bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Pareiasaur (Parareptilia) from the Lower Vyatkian (Upper Permian) of Orenburg Region, Russia
Authors: Boyarinova E. I. , Golubev V. K.
Published: April 2024

A new genus and species, Senectosaurus karamzini gen. et sp. nov. was described based on remains of the postcranial skeleton of a large adult pareiasaur from the Lower Vyatkian of Preobrazhenka-2 locality (Orenburg Region). The new pareiasaur is characterized by large postcranial osteoderms of the platform type. Osteoderms are flattened, with flat ventral and slightly convex dorsal surfaces, with one to three contact facets from a toothed or scaly suture connection with neighboring osteoderms, without dorsal elevation and surrounding fossae circumcinctae and with numerous large fossae on the dorsal surface of the platform. The absence of dorsal elevation distinguishes the new pareiasaur from all known pareiasaurs with postcranial osteoderms.
To the fauna of fleas (Insecta, Siphonaptera) of the reserve “Baikalo-Lensky”
Authors: Berlov O. E , Artemyeva S. Yu.
Published: April 2024

The fauna of fleas of the Baikalo-Lensky State Nature Reserve (Siberian Federal District, Irkutsk Region) has been poorly studied. One of the authors previously published information about 7 species collected in the reserve, based on the materials of two field seasons in 1997 and 1998. As part of the inventory of the fauna of ectoparasites of the reserve, during seven field seasons, in 2016-2022, new material was collected. The purpose of the research is to make an inventory of the species composition of fleas that parasitize small mammals. As a result of the work, 384 fleas were caught. The collected fleas belong to 16 species from three families. The most interesting find is the flea Catallagia striata Scalon, 1950, which was first encountered in Irkutsk region.
Species of the genus xenopsylla (siphonaptera; pulicidae) as vectors of plague infection in its natural foci
Authors: Medvedev S. G. , Verzhutsky D. B. , Kotti B. K.
Published: April 2024

In the review, the peculiarities of distribution, host-parasite relations, and significance as vectors of plague of the fleas of the genus Xenopsylla (Pulicidae) are analyzed. Spatial distribution of plague foci all over the world and the role of this genus fleas in circulation of the plague pathogen in various regions of the planet are considered. It is shown that out of at least 255 existing natural foci of plague around the world in which the circulation of the pathogen occurs independently of the other foci, in 114 foci the only main vectors or members of the main vector pool are the fleas of the genus Xenopsylla . Among 21 flea species of this genus found naturally infected with the plague microbe in nature, 17 species are considered as main vectors of this pathogen in a given number of foci; in Africa and Southeast Asia, the role of the flea X. cheopis is the most significant.
Incomplete fragmentation of giant tegument nuclei in acanthocephalus tenuirostris (palaeacanthocephala, echinorhynchida)
Authors: Davydenko T. V. , Nikishin V. P.
Published: April 2024

The giant nuclei of the Acanthocephalus tenuirostris tegument at the late acanthella stage show incomplete fragmentation. This process is preceded by the transformation of the nuclei, and their acquisition of a tree-like shape. Thin connections between the nuclear fragments of the tegument is retained both at the stage of cystacanth and in the adult acanthocephalans. It is assumed that such an organization of the nuclear structure ensures the vital activity of the tegument, the volume of which increases repeatedly during the subsequent growth of the acanthocephalan.
On the expansion of the range of Polyplax hannswrangeli Eichler, 1952 (Anoplura) in Western Siberia
Authors: Starikov V. P. , Kravchenko V. N. , Vershinin E. A. , Volodina O. Yu.
Published: April 2024

In the South Trans-Ural region, 2106 insectivores and rodents of 18 species were captured in 2022, and 3633 lice of 9 species were collected from them. The louse P. hannswrangeli parasitizing on the field vole was recorded for the first time in this area. A total of 64 specimens of this louse species (adults and larvae) were recorded. The louse P. hannswrangeli was found on voles in two out of 22 examined biotopes in a pine-birch wild rose-forb felling and dead cover pine forest. At present, the louse P. hannswrangeli in the West Siberian Plain is known from forest-tundra, northern and middle taiga, and herb-bunchgrass steppe. Further studies do not exclude findings of this species in other zones (subzones) of Western Siberia.
Stages of Restoration of Components of Post-Agrogenic Pine Forest Ecosystems at the National Park “Smolensk Lakeland”
Authors: Shopina О. V. , Geraskina А. P. , Кuznetsova А. I. , Тikhonovа Е. V. , Тitovets А. V. , Bavshin I. М. , Khokhryakov V. R. , Semenkov I. N.
Published: April 2024

