Soil Temperature Regimes Research Articles

How different soil surface treatments in urban areas affect soil pore structure and associated soil properties and processes

Soil water and temperature regimes in urban environments are greatly affected by different surface treatments, and these may lead even to changes in soil properties. The goal of this study was to find out how soil properties had changed after 8 years of soil surface modification. Five surface treatment scenarios were considered: bare soil (BS), bark chips (BC), concrete paving (CP), mown grass (MG), and unmown grass (UG). X-ray computed tomography and micromorphological analyses showed that character of pores in soils with grass (MG, UG), which were mainly influenced by organisms living in soils and roots, differed from pore character in soil covers BC or CP, which mostly were impacted by organisms living in soils. Both groups differed from BS, which was predominantly affected by the regular treatment consisting in weed removal and soil loosening. Soil under BC was more compact than for other treatments due to decomposition of the bark chips mulch and migration of mulch components. Organic matter content was greatest but its quality lowest in the BC soil, followed by UG, MG, CP, and BS. The highest aggregate stability assessed using the water-stable aggregates (WSA) index was found for UG, followed by MG, BC, CP, and BS. The greatest water retention ability was observed for BC followed by UG, MG, CP, and BS. The unsaturated hydraulic conductivities for pressure head of –2 cm measured for UG, MG, and BS were much higher than were those for CP and BC. Finally, the greatest net CO2 efflux was measured for BC and MG, followed by UG, CP, and BS. CO2 emission correlated negatively with soil physical quality expressed as slope of the soil water retention curve at its inflection point. In general, the best soil conditions were observed for UG. No treatment considerably aggravated soil condition.

How do reactive aluminum and iron phases control soil organic carbon and phosphate adsorption capacity in agricultural topsoils across Japan?

ABSTRACT The growing number of studies suggests that the prediction of soil organic carbon (SOC) storage and persistence can be improved by accounting for variations in soil reactive metal phases. Nevertheless, the dataset on reactive metals is often limited at a national scale. In Japan, the phosphate adsorption coefficient (PAC) has been measured for agricultural soils nationwide. PAC is known to be strongly controlled by reactive metals, and hence, it can be used as a surrogate for reactive metal content. However, the relationships between SOC, reactive metals and PAC across a wide range of agricultural soils remain unclear. We thus examined these relationships using agricultural topsoils taken from 115 sites across Japan, covering two major soil great groups, Andosols and Lowland soils, as well as various land uses and soil temperature regimes (7.2–19.1°C). For the whole dataset, PAC was strongly correlated with oxalate-extractable metals (Alox + 0.5Feox: Metalox, r = 0.83) and moderately with pyrophosphate-extractable metals (Alp + 0.5Fep: Metalp, r = 0.68). These results suggest a stronger contribution of short-range-order (SRO) minerals to PAC as the former parameter reflects the content of both SRO minerals and organically complexed metals, while the latter reflects only that of organo-metal complexes. Moreover, Metalp was the best predictor of SOC contents in both Andosols (r = 0.79) and Lowland soils (r = 0.65). When only soils at near neutral soil pH range were considered, the exchangeable Ca content also co-varied with SOC in Lowland soils (n = 17). Of the two metallic elements, reactive Al phases better explained the variation of SOC and PAC in Andosols, whereas reactive Fe phases also showed similar explanatory power for PAC in Lowland soils. Our analyses also suggested that soil group (esp. erosion intensity) and land use likely impacted the SOC-Metalox relationship in Andosols, whereas environmental factors such as soil temperature and soil redox regime affected those relationships in Lowland soils. Overall, we showed that PAC is a useful surrogate for SRO minerals and organo-metal complexes and, with careful considerations of the environmental and pedogenic factors, it is potentially useful to estimate the amounts of SOC stabilized by reactive metal phases in agricultural soils across Japan.

