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