Rural depopulation in Russia was accompanied by the abandonment of arable lands and natural reforestation. The aim of the work was to study soils and phytocenoses of six stages of pine forest restoration on rocks with coarse granulometric composition in the north-west of Smolensk region. The research was carried out at 18 key sites, characterizing 6 stages in triplicates. Under agrocenoses and one-year-old fallow lands we found agrozemes (Arenosols (Aric)) with a thick arable layer and a minimum abundance and biomass of macrofauna, represented mainly by phytophages and saprophages. At the 2nd stage of fallow meadows, grey-humus soils (Arenosols) and sod-podzols postagrogenic (Entic Podzols) were found with unchanged morphological properties in comparison with the first stage. Here, the biomass of macrofauna is maximal due to intensive invasion of open biotopes by insects. Young (up to 30 years old) pine forests grew on similar to the Stage 2 regraded soils. During 10 years of a forest growth, litter and protohumus regrading horizons were formed. In middle-aged (70–80 years old) pine forests on sod-podburs post-agrogenic regraded (Entic Podzols), signs of an eluvial process are manifested. Macrofauna is characterized by a decrease in the biomass of a litter population. In forests older than 80 years, decay of pine stands with the formation of complex spruce forests have begun. In soils, even lower boundary of old-fallow horizon disappears without podzolic horizon formation. Here, the maximum biomass of litter macrofauna is revealed. The final stage is shrubby (lingonberry)-green-moss pine forests older than 90 years growing on podzols (Albic Podzols) with remains of old-fallow horizon. Among macrofauna, litter macrofauna prevail in terms of a biomass, but the biomass is lower than in the previous stage. Due to the different degree of morphological manifestation of the alfegumus process, the fifth and sixth stages can be considered as variants of the development of post-agrogenic soils under pine forests.
Agrogenic Soils on the Updated Version of the Soil Map of Russia, 1 : 2.5 M Scale: Classification Diversity and Place in the Soil Cover
Authors: Gerasimova M. I. , Ananko T. V. , Konyushkov D. E. , Savitskaya N. V.
Published: April 2024

Usually, soils changed by farming (agrogenic soils) are not shown on small-scale maps, including the Soil Map of the Russian Federation, 1 : 2.5 M scale (1988). One of the issues of the map updating performed by the Dokuchaev Soil Science Institute is the inclusion of agrogenic soils into the map contents and representation of some of the former native soils as agrogenic soils on the updated map. Preliminarily, all native soils shown on the map have been reclassified into the new Russian soil classification system. Agrogenic soils in this system are separated as agrosoils in different orders and as a specific order of agrozems. Agrogenic soils have been identified in the soil polygons in agreement with the map showing the percentage of arable land in Russia linked to the polygons of the soil map. We have identified the classification position of the initial native soils involved in arable farming. Overall, 114 legend units representing agrosoils and agrozems have been identified. This number is dictated by the diversity of native soils subjected to the agrogenic impact and their agrogenic modifications. Agrogenic soils on the updated map are shown in 4813 polygons out of the total of 25711 map polygons. Chernozems are characterized by the greatest diversity of agrosoils and the largest number of polygons containing various agrochernozems. The order of texture-differentiated soils is also rich in agrogenic soils, both agrosoils and agrozems. Arable soils initially belonging to the order of Al–Fe-humus soils are present in a relatively small number of polygons and are only represented by Al–Fe-humus agrozems. The number of polygons with participation of agrogenic soils and their proportion in the soil cover illustrate geographical patterns of their distribution, in particular, homogenous or mosaic distribution patterns in the areas of different soil orders.
Changing the Phosphate Regime of Soils in the Middle Taiga When Using Biochar
Authors: Dubrovina I. A.
Published: April 2024

The influence of wood biochar on the content of various forms of phosphates was studied in laboratory experiments on soils with different phosphorus availability. Soils of the middle taiga subzone of Karelia were used in this work: a sandy Umbric Podzol and a heavy loamy Umbric Retisol. The tests studied the effect of two fractions of biochar (3–5 and ≤2 mm) in an amount of 2% and 5% of soil mass on pHKCl, the content of available and total phosphorus, the inorganic phosphorus fractions (Chang-Jackson method), and the total phosphatase activity of soils, as well as the effect of separate and combined application of biochar and fertilizer (NPK) on the content of available phosphorus in a pot experiment with spring barley. The research revealed that biochar significantly increased the content of available phosphorus by 20–40%, increased the content of the fraction of Ca-bounded P, Al-bounded P and loosely-bounded P, and also increased the phosphatase activity in the Umbric Podzol. In pot experiment was noted a higher content of P2O5 in variants with biochar ≤2 mm, in variants with fertilizer, and a significant mutual influence factors of biochar and fertilizer. Biochar increased the content of available phosphorus by 2–6%, increased the content of Ca-bounded P and loosely-bounded P (with biochar ≤2 mm at 5% dosage), and had no significant effect on the phosphatase activity in the Umbric Retisol. Only combination of biochar ≤2 mm and fertilizer had a significant effect in pot experiment with Umbric Retisol. In general, the most noticeable effect on almost all studied indicators was provided by ≤2 mm fraction of biochar in a 5% dosage. The use of biochar led to statistically significant increase in pHKCl values, and did not affect the content of total phosphorus in both soils. Biochar had a greater effect on the phosphate regime of coarse-textured soil with an initially lower pH and a less content of available and total phosphorus.
Thermal Diffusivity of Peat-Sand Mixtures with Different Peat and Sand Contents
Authors: Arkhangelskaya T. A. , Telyatnikova E. V.
Published: April 2024