English

The current study was conducted in growth chamber with the aims to examine the effect of different soil types and temperature regimes on quantitative and qualitative traits of saffron and to assess the agro-climatic suitability of selected sites of Poonch Division of Azad Jammu & Kashmir for field scale saffron cultivation. Soil from 07 sites was collected and processed for pot filling. A total of 63 plastic pots (21 for each temperature level i.e., 19, 26 and 32 oC), were filled with soils of each site and incubated separately in growth chambers. The pots were arranged under completely randomized design (CRD) replicated thrice. Results indicated that maximum number of flowers (1.35 per plant), flower fresh weight (29.03 mg per plant), stigma length (1.21 cm), stigma fresh weight (8.97 mg per plant) and stigma yield (8.60 mg per pot) was recorded for Khaigala site (loam textured soil) at 26 oC followed by Trarkhel (sandy loam textured soil) and Abbaspur (loam textured soil) sites. On an average, maximum 58.30 days were taken to initiate flowering in soil of Alisojal site (clay loam textured soil) with flowering period of 17.06 days. The maximum number of daughter corms (2.92 per plant), corm diameter (9.61 mm), corm weight (15.76 g per plant), corm yield (47.28 g per pot), picrocrocin (11.32%) and safranal (0.22%) content was again recorded for Khaigala site (at 26 oC). However, maximum crocin content (14.33%) was noted for Alisojal site (1831 m altitude). The Cluster and PC analyses revealed that Khaigala, Trarkhel and Abbaspur sites produced saffron of better quality and agro-climatically suitable for establishment of saffron. Further, the saffron grown on loam and sandy loam textured soils showed better performance compared to that of clay textured soils.

Organic carbon in Mollisols of the world − A review

Mollisols represent 29 % of agricultural land and they are considered to be one of the most fertile soils in the world. Here, we compare soil organic carbon (SOC) concentrations and pools of Mollisols for the globe, the USA and Poland, and review how differences are caused by climate, land use, and key environmental factors. Globally, the mean thickness of the A horizon in Mollisols is 50 cm. At 0–30 cm the mean SOC concentration is 2.3 %, SOC pool is 84 t ha−1, and clay content calculated at 0–50 cm soil depth is 21 %. Mollisols in the USA have an A horizon thickness of 36 cm and have a mean clay content of 27 % (0–50 cm). SOC concentrations are 2.0 and 1.7 % and SOC pools are 85 and 116 t ha−1 at 0–30 and 0–50 cm soil depth, respectively. Mollisols in Poland have SOC concentrations of 1.8 and 1.5 % at 0–30 and 0–50 cm soil depth, respectively, and lower clay content (17 %) at 0–50 cm depth. The SOC pool at 0–30 cm depth is 74 t ha−1 whereas it is 106 t ha−1 at 0–50 cm. At the global scale, the highest SOC concentrations and pools are in Mollisols from Eastern Europe (including Ukraine and Western Russia) and Asia, while the lowest SOC pools are found in Mollisols from South America. The Mollisols in Western and Central Europe and North America have similar SOC pools, although Mollisols in North America have higher SOC concentrations and lower A horizon thickness. Globally, the mean pH value of Mollisols is 7.1, and the pH is slightly lower in Mollisols of the USA (6.9 ± 0.9). The SOC concentrations and pools are strongly and positively correlated with clay content. Soil moisture and temperature regimes determine SOC concentration and pools in Mollisols, and higher SOC concentrations and pools are in Mollisols with frigid and frigid-cryic soil temperature regimes as well as aquic, xeric, and aridic soil moisture regimes. Mollisols under grassland have the largest SOC pools compared to those cultivated or under forest. The important environmental factors on SOC concentrations and pools in Mollisols worldwide are soil texture, land use, and soil temperature regime.

The differential expression of the P5CR and αTPS6 genes in cowpea plants increases tolerance to water-deficit and high temperatures

