Granulometric Composition Of Soil Research Articles

Experimental assessment of strength characteristics of anthropogenic soils in a given mining area for justification of tractor propulsion type

BACKGROUND: In mining, there is a need to develop tractors as special robotic vehicles of the robotic mining facility that can efficiently move and work on soils with low bearing capacity, in waterlogged areas and in the underwater position. A preliminary evaluation of the strength characteristics of such a heterogeneous surface of the exploitation area helps to choose an effective concept and technical characteristics of the propulsor of the tractor. AIM: Formation of the database of the physical condition and mechanical properties of the environment in which the tractor will move and operate. METHODS: In order to achieve the aim, preliminary experiments were conducted on the terrain. Typical kinds of soil sites and watered areas, including those of anthropogenic origin, of a given mining area were identified. Full-scale instrumental tests were conducted to determine: granulometric composition of soils; physical and mechanical parameters of these soils at the selected sites using the developed original types of a penetrometer and a shear rig. RESULTS: The database of numerical values of measured strength characteristics of one of the soil types (as an example) as a possible supporting surface for vehicle motion in the area of mining facility operation is presented in a graphical form. The basis of this database is the graphs according to the results of experiments on free settlement and shear with the help of dies of two types of configuration (the round die and the original caterpillar track respectively); the granulometric composition of the selected soils has been evaluated. CONCLUSION: The methodology of preliminary assessment of the soil condition by two indicators of soil strength (the rut depth z depending on the average pressure under the die) and shear (average tangential stresses τ in the contact patch on the motion of the die relative to the soil, depending on the ratio of the normal force and the traction force in the contact plane) has been developed. The 3D model of the coastal and bottom area of the technogenic mining zone has been developed. Design variants of highly efficient types of tractor propulsors are selected on the basis of prediction of maximum allowable stresses in the contact patch with the ground for the bearing surface areas of the considered area of operation.

Density of soil composite composition in a changing magnetic field

The advancement of technical means for determining soil density in precision (controlled) agriculture necessitates the enhancement of non-destructive flow interaction methods. There is also a need to improve methods for assessing soil density, as existing deviations from optimal values adversely affect the yield of agricultural crops. This research aims to establish the density of the composites in the granulometric composition of soil by determining the self-induction voltage in a changing magnetic field. The research methods are adapted to determine the relationships of Larmor precession under variable inductive current for the density of each composite in the granulometric soil composition. Experimental investigations were conducted by measuring the self-induction voltage of a solenoid acting as a sensor for each of the composites located within the core. The processing of experimental results was carried out according to the principles of mathematical statistics and probability theory, using approximations in the Excel and Statistica software packages. Based on the results of the experimental investigations, models of the relationships between the density ρ (1.0-1.5 g/cm3) of soil composites and the self-induction voltage eL=184-192 mV, with a generator voltage of 5 V and determination coefficients R2=0.95-0.99, have been established. These models enable the assessment of soil density with high accuracy, thereby facilitating the optimisation of agronomic processes. It has been determined that these models can be used with a high degree of reliability as calibration characteristics for the design of technical means for flow-based non-destructive measurement of the density of the main soil types in Ukraine. Furthermore, it has been identified that future research should focus on a more in-depth investigation of the relationships between magnetic permeability and the agrophysical characteristics of soil within the locally defined inductive field of the sensor (solenoid). An applied aspect of the obtained results is the further development of adaptive machinery and monitoring systems for soil conditions, aimed at achieving optimal cultivation indicators, as well as their utilisation by research institutions and instrument-making enterprises

Влияние осадков сточных вод на тест-растения и агрохимические свойства почв

Purpose: to assess the fertilizing value of sewage sludge. Materials and methods. The material used for research was sewage sludge from municipal wastewater treatment plants in Novocherkassk with a three-year stay period on the sludge map. The research was carried out as a part of a vegetation experiment on soils selected from agricultural lands in Aksai district Rostov region. According to the analysis, the soils are non-degraded, non-saline with a low humus content and an average nutrient content. The granulometric composition of soils is dominated by coarse silt fractions. Sewage sludge, on the contrary, is characterized by a high content of organic matter and nutrients; sand fractions predominate in the granulometric composition. Radish and watercress were used as test plants as they were the most sensitive to the presence of contaminants. Soil bioproductivity was assessed by seed germination, total biomass, and average biomass per plant. Results and discussions. The best germination of plant seeds was noted in variants with the application of sewage sludge to soils in comparison with both the control and the variant of using fertilizers in similar doses of the active substance. Under the influence of sewage sludge, changes in the qualitative composition of soils were noted: the amount of nitrates, phosphates, calcium ions and sulfates increased, and the content of organic matter increased. Conclusions. The positive effect of sewage sludge on plants has been determined: the radish yield increased by 55 % with the use of sewage sludge, and by only 10 % with the use of azofoska (nitrogen-phosphorus potassium fertilizer); the watercress yield increased by 29 % against the background of the use of sewage sludge and by 2 % against the background of the use of azofoska. In variants with the application of sewage sludge, an increase in the content of organic matter by an average of 30 % is observed. In soil samples with sewage sludge, an increase in the nitrogen content by 30–59 %, phosphorus by 67–78 % compared to the control was noted, and when azofoska was added, in comparison with control samples, the amount of nitrogen increased by 5–23 %, and phosphorus by on average by 50 %.

Metrological characteristic of the pipette method (GOST 12536-2014) for determining soil granulometric composition

The aim of the study. To calculate precision indicators (repeatability and reproducibility) and uncertainty in determining the granulometric (grain) composition of soils using the pipette method. Methods. Using the pipette method the content of the following granulometric fractions was determined in soil samples: 0,1–0,05 mm, 0,05–0,01 mm, 0,01–0,005 mm, 0,005–0,002 mm, 0,002–0,001 mm, less than 0,01 mm, less than 0,001 mm. The determination of pH of the salt extract was carried out by potentiometric technique, and organic matter was measured photometrically. For each aliquot of the sample 16 single measurements were obtained for each soil fraction. Based on these data, precision indicators were assessed under conditions of intra-laboratory repeatability and reproducibility, uncertainty indicators were assessed as well. Main results. The following intralaboratory quality indicators were obtained for the method of determining the granulometric (grain) composition of soils using the pipette method: 1) The value of the intralaboratory repeatability indicator of analysis results (σr) ranged 0,4–1,8%. 2) The relative indicator of intralaboratory precision (σR) was within the 0,7–2,9% range. 3) Expanded uncertainty (U) for different soil fractions ranged from 0,9 to 3,9%. Conclusions. The calculated metrological characteristics of determining the granulometric (grain) composition of soils using the pipette method facilitates the internal control of the measurements quality, promoting the quality and confidence in the laboratory work.

Assessment of