The thermal diffusivity of screened quarry sand with a predominance of a fraction of 0.05–0.25 mm, lowland packed peat, and their mixtures was studied. Sand was mixed with peat in various proportions; the content of peat in mixtures ranged from 1 to 80% by dry weight. Metal cylinders 10 cm high and 3.8 cm in diameter were filled with sand, peat, and peat-sand mixtures. The thermal diffusivity was measured in the laboratory using the unsteady-state method with a working temperature range of 20–26°C. The heating rate of the packed samples was measured after the samples were placed in a liquid thermostat with a constant water temperature. For each sample, a series of measurements was carried out with a step-by-step change in water content from the maximum one after capillary saturation of the sample to the minimum one, corresponding to the air-dry state. The thermal diffusivity vs. water content dependence was almost linear for peat, and for sand it was a curve with a maximum. The lowest thermal diffusivity was obtained for peat and mixtures with low sand contents; the highest one – for pure sand. Within the studied range of water contents, the thermal diffusivity of different samples changed by a factor of 1.3–2.8. The non-linear character of the thermal diffusivity vs. peat content dependence was discovered. Small additions of peat to sand resulted in a noticeable decrease in the thermal diffusivity of the mixture; small additions of sand to peat had practically no effect on thermal diffusivity. The thermal diffusivity of the studied substrates increased with increasing sample bulk density and sand content; decreased with increasing organic matter content.
Assessment of Changes in the Biological Activity of Mountain Meadow-Steppe Soils of Pastures of Different Stages of Digression in the Central Caucasus
Authors: Gedgafova F. V. , Gorobtsova O. N. , Uligova T. S. , Tsepkova N. L. , Khakunova E. M. , Daova K. Kh. , Tembotov R. Kh.
Published: April 2024

The indicators of biological activity (humus content and reserves, microbial biomass carbon content and reserves, activity of hydrolase and oxidoreductase class enzymes) in the upper horizons (0–10 cm) of mountain meadow-steppe soils of the Central Caucasus (Kabardino-Balkaria) were determined at different stages of pasture digression (D1, D2, D3). It was found that the values of controlled soil parameters in conditions of weakly (D1) and moderately disturbed (D2) meadow phytocenoses did not significantly differ (t 1.97; P 0.05). Statistically significant decreases (t 2.95; P 0.05) in biological parameters were revealed in soils of severely disturbed meadow steppes (D3) compared with less damaged meadows (D1 and D2). Based on the totality of the studied indicators of biological activity, an integral indicator of the ecological and biological state of soils (IIEBSS) is calculated, reflecting the overall level of biological activity of the studied soils at different stages of digression of meadow-steppe communities. There was a decrease in the IIEBSS of moderately grazed (D2) and overgrazed (D3) meadows relative to the values of the conditional standard (D1) by 11and 45%, respectively. The obtained results of the biological state of mountain meadow-steppe soils are used for monitoring studies aimed at assessing the degree of change in the soil and vegetation cover of mountain pasture ecosystems.
Quantitative Characteristics of the Microstructure of Typical Chernozems Using Different Agricultural Technologies
Authors: Yudin S. A. , Plotnikova O. O. , Belobrov V. P. , Lebedeva M. P. , Abrosimov K. N. , Ermolaev N. R.
Published: April 2024

The methodological possibilities of micromorphological soil research making it possible to analyze digital images of soil thin sections at a quantitative level are presented in this study. A new software Thixomet Pro has been tested for quantitative micromorphological study of sail on the example of soil thin sections from the surface horizons of Haplic Chernozem. Soil samples for preparing thin sections were collected on the territory of scientific and industrial field test plot for assessing the impact of agro technologies in grain crop rotation on soil properties (Kursk region, Russia). In the field test plot, conventional agro technology (real tillage) and no-till are compared. Soil sampling was carried out in two replications from depth of 10–15 cm. The analysis revealed the variability of microstructure of Haplic Chernozem in the size, shape and orientation of aggregates associated with the use of agricultural technologies with and without plowing in grain crop rotation. In the Сhernozem with no–till, aggregates are generally larger compared to the aggregates of Сhernozem with conventional agro technology. This is noted at all levels of comparison of direct seeding and conventional agricultural technology: in the minimum diameter, the fraction 1–2 mm prevails against 0.25–0.5 mm, respectively, in the average diameter, fractions 1–2, 2–3 and 3–5 mm prevail against 0.5–1 and 0.25–0.5 mm, respectively, in the maximum diameter, fractions 1–2, 2–3 and 3–5 mm prevail against 0.5–1, 0.25–0.5 and 1–2 mm, respectively. It is also shown that less rounded and isometric aggregates are formed during direct seeding. With direct seeding, the proportion of aggregates with a form factor of 0.2–0.4 is higher and the proportion of aggregates with a form factor of 0.4–0.6 is lower than with traditional technology. The proportion of subhorizontal aggregates in direct seeding is higher compared to traditional processing (54.3 and 34.1% respectively).
Plutonium Accumulation by Vegetation on Different Soils
Authors: Edomskaya M. A. , Lukashenko S. N. , Shupik A. A. , Shapovalov S. G.
Published: April 2024