Plants exposed to adverse environmental conditions develop molecular mechanisms of adaptation and/or defense, the osmoprotectors, which function as compatible solutes and contribute to tolerance via prevention systems and protection against cellular damage caused by these abiotic stresses. This study aimed to identify and characterize the osmoprotectors proline and trehalose in cowpea plants cv. Carijó under controlled conditions of water-deficit and heat stress based on the IPCC scenario of 4.8 °C increase in temperature, evaluating their structure and function through computational methods, as well as gene expression by RT-qPCR. The experimental assays were carried out in growth chambers under controlled conditions with different levels of soil water availability, phenological phases and temperature regimes. From the in silico analyses, ten TPS genes and one P5CR gene were identified in Vigna unguiculata, and these were named according to their chromosomal location. The VuP5CR and VuTPS genes play roles in hormone pathway signaling and in the response to light and biotic and abiotic stresses. The genes P5CR (proline) and αTPS6 (trehalose) were induced with increased temperature and lower water availability in the vegetative phase of cowpeas. In addition, P5CR also showed induction with 50% water availability at high temperatures. In the pod filling phase, the P5CR and αTPS6 genes were repressed with water availability of 75%, while only the P5CR gene was induced when water availability was reduced to 25% under heat stress. P5CR and TPS6 genes were induced in cowpea cv. Carijó in response to associated abiotic stresses (water-deficit and high temperatures), which suggests their participation in the mechanisms of adaptation of the species in adverse environmental conditions.

Thermal conductivity of urban and artificial soils: methodological aspects and mathematical modeling

There are various methods for experimental determination of the thermal conductivity dependence on soil moisture and substrates. The influence of the sample structure (monolith, bulk sample), sample temperature, the method of installing the probe into the sample on the obtained readings of the TEMPOS device was studied and methodological recommendations were proposed. The dependence of thermal conductivity of soils bulk samples and substrates on moisture is shown. The spread of thermal conductivity values in the moisture range from hygroscopic to full moisture capacity for soddy-podzolic soil is 0.229–1.430 W/(m*K), for peat – 0.250–0.521 W/(m*K), for sand – 0.280–2.605 W/(m*K), for a mixture – 0.234–1.568 W/(m*K). ). The influence of properties such as density, particle size distribution, specific surface area, organic matter content, salinity affected thermal properties to a lesser extent. The established patterns can be used to calculate the temperature regime of soils in solving a number of applied problems related to the construction of special soil objects, for example, when creating urban soil structures. For this, it is necessary either to determine the thermal conductivity experimentally, or to calculate it, using the physical parameters of soils and substrates. The first method is labor-consuming, the second is less accurate. As an example, the equations available for work in the HYDRUS-1D (Chang–Horton and Campbell) model are used. These equations either overestimate the thermal conductivity in the area of high substrate humidity, or underestimate the thermal conductivity in the area of low substrate humidity (sand, loam, peat and a mixture based on them).

Coupled heat and water transfer in heterogeneous and deformable soils: Numerical model using mixed finite element method

We present a generic model framework for coupled heat and water transfer (CHWT) in deformable (non-rigid) soils with spatial variations of soil properties. The model backbone is a mixed finite element method (FEM), which solves the Philip and de Vries (1957) CHWT model and achieves conservation of mass and energy on both local and global scales. Spatial variations occur in soil hydraulic and thermal properties due to transient water content and temperature distributions. Based on the mixed FEM scheme, a gradient measure and a clustering model (“k-means”) are proposed to trace the regions with large spatial variations of soil properties, and an adaptive mesh refinement technique is developed to improve the spatial resolution and simulation accuracy. Deformation perturbates local soil topography and alters transient soil water and temperature regimes in the deformed regions. A quasi-static deformation model is presented, and the deformation effects are incorporated into the mixed FEM scheme. When external load exists, soil deformation is simulated with an updated Lagrangian formulation, and the local water content and temperature variations due to soil volume changes are also updated in the CHWT model. Numerical examples, including thermally induced soil water transfer and water infiltration, illustrate the model ability to provide plausible CHWT results, especially the refined solutions near the wetting fronts and the water content and temperature distributions when the soil is deformable. In conclusion, the proposed model framework provides an effective pipeline to incorporate and process the spatial variations of soil properties and soil deformation in CHWT simulations.

Solution of the Heat and Mass Transfer Problem for Soil Radiant Heating Conditions Using the Method of Finite Integral Fourier Transform

To achieve high agricultural yields, it is essential to predict the soil temperature and moisture regime, considering the heating technology employed. The research object is soil heated by a ceiling-mounted infrared emitter. The research subject encompasses one-dimensional unsteady fields of soil moisture content and temperature. The research goal is to forecast the soil temperature and moisture regime under radiant heating conditions. The research methods involve the analytical solution of heat and mass transfer differential equations using the method of finite integral Fourier transforms. Research results indicate that the top layer of milled peat, with an initial moisture content of 3.7 kg/kg, will reach a final moisture content of 1.0 kg/kg in approximately 6 hours during infrared drying. As a result of radiant heating, the soil temperature will rise from an initial 5 ℃ to a final 22.6 ℃ in approximately 3 hours. The analytical solution of the mass transfer differential equation can be utilized for theoretical studies of drying capillary-porous materials, such as determining the drying period or the thickness of the material layer that will dry to a specified final moisture content. The analytical solution of the heat transfer differential equation, accounting for both thermal conductivity and the Dufour effect, can be employed to manage the operation of the infrared radiation source, such as determining its operational and shutdown periods when the soil surface temperature reaches its maximum (critical) value. The mathematical solutions discussed in the article do not consider thermodiffusion processes in the soil layer (Soret effect), which presents a promising direction for further scientific research.

Solution of the Heat and Mass Transfer Problem for Soil Radiant Heating Conditions Using the Error Function

Achieving high yields of agricultural crops requires the ability to predict soil temperature and moisture regimes, taking into account soil heating technology. The object of study is soil heated by a ceiling infrared emitter. The subject of study is one-dimensional non-stationary fields of soil moisture content and temperature. The objective of the study is to predict soil temperature and moisture regimes under radiant heating conditions. Research methods: analytical methods for solving differential equations of heat and mass transfer using the error function. Research results: the top 5 mm layer of milled peat with an initial moisture content of 3.7 kg/kg will reach a final moisture content of 1.0 kg/kg in about 6 hours during infrared drying. As a result of radiant heating, the soil will heat up from an initial temperature of 5 ℃ to a final temperature of 20 ℃ in approximately 3 hours. The analytical solution of the mass transfer differential equation can be used for theoretical studies of drying of capillary-porous materials, for example, to determine the drying period or the thickness of the material layer that will dry to a given final moisture content. The analytical solution of the heat transfer differential equation can be used to control the operating mode of the infrared radiation source, for example, to determine the periods of its operation and switching off in case the soil surface temperature reaches the maximum (critical) value. The mathematical solutions considered in the article do not take into account the cross processes of heat and mass transfer, which is a promising direction for further scientific research.

Сartographic models of soil temperature fields in the steppe battles of Khakassia and Tuva based on joint analysis of temperature monitoring ground and satellite data

The aim of the study was to justify the possibility of using quantitative characteristics of the temperature regime of soils obtained by a joint analysis of ground-based and satellite monitoring to create cartographic models of typological units of soil-bioclimatic zonation of the Khakassia and Tuva steppe basins. Location and time of the study. The development of methodology for identifying the temperature fields boundaries was carried out in 2019-2022, using as a case example the soil cover typological units in the Altai-Sayan region, including the diversity of steppes of the Chulym-Yenisei and Minusinsk troughs, the Turan-Uyuk, Central Tuva, and Ubsu-Nur basins. Key areas were selected taking into account the principles of landscape zoning, which make it possible to recognize, classify and map landscape-differentiating factors, landscape components, the regional landscape structure in their entirety and its dynamic features. Methods. Ground-based automated monitoring of air and soil was performed using specialized temperature recorders DS-1921G “Thermochron”, taking into account indicators reflecting the genetic unity of climate types in the Altai-Sayan region. To carry out retrospective analysis, statistical processing and visualization of MODIS data, a software and algorithmic toolkit created by the Institute of Computational Technology of the Siberian Branch of the Russian Academy of Sciences (Novosibirsk) was used: the software is based on a new technology for accessing the satellite data archive, implemented using the PostgreSQL DBMS with an additional module, designed for direct access to the file data archive without the need to first copy and convert the data format for the DBMS. Results. Based on a joint analysis of quantitative indicators of the air and soil temperature regimes, obtained using ground-based automated measuring systems and satellite data, a series of cartographic models were constructed: the latter reflect the temperature fields characteristics of typological units of soil-bioclimatic zoning of the Altai-Sayan region. The interpretation of the identification of typological units of the soil cover structure performed on the basis of a statistical analysis of the combination of boundaries and information content of the contours of the soil cover and the boundaries of temperature fields (day and night temperatures, as well as the difference in temperatures of two compiled series, calculated over a 16-year period). The novelty of the approach is based on the fact that cartographic models of temperature fields, constructed on the basis of quantitative temperature indicators, have information content sufficient for establishing relationships between the temperature regime and other characteristics of natural environmental objects, contributing to solving the problem of identifying and typologizing soil-ecological boundaries. Conclusions. Cartographic models of temperature fields obtained as a result of a joint analysis of ground-based and satellite data are sufficiently informative regarding the energy of soil-forming processes and can be used to assess soil thermal conditions in the inaccessible and hence poorly studied areas of the Altai-Sayan region.