The high variability of the plutonium transfer factors presented in the literature makes it relevant to study the mechanisms that affect its migration ability and its availability for vegetation. The variability of transfer factors is explained by different properties of soils, since the redox potential and soil acidity can significantly affect the mobility of plutonium. In the vegetation experiment, the migration of plutonium in the “soil-agricultural plant” system was studied for different types of soils. The content of 239 + 240Pu was analyzed by alpha spectrometry with preliminary radiochemical isolation. Plutonium migration parameters were determined using barley (Hordeum) and beans (Fabaceae) as test cultures. The plutonium accumulation coefficients obtained in the course of vegetation experiments are in the range of 3.1 × 10–4–6.8 × 10–3, with an average value of 3.8 × 10–3 for the aboveground part of barley and 9.2 × 10–3–7.6 × 10–2, with an average value of 3.8 × 10–2 – for the root system of barley. The transfer factor range was 1.5 × 10–3–5.7 × 10–3 with an average value of 3.7 × 10–3 and 5.8 × 10–2–6.5 × 10–2 with an average value of 6.2 × 10–2 for the aboveground part and the root system of the beans, respectively. It has been determined that the nature of the plutonium distribution over the vegetative organs of the crops under consideration is non-uniform. On average, the plutonium transfer factor for the aboveground part of plants is lower than for the root part by more than 40 times. It has been determined that the accumulation of plutonium in the aboveground parts of plants growing on different types of soil is not the same for individual species/organs of agricultural plants. For the aboveground part of the agricultural crops under consideration, the transfer factors differ up to several orders of magnitude. In general, the accumulation of plutonium by vegetation growing on different soils types is arranged in the following row: soddy-podzolic (Retisol) and gray forest soil (Phaeozem) lowland peat-bog (Histosol) \( \gg \) typical chernozem (Chernozem). The smallest accumulation of plutonium by vegetation is observed in soils with a high content of organic matter. For the root system of plants, the dependence of the plutonium accumulation coefficients on the soil type is uncertain.
Features of the Elemental Composition of Alluvial Soils of the Middle Course of the Bolshaya Kokshaga River
Authors: Isaev A. V. , Demakov Yu. P. , Sharafutdinov R. N.
Published: April 2024

The content of chemical elements in the alluvial soils (Fluvisols) of the middle reaches of the Bolshaya Kokshaga River, inheriting the composition from the lithological basis of two mineralogical-geochemical provinces of Central Russian and Priuralskaya, was estimated, which made it possible to establish the limits of the content of gross forms of elements and their background concentrations, to lay the foundation for monitoring the state of the environment on the territory of the Bolshaya Kokshaga Reserve. The content of 34 chemical elements was found in alluvial soils and sands of coastal shoals, of which the most common are Si, Al, Fe, Ca, K, Mg, Na, Ti, Mn, P, S with a content of 1 g/kg. The concentrations of many elements significantly differ by soil types, the greatest similarity was revealed between meadow and humus-gley. In comparison with alluvial soils, the sands of coastal shoals are characterized by a maximum content of Si and a minimum of all other elements. Turf soils are characterized by the lowest content of elements, with the exception of Si, meadow and humus-gley accumulate more Al, Fe, K, Na, Mg, Ti, Mn, Ba, Cr, Zn, Ni, V and As, silt-peat, which are highly mineralized peat deposits, accumulate more Ca, S, P, Sr, Cl and Rb. It was found that alluvial soils are characterized by a high natural level of content of As, Cu, V, P, Zr, Ni and Zn, exceeding the clarks (Kk = = 1.5–2), and low–Al, K, Mg, Ti, Sr, Rb, Na, Cl and Ca (Kk 1), the content of the remaining elements are comparable to Clark values.
The Litters and the Living Ground Cover as Informational Characteristics of Biogeocenoses for Moscow Oblast Small-Leaved Forests
Authors: Telesnina V. М. , Semenyuk O. V. , Bogatyrev L. G.
Published: April 2024

The ecological and coenotic structure of the living ground cover and the structural and functional features of forest litter for three types of forests were studied: hairy-sedge birch forest, birch-aspen hairy-sedge, soddy-pike birch forest, forming a sequential row as hydromorphism increases within the slope, gradually to the center of the drive-dividing depression. The ecological characteristic of the living ground cover is based on the grouping of ecological-coenotic formations according to A.A. Nitsenko and ecological scales L.G. Ramensky and H. Ellenberg. Increasing hydromorphism is accompanied by an increase in ecological and cenotic diversity. The total trophicity score also increases under conditions of increased hydromorphism – in the soddy pike birch forest – in combination with low Ellenberg acidity index. Conversely, the maximum scores for these indicators, with high variation, belong to the birch-aspen forest, which occupies intermediate positions in the series of increasing hydromorphism. It was established that the studied stands are characterized by destructive and fermentative litters. As hydromorphism increases, the litter deposit increases from 400 to 1400 g/m2 with a simultaneous increase of detritus part in L subhorizon. About 60% of total organic matter deposit concentrated the litter of small-leaved plantations is accounted by easily decomposing fractions. With a regular increasing ash content in the system of subhorizons L–F, the maximum ash content is obtained for detritus fraction of L subhorizon. With a regular increase in the ash content in the system of subhorizons L–F, the maximum ash content is characteristic of the detritus fraction of the subhorizon L. The parameters of the ecological characteristics underlying the method of principal components showed a good grouping of the studied phytocenoses according to the degree of moisture, especially when using the general properties of litter (stocks, thickness, detritus content). The expediency of using the properties of litter to establish the similarities and differences of the studied phytocenoses as characteristics that integrally reflect the characteristics of moisture is revealed. The parameters of the living ground cover in conjunction with a number of structural and functional features of forest litter are adequate indicators of the degree of hydromorphism.
Rhizosphere Effect and Bacterial Community Structure in Horizons of Podzolic Soil under Spruce Plants (Picea abies L.)
Authors: Yevdokimov I. V. , Semenov M. V. , Bykhovets S. S.
Published: April 2024