Статистические характеристики данных температурного мониторинга грунтовых оснований фундаментов зданий города Салехарда за 2018–2023 годы как основа для автоматизации процесса первичной обработки данных

The Arctic today is a dynamically developing territory where the construction and operation of infrastructure are complicated by the presence of permafrost. Climatic changes and anthropogenic factors have a negative impact on their condition. In this regard, studies of the current and forecast state of permafrost in natural and anthropogenic conditions are relevant, which is necessary for the formation of plans for adaptation to climate change, design and engineering surveys work, and risk ma­nagement. Monitoring the temperature regime of soils at the base of the existing infrastructure seems to be the most obvious solution for monitoring the state of permafrost. The object of the study is the soil foundation of buildings erected on permafrost. The subject of the study is data obtained using an automated soil temperature control system for the foundations of capital construction facilities in Salekhard. For the purpose of identifying negative changes in the bearing capacity of permafrost at early stages, the task of determining a set of criteria based on the analysis of temperature monitoring data and their statistical characteristics is solved. In Salekhard wells were drilled at the base of 30 buildings to the depth of the foundation, where thermometric equipment was installed. The sensors measure the soil temperature every 3 hours and transmit it to the server for analysis. As a result, the possibility of using the amplitude of annual fluctuations in the temperature of the soil base and the capacity of the seasonal melt layer under the building to assess the effectiveness of the soil thermal stabilization system is shown. By analyzing the average and maximum temperature values in the bases of objects, it is possible to identify objects with weakened zones. A set of criteria is given for identifying objects with negative changes in the frozen base, and statistical characteristics can serve as a basis for automating the process of processing monitoring data. The information obtained on the parameters of permafrost under buildings will allow us to determine the current state of the soil foundations and predict the development of the situation in order to prevent the destruction of infrastructure.

ВЛИЯНИЕ КЛИМАТИЧЕСКИХ ИЗМЕНЕНИЙ НА РАСПРОСТРАНЕНИЕ БАКТЕРИАЛЬНОЙ ВОДЯНКИ БЕРЕЗЫ

An urgent problem for Russia and neighboring countries, which many associate with climate change, isthe spread of infectious diseases of the stand, in particular bacterial wetwood of birch. Woody vegetation is also significantly affected by soil temperature. The effectiveness of using remote methods for constructing temperature maps hasbeen proven by many studies.The article presents an approach to the construction of the surface soil temperature regime maps on the basis ofground-based research data and decryption of thermal channels of Landsat satellite images. Based on the observation dataof 2020-2022, the conversion coefficients of the Earth’s surface temperature into soil temperatures were determined.Landsat 5 and Landsat 8-9 images for the period 2009-2022 were used to construct maps of temperature distribution inthe surface soil layer in the Yangan-Tau UNESCO Global Geopark during the snowless period (from May to October).According to the data of the Duvan weather station, the trend toward climate aridification is characteristic of theterritory of the Yangan-Tau Geopark.40% of forests in the territory of the Yangan-Tau Geopark is occupied by birch, the loss of which will lead to adecrease in the territory’s aesthetics and will reduce the integrity of the forest and forest-steppe ecosystems. Thus, thestudy on bacterial wetwood spread in birch appears to be extremely relevant.In field studies, as well as by visual interpretation, 12 foci of bacterial wetwood of birch were identified on theterritory of the geopark.Comparison of the birch bacterial wetwood foci locations with the surface soil temperature regime distributionmap in the snowless season showed the predominant location of infected trees in an area with an average temperature of9.6 °C, while sound birch forests mainly grow in areas with an average temperature of 7.6 °C.Comparison of the infected birch stand distribution sites with the surface slope and NDWI did not reveal anyspecific features.The exposure assessment showed a frequent location of birch bacterial wetwood foci on the southeastern slopes.

Континентальность климата и теплообеспеченность почв степных склонов в верховьях Индигирки и Колымы

Steppe biotopes on the southern slopes of the Indigirka and Kolyma headwaters, judging by vegetation and invertebrate population, are analogous to South Siberiaвs mountain steppes. At the same time, the area of steppe slopes and the number of steppe plant and animal species decrease from the Indigirka to the Kolyma. Climate continentality decreases in the same direction, which permits to consider it the main factor impacting the distribution of thermophytic steppes in Northeast Asia. Measurements of temperatures in thermophytic steppe soils in the named river basins revealed no soil heat supply differences related to climate continentality. Comparison of the measurement results with long-term observation data on xeromorphic biotopes of southern slopes in the upper reaches of the Kolyma River permitted to extend this conclusion to the soils of all open dry southern slopes in the headwaters of the Kolyma and Indigirka rivers. Thus, the role of climate continentality and summer soil temperature regime in the long-term preservation of "islands" with a large number steppe species of plant and animal surrounded by permafrost mountain-taiga ecosystems in the upper reaches of the Indigirca River is questioned. It is shown that restrictions in the spatial distribution of some steppe invertebrate species are not determined by differences in the summer temperature regime of soil in the headwaters of the Indigirka and Kolyma Rivers, either.

Soil temperature regimes on the southern border of the zone of frozen bogs in Western Siberia

Numto Nature Park (Western Siberia) is one of the southernmost locations of frozen peatlands. In 2019–2022, soil temperatures were measured there using an automatic monitoring system. The measurements were carried out for Murshik Hemic Cryic Histosol on flat palsa peatlands and frost mounds. The temperature for Folic Albic Podzol was measured for reference. The average annual temperature of the soil surface was found to be positive in all study areas: + 0.8 °C on the frost mound; +1.3 °C on the flat palsa peatlands; and + 4.5 °C in Folic Albic Podzol. The low temperature on the frost mound is due to the low snow cover, so the soil surface cools down to the minimum in winter. As for flat palsa peatlands, peat remains frozen all year round, starting from a depth of 0.5 m. On the frost mound, at the same time, the depth of seasonal thawing is 2 m. In winter, the frost penetration on the mound doesn't reach the permafrost table, revealing its probable degradation in case of further climate warming. According to the soil thermal regime classification, the soil on the frost mound falls into the category of long-term seasonally frozen soils, while high palsa peatlands nearby Nadym Town belong to the permafrost type. Data from the nearby meteorological station show a trend of rising air temperature and rainfall. An analysis of the soil temperature regime and the course of exogenous processes demonstrate that Murshik Hemic Cryic Histosol on high palsa peatlands is unstable. Permafrost persists there due to the low thickness of the snow cover on the peaks, which facilitates winter cooling. If the snow-cover height increases, permafrost is likely to melt there.

Calculation of the temperature condition of a thermostabilizable base with a single pile

The article deals with one of the main problems of construction in the area of permafrost soils - the presence of sites represented by thawed permafrost soils [1-3], formed due to natural conditions (waterlogged site, site relief features, swamping, etc.) and man-made impacts (warming effect of buildings and structures, systematic discharges and leaks from engineering networks, runoff and stagnation of surface rainwater, etc.). To ensure the bearing capacity of a single pile and the specified temperature regime of the foundation soils in the given engineering-geocryological conditions, it is possible to use the cooling devices of seasonal action. The main issue when using the cooling devices of seasonal action is to determine the main parameters affecting the bearing capacity of a single pile and the deformability of the foundation. To determine the parameters affecting the bearing capacity of a single pile and the deformability of the foundation, a set of numerical temperature calculations of thermostabilized soil mass represented by thawed permafrost soils with a single pile under different initial boundary conditions was performed in the certified Frost 3D software package. Temperature calculations were performed for the thawed soil mass, in which a single reinforced concrete pile with a single vertical vapor-liquid thermal stabilizer structure is submerged. The geometrical dimensions of the calculated area are 30 × 30 × 30 m. Based on the results of numerical experiments, the main physical, thermal and geometric parameters of the formed frozen core have been determined, which will be incorporated into the methodology for predicting the bearing capacity of a single pile in a thermally stabilized viscoelastic foundation represented by thawed permafrost soils. On the basis of the calculations performed, a design diagram of a single pile in a thermostabilized foundation was built and graphical dependences of changes in the diameter, height and geometric position of the frozen core depending on the initial boundary conditions were plotted.