The relationships between the rhizosphere effects, allocation in soil horizons and bacterial community structure in the rhizosphere and the bulk soil of Retisol under spruce trees (Tver region, Russia) were studied. The rhizosphere factors (Rf) expressed as ratios of soil characteristics in the rhizosphere to that in the bulk soil were determined for the basic indices of microbial respiration, biomass and available nutrients pools in the top AEL (3–15 cm) and deep EL horizons (15–46 cm). The most prominent rhizosphere effects (Rf 1.6) were revealed for microbial biomass C, basal respiration, and SOM turnover rate. Rf value for the SOM turnover rate in humus AEL horizon was approximately 1.5, while in the EL horizon it reached 6. The Rhizosphere had higher microbial diversity, with a significant contribution of both Gram-positive and Gram-negative bacteria, including representatives of Acidobacteria, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Solibacteres and Spartobacteria. The Gram-positive orders Bacillales and Clostridiales predominated in the bulk soil, with the relative contributions of more than 80 and 50% for the AEL and EL horizons, respectively. Based on the number of microbial activity indices with high Rf values (three for the lower EL horizon and only one for the upper humus AEL horizon), the rhizosphere of the lower horizon is probably more pronounced “hot spot” of biological activity than that in the top soil layer.
Methane Emissions from Rice Fields of the Rostov Region
Authors: Gar’kusha D. N. , Fedorov Yu. A. , Tambieva N. S. , Mel’nikov E. V.
Published: April 2024

On the example of the Rostov region, the results of measurements by the chamber method of methane fluxes into the atmosphere from rice fields are analyzed. In addition to measuring methane fluxes in the phases of “germination” and “full ripeness” of rice, concentrations of methane and hydrogen sulfide, Eh, pH, density and humidity were determined in the water of the rice check and various horizons of watered soils. The rate of methane flow into the atmosphere from the surface of the rice check varied in the range from 0.195 to 0.531 mg СН4/(m2 h) and in the “full ripeness” phase of rice was on average 2.1 times higher than in the “germination” phase. The rate of methane flow into the atmosphere from the surface of soils located between rice checks was on average 4.9–12.1 times lower than the rate of its flow from rice checks, varying within 0.034–0.045 mg СН4/(m2 h). It is shown that after watering rice checks in soils isolated by a layer of water, Eh values decrease and, as a consequence, there is an increase in methane concentrations in soils and its fluxes into the atmosphere. According to the assessment, the total methane emission by rice fields of the Rostov region approximately reaches 1.253 tons per day or 150 tons/year, which is 0.4–1.5% of the annual methane release by the soils of the Rostov region.
Salinization and Solonetsization of Soils in River Valleys of the Kulunda Plain
Authors: Elizarov N. V. , Popov V. V. , Rybkina I. D. , Smolentsev B. A.
Published: April 2024

The surface of the Kulunda Plain is dissected by a system of ancient wide valleys, former runoff hollows, which have a very small slope (less than 1°). Rivers flow along these weakly expressed valleys, redistributing readily soluble salts throughout the territory. The regime of these rivers is characterized by a sharp and high flood wave and low (up to complete drying) runoff in the summer. The purpose of this work is to study the ion-salt system of soils of ancient runoff troughs of the Kulunda Plain, groundwater and river waters in order to identify modern processes of soil salinization. During floods, river water feeds close-lying groundwater, influencing its chemical composition. Studies of three key sites in the valleys of the Bagan (Novosibirsk region), Burla and Kulunda (Altai Territory) rivers took place in 2021–2022. Ground waters of varying degrees of mineralization (from 3.4 to 63.0 g/l) and lie close to the surface (2–5 m), which causes a wide distribution of saline hydromorphic soils in the study area. Differences in the salt state of soils in different valleys, groundwater and river waters are discussed. The degree of salinization of soils depended on their granulometric composition. The high content of physical clay contributed to the rise of salts with groundwater and their accumulation in the soil profile. A large amount of exchangeable sodium in the soil absorbing complex of the studied soils (more than 3–5 cm (eq)/kg), the predominance of easily soluble sodium salts in the soil solution with its low mineralization, as well as the alkaline reaction of the soil medium indicates the manifestation of the process of soil salinization.
Analysis of CO2 Emission by Urban Soils under the Conditions of the Kola North
Authors: Korneykova M. V. , Vasenev V. I. , Saltan N. V. , Slukovskaya M. V. , Soshina A. S. , Zavodskikh M. S. , Sotnikova Y. L. , Dolgikh A. V.
Published: April 2024

Dynamics in soil CO2 emission, temperature and moisture was observed during the vegetation season (from May to October) in 2021 and 2022 in the residential areas of Murmansk and Apatity cities (Murmansk region) in comparison with natural references. The average emissions from urban soils were 5–7 gC/(m2 day) in summer and 1–2 gC/(m2 day) in spring and autumn. Temperature was the main abiogenic factor that determined the seasonal dynamics of soil respiration (R2 from 0.4 to 0.7, p 0.05; temperature coefficient Q10 up to 2.5), while excess moisture had a limiting effect, especially in the natural areas. The heterogeneity of hydrothermal conditions and the content of biophilic elements determined the differences in the average CO2 emission between natural and urban soils. For the natural soils, the average temperature was lower and the humidity was higher than for urban areas, which determined the lowest emission values. Among urban sites, higher CO2 emissions have been shown for tree and shrub vegetation sites.
An Investigation of the Organic Carbon Stocks Estimates Uncertainty on a Fields Scale
Authors: Samsonova V. P. , Meshalkina J. L. , Dobrovolskaya V. A. , Kondrashkina M. I. , Dyadkina S. E. , Filippova O. I. , Krotov D. G. , Morozova T. M. , Krasilnikov P. V.
Published: April 2024

A study of the uncertainty sources in the assessment of organic carbon stocks in a layer of 0–30 cm at the scale of the sampling area (100 × 100 m) laid on soddy-podzolic cultivated soil (Albic Glossic Retisol (Aric, Loamic, Ochric)) was carried out. In the experiment, two sampling methods were used – the classic 10-cm layers from profiles and with an auger to the depth of 0–30 cm. The soil bulk density was determined by the Kachinsky method, the carbon content was determined by the Tyurin method. Some of the samples were additionally analyzed at the Bryansk State Agrarian University. The uncertainties associated with natural variation, sample preparation and the proper analytical process are estimated. The analytical uncertainty of the bulk density under the conditions of the experiment did not depend on the sampling depth and amounted to about 6%. The analytical uncertainty of Tyurin’s method did not differ in two laboratories. Its contribution was 5–9% of the total variation of the soil organic carbon content in the area. The uncertainty of sample preparation determined from 11 to 26%, natural variation – from 49 to 68% of the total variance, respectively. Determination of the carbon content in the samples taken by the auger, when the sample is taken immediately at 0–30 cm, wins in reducing intermediate operations and gives comparable results compared to layer-by-layer sampling. The uncertainty of sample preparation determined from 11 to 26%, natural variation – from 49 to 68% of the total variance, respectively. Determination of carbon content in samples taken by auger, when the sample is taken immediately at 0–30 cm, wins in reducing intermediate operations and gives comparable results compared to layer-by-layer soil sampling.
Kinetic Assessment of the Biodegradability of Gel-Forming Soil Conditioners in Incubation Experiments with Instrumental Monitoring of Carbon Dioxide
Authors: Smagin A. V. , Sadovnikova N. B. , Belyaeva E. A. , Korchagina K. V. , Kokoreva A. A. , Krivtsova V. N.
Published: April 2024

A quantitative study of the biodegradability of polymer soil conditioners is necessary for a reasonable prediction of their stability and functioning in soils. For this purpose, we proposed a new methodological approach based on PASCO (USA) equipment, which allows recording continuous kinetic curves of CO2 emission in laboratory experiments on incubation of composite gel-forming soil conditioners. Several characteristic types of respiratory curves have been identified and new physically based models have been proposed for their description with subsequent calculation of the half-lives of composite hydrogels. For the traditionally considered non-biodegradable acrylic superabsorbents of soil water, the possibility of rapid biodegradation was shown for the first time in the case of the introduction of a biologically active compost extract into their liquid phase. With this treatment, which brings laboratory experiments closer to real soil conditions, the half-lives of both the well-known Western superabsorbents Aquasorb and Zeba and the Russian hydrogels Aquapastus decreased by an order of magnitude from the initial values of 2–6 years to 0.1–0.3 years. In practice, this can negatively affect the profitability of using such materials for soil conditioning due to their rapid destruction and loss of functionality. The introduction of silver ions into innovative Aquapastus composite superabsorbents at a dose of 0.1% or 10 ppm in swollen gel structures effectively reduces their biodegradability, prolonging the half-life to 10 years or more, which is twice the German standard DüMV 05.12.12 for the stability of polymer meliorants.
About the Lack of Controllability in Models of “Naive Mechanics”. Three Exceptional Cases
Authors: Romanov I. V.
Published: April 2024

The problem of boundary controllability is considered for a wide class of models, which can be conditionally called “naive mechanics”. It is proved that for all models of “naive mechanics”, except for the three cases, there is no controllability to rest. All these three cases are classical examples of equations, two of which require additional study of the controllability property.
Forecast and Correction of the Orbital Motion of the Space Vehicle Using Regular Quaternion Equations and Their Solutions in the Kustaanheimo–Stiefels Variables and Isochronic Derivatives
Authors: Chelnokov Yu. N. , Sapunkov Ya. G. , Loginov M. Yu. , Schekutev A. F.
Published: April 2024

The regular quaternion equations of the orbital motion of a spacecraft (SC) proposed by us earlier in four-dimensional Kustaanheimo–Stiefel variables (KS-variables) are considered. These equations use as a new independent variable a variable related to real time by a differential relation (Sundman time transformation) containing the distance to the center of gravity. Various new regular quaternion equations in these variables and equations in regular quaternion osculating elements (slowly varying variables) are also constructed, in which the half generalized eccentric anomaly, widely used in celestial mechanics and space flight mechanics, is used as a new independent variable. Keplerian energy and time are used as additional variables in these equations. These equations are used to construct quaternion equations and relations in variations of KS-variables and their first derivatives and in variations of Keplerian energy and real time; the isochronous derivatives of the KS-variables and of their first derivatives and the matrix of isochronous derivatives for the elliptical Keplerian motion of the spacecraft are found, which are necessary for solving the problems of predicting and correcting its orbital motion. The results of a comparative study of the accuracy of the numerical integration of the Newtonian equations of the spatial restricted three-body problem (Earth, Moon, and spacecraft) in Cartesian coordinates and the regular quaternion equations of this problem in KS-variables are presented, which show that the accuracy of the numerical integration of regular quaternion equations is much higher (by several orders) of the accuracy of numerical integration of equations in Cartesian coordinates. This substantiates the expediency of using regular quaternion equations of the spacecraft orbital motion and the quaternion equations and relations in variations constructed in the article on their basis for the prediction and correction of the orbital motion of a spacecraft.
On Flexibility of a Sliding Vertical Support of a Flat Structure
Authors: Dosaev M. Z.
Published: April 2024

A flat body on hinged supports is considered. One of the supports is connected to the body by means of a slipping attachment. A flexibility of the support rods is modeled by a hinge with a helical spring of sufficient stiffness to prevent relative rotation. It is shown that the linearization of the equilibrium equations makes it impossible to estimate the equilibrium position. The equilibrium position is sought in the form of a series in terms of the reciprocal of the stiffness coefficient of the helical spring. It is shown that as the coefficient of stiffness of the helical spring tends to infinity, the moment of the helical spring, which models the internal bending forces in the rods, tends to infinity. For the case of vertical equilibrium, an estimate is given for a tangential reaction in the support hinge, which occurs when additional loads are introduced and in the case of small oscillations.
In all the cases considered, the reaction that occurs in the supports is much greater than the weight of the body.
Inverse Problems for the Equation of Vibrations of a Canister Beam to Find the Source
Authors: Fadeeva O. V.
Published: April 2024

For the beam vibration equation, inverse problems are studied to find the right side, i.e. vibration source. Solutions of the problems by methods of spectral analysis and Volterra integral equations are constructed explicitly as sums of series, and the corresponding uniqueness and existence theorems are proved. When substantiating the existence of a solution to the inverse problem by determining the factor of the right-hand side, which depends on the spatial coordinate, the problem of small denominators arises. In this regard, estimates of the denominators are established that guarantee their separation from zero, with an indication of the corresponding asymptotics. On the basis of these estimates, the convergence of the series in the class of regular solutions of the beam oscillation equation is substantiated.
Effect of Mean Pressure and Fixing Rigidity on the Bending of Cylindrical Shell
Authors: Ilgamov M. A.
Published: April 2024

The equation for the bending of a long cylindrical shell taking into account the static and dynamic pressures acting on both of its surfaces is given. Particular attention is paid to the role of boundary conditions and pressure, which is average between the static pressures acting on the surfaces. The compression of the wall in thickness is taken into account. The linear bending of a cylindrical panel with an arbitrary opening angle has been studied. The bending of a closed cylindrical shell is considered as a special case.
Regular Precession of a Gyrostat in Three Force Fields
Authors: Ol’shanskii V. Yu.
Published: April 2024

The article gives a solution to the problem of possible conditions of regular precession in the motion of a gyrostat around a fixed point under the action of two uniform and one inhomogeneous field. For the known case with equal precession and proper rotation velocities, new solutions are indicated with the precession axis deviated from the symmetry axis of the inhomogeneous field. New cases of regular precession are found, when the ratio of precession and proper rotation velocities is equal to two or one second. Application of the results to precession in orthogonal fields and to precession of a solid are considered.
Optimal Traction Control during High-Speed Maneuvering in Dry Friction Conditions
Authors: Reshmin S. A.
Published: April 2024

The problem of controlling the direction of the traction force during the motion of an inertial object is considered. The maximal possible value of the traction force is constant and is determined by the maximal dry friction force. At a finite time interval, the problem of bringing an object to a given rectilinear trajectory with simultaneous velocity maximization in the appropriate direction is considered.
Application of Multipole Decomposition for Sonic Boom Propagation Problems
Authors: Kornyakov A. A. , Soudakov V. G. , Shcheglov A. S.
Published: April 2024

In the present work a modification of the multipole decomposition method is developed, which makes it possible to relate the overpressure distribution in the near-field of a supersonic transport (SST) with a far-field distribution, which is needed for the solution of sonic boom propagation problem from SST. A generalization of the method for solving the integral equations arising from multipole decomposition is performed. An algorithm for multipole correction of near-field overpressure signatures obtained in numerical simulations has been developed and tested.
Self-sustained Oscillations and Limit Cycles in Rayleigh System with Cubic Return Force
Authors: Kumakshev S. A.
Published: April 2024

An oscillatory system with an excitation mechanism as in a Rayleigh oscillator, but with a nonlinear (cubic) returning force, is investigated. Using the accelerated convergence method and the continuation procedure for the parameter, limit cycles are constructed and the amplitudes and periods of self-oscillations are calculated. This is done for a wide range of feedback coefficient values, in which this coefficient is not asymptotically small or large. The proposed iterative procedure allows to achieve the specified accuracy of calculations. The analysis of the features of the limit cycle caused by an increase in the self-excitation coefficient is carried out. The results obtained are compared with the self-oscillations of a classical Rayleigh oscillator with a linear returning force.
On the Kinematic Description of the Motion of a Rigid Body
Authors: Petrov A. G.
Published: April 2024

A system of ordinary differential equations is derived for a vector of finite rotation corresponding to Euler’s theorem: the vector of finite rotation is directed along the axis of finite rotation of a solid and its length is equal to the angle of plane rotation around this axis. The system of equations is explicitly resolved with respect to the time derivative of the components of the rotation vector. The right part of the system depends on the rotation vector and the angular velocity vector in the main axes. The equivalence of the obtained system of equations to the system of equations for quaternions is shown. The coordinates of the orts of the main axes of a rigid body in fixed axes are expressed in terms of the angles of final rotation and the components of angular velocity according to simple analytical formulas.
On Integral Funnel of Control Systems, Changed at Several Small Time Interval
Authors: Ushakov V. N. , Ershov A. A. , Ushakov A. V.
Published: April 2024

A nonlinear control system in a finite-dimensional Euclidean space and on a finite time interval is considered, the dynamics of which changes significantly over several small sections from a given time interval. We study the degree of change in the reachable sets and integral funnels of the system under consideration when it varies in these sections. The corresponding changes are estimated in the Hausdorff metric.
Three-Dimensional Bending-Gravitational Waves in a Floating Ice Sheet from a Moving Source of Disturbances
Authors: Malenko Zh. V. , Yaroshenko A. A.
Published: April 2024

The ice cover is modeled by a thin elastic isotropic plate floating on the surface of a liquid of finite depth. The source of disturbances moves along the surface of the plate. The values of critical velocities at which the character of the wave disturbance changes are obtained. The angular zones in which the waves propagate are determined. The influence of the velocity of movement of the source of disturbances, the thickness of the ice plate, compression and stretching forces on the amplitudes of the waves formed is investigated.
Determination of 90sr in natural waters and water from observing wells at radioactive waste long-term storage and final disposal facilities
Authors: Voronina A. V. , Belokonova N. V.
Published: April 2024

The optimal conditions for pre-concentration of 90Sr from natural water samples by a T-3K carbonate-containing zirconium dioxide were determined. A method for determination of 90Sr in natural water samples was developed using the T-3K sorbent; the method provides as low detection limits as 0.03 Bq/L for 1L water samples and 0.02 Bq/L for 2L water samples. The method was tested on monitoring of 90Sr in natural water bodies at Sverdlovsk and Chelyabinsk regions as well as in waters of control and observation wells on the territory of a radioactive waste long-term storage facility. It was shown that the developed method can be used without control of strontium chemical yield in case of natural water samples containing up to 76 mg/L of Ca and 5.2 mmol/L of hardness salts taking into account the average strontium chemical yields of 91 ± 1% for 1L water samples and 81 ± 2%, for 2L water samples. In case of water samples with a higher hardness, the dependences of strontium yield on Ca concentration or hardness presented in this paper may be used for evaluation of strontium yield.
Extraction of actinides and lanthanides from nitric acid solutions with diphosphine dioxides in the presence of an ionic liquid
Authors: Turanov A. N , Karandashev V. K , Artyushin O. I , Brel V. K
Published: April 2024

The e ect of 1-butyl-3-methylimidazolium bis[(tri uoromethyl)sulfonyl]imide ionic liquid on the extraction of lanthanides(III), U(VI), and Th(IV) from nitric acid solutions with 1,2-bis(diphenylphosphinyl)ethane I and 1,2-bis(diphenylphosphinyl)benzene II has been studied. The stoichiometry of the extractable complexes was determined. A solution of dioxide II in dichloroethane extracts metal ions much more e ciently than a solution of dioxide I. It has been established that, in the presence of an ionic liquid in the organic phase, the e ciency of extraction of metal ions from nitric acid solutions with solutions of dioxide I increases signi cantly, while that of dioxide II decreases. As a result, in the presence of an ionic liquid in the organic phase, dioxide II is signi cantly inferior to dioxide I in terms of the e ciency of extraction of Ln(III), U(VI), and Th(IV) from nitric acid solutions, which is associated with a much higher ability of dioxide II to extract HTf2N.
Comparison of sorption characteristics of solid extractants based on tetraoctyldiglycolamide with respect to lutetium and ytterbium
Authors: Semenova N. A , Krasnikov L. V , Lumpov A. A , Sapozhnikova N. V , Zhukova O. L
Published: April 2024

The paper compares the sorption characteristics of solid extractants (extraction chromatographic resin (EXC)) based on tetraoctyldiglycolamide, DGA Resin (Triskem, France) and AXIONIT MND 40T (Russia), under static and dynamic conditions with respect to Lu and Yb. It was found that for AXIONIT MND 40T (EXC-TODGA), in contrast to DGA Resin (EXC-DGA), sorption equilibrium is attained much more slowly and signi cantly depends on the temperature and size of the extractant granules. The desorption of ytterbium and lutetium using various reagents was studied, and the solutions of DTPA and ammonium citrate were found to be the most e ective. The optimal conditions for concentration ytterbium and lutetium with the given solid extractants were determined and tested using real radioactive solutions.