Soil Formation Features in Drained Lake Basins of the Bolshezemelskaya Tundra

The features of the structure, properties, and temperature regimes of soils functioning in two different drained lake basins of the Bolshezemelskaya tundra are characterized. The basins differ significantly in the features of landscape development, the composition of bottom (soil-forming) sediments, and the patterns of the soil and vegetation cover. In a naturally drained basin composed of mineral (sandy and clayey) bottom sediments, soils belonging to the departments Gley, and Poorly developed are formed, which are typical for the watershed landscapes of the region. Soils function as ecosystem-modified permafrost-affected profiles, partially protected from thaw. The soil profile is acidic, not saturated with bases, with moderate carbon content in the mineral horizons. In the artificially drained basin, covered with a layer of silted peat, predominantly peaty permafrost-affected soils were formed, including peat soils of tundra meadows, which are unique for the landscapes of the Bolshezemelskaya tundra. Peaty soils of the basin appear to be as ecosystem-protected, i.e. protected from thawing, and they are characterized by high ash content and slightly acidic reaction. A significant differentiation of the studied soil parameters are determined by different basins, which are different according to the composition of parent sediments, the specifics of landscape development, and manifestations of present-day cryogenic processes.

The content of phenols and activity of polyphenol oxidase in the hametophyte of dominant mosses in forest ecosystems of the Ukrainian Roztochia

Bryophytes are indicators of the state of forest ecosystems. Dominant species of forest mosses are sensitive to the influence of abiotic factors and demonstrate adaptive reactions different from vascular plants, which are decisive for the prediction of changes in the natural environment. We have analyzed the changes in the content of water-soluble phenols and the activity of polyphenol oxidase n the hametophyte of dominant epigean forest mosses depending on changes in the intensity of insolation, the water and temperature regime of soils and air in experimental localities of forest ecosystems of the Ukrainian Roztochia. The highest content of water-soluble phenolic compounds was found in the resistant mosses Polytrichum formosum and Atrichum undulatum on the territory of protected beech forest under conditions of low light intensity and sufficient humidity of local vegetation. The maximum indicators of the content of phenolic compounds were found in A. undulatum (199.5±9.8 μg/g of dry matter mass), and the lowest – in Plagiomnium affine (54.7±2.6 μg/g of dry matter mass) that is sensitive to changes in the ecological conditions of local vegetation in all studied areas. A significant decrease in the content of phenolic compounds in areas of disturbed ecosystems may indicate the active participation of phenols in the adaptation of mosses to the effects of high light intensity, elevated temperatures and moisture deficit. The highest indicators of polyphenol oxidase activity were determined in P. affine (120.4±6.1 relative units/g of dry matter mass*s) and P. formosum (41.8±2.1 relative units/g of dry matter mass*s) from local vegetation under unfavorable conditions on the territory of stationary recreation. A direct correlation between the content of phenolic compounds and the activity of polyphenol oxidase was not established. The higher activity of this enzyme under conditions of high light intensity than in shaded local plants may indicate a relationship between polyphenol oxidase and photosynthesis. An increase in the activity of polyphenol oxidase contributes to the significant formation of quinones, which, accumulating in cell walls, reduce the processes of lipid peroxidation, regulate their permeability and ensure better moisture storage in the moss turfs.

Factors controlling available soil nitrogen in Japanese paddy fields

ABSTRACT Available soil nitrogen (Av-N) is an important indicator for understanding the soil fertility in paddy fields. Previous studies have reported a decline in Av-N resulting from paddy-upland rotation at a regional scale in Japan, while the factors influencing this phenomenon on a national scale are not well understood. This study aims to assess the effects of soil temperature, land use, soil type and soil texture on Av-N in paddy fields across Japan. Soil surveys were conducted in 13 prefectures in 2020 and 2021, involving the collection of soil samples from the plow layer in a total of 2,600 paddy fields. Our results revealed that soil temperature had the most significant influence on Av-N, followed by land use and soil type. Av-N exhibited a negative correlation with soil temperature, whereby the average Av-N in the thermic soil temperature regime (>15°C, Av-N: 107 ± 48 mg kg−1) significantly lower than that in the mesic soil temperature regime (≤15°C, Av-N: 166 ± 74 mg kg−1). Increased upland frequency in paddy fields led to a decrease in Av-N, particularly pronounced in the thermic soil temperature regime, while partially mitigated in the mesic soil temperature regime. In the thermic soil temperature regime, paddy fields with long-term upland usage (upland frequency of paddy fields was more than 50%) had an average Av-N of 50 mg kg−1, necessitating additional organic matter application. Furthermore, the results concerning soil type and soil texture indicated that Av-N was higher in wet soil compared to semi-wet soil, and fine-textured soil had higher Av-N than medium-course textured soil. These findings underscore the negative effect of accelerated drying in paddy fields due to the expanding practice of paddy-upland rotation, leading to decreased Av-N. In conclusion, our study proposes the importance of organic matter management practices, with a primary emphasis on soil temperature, further refined by considering land use and soil type, to ensure the maintenance of adequate Av-N levels in paddy fields in Japan.

Long-term variability of the thermal state in the upper horizons of the cryolithozone in Central Yakutia

The results of the 42-year monitoring of the thermal state of permafrost landscapes in modern climate warming conditions at the “Chabyda” observation station (Central Yakutia) are presented. We studied the evolution of the variability of soil thermal state parameters: the temperature of soils on the sole of the seasonally shallow layer and in the layer of annual heat rotations, and the depth of seasonal thawing. The long-term variability of the average annual soil temperature, experiencing significant interannual and short-term fluctuations, has a multidirectional trend, with warming dominating. The main factors regulating the thermal state of permafrost landscapes are the short-period fluctuations in the snow accumulation regime. Despite significant interannual fluctuations, the depth of seasonal thawing responded to climate warming with multidirectional trends, and its increase or decrease was statistically insignificant. We performed a statistical analysis of the observation time series revealing correlations between climate elements (air temperature, total precipitation, average winter snow depth, duration of winter and summer seasons) and relationships between soil temperature regime parameters (Тξ, Т0, ξ) with climate elements. The results of these studies on the thermal state of soils can be applied to homogeneous landscapes in this region. They can also be used to model heat transfer processes in natural landscapes and develop hybrid intelligence methods for diagnosing the state of infrastructure facilities in the Far North based on high-performance computing systems.

Detailed soil mapping and classification study for sustainable agricultural land management; Samsun-Vezirköprü example

This study aims to determine basic physico-chemical soil properties, make a classification, create a soil database, and generate a digital soil map for agricultural areas that cover about 111 km2 ha and includes 18 villages located in Vezirköprü district in the Samsun province. The average annual temperature is 12.52 °C and the annual average rainfall is 518 mm. According to the Newhall simulation model, soil temperature and moisture regimes are Mesic and Typic Xeric, respectively. Field observations and investigation of topographical, geological, and geomorphological maps, 16 soil pedons were described. Soil samples were taken from each pedon based on the genetic horizon and laboratory analyzes were performed. The detailed field study was carried out by considering the grid method and auger examination. The determination and description of 16 soil series were made by evaluating the findings of analyses and field research. Due to their quick pedological processes, six of them were classified as Entisol, six as Inceptisol, three as Verisol, and one as Alfisol. Vertisols cover about 35.63% of the total area followed by Inceptisols at 22.3%, Entisols at 22.3%, and Alfisol at 13.58%. As for FAO-WRB classification system, soils were classified as Vertisol, Cambisol, Leptosol, and Luvisol. In addition, whereas the Bakçekonak series has the largest area (15.02%), the Yürükçal series was determined as the smallest land (1.65%) in the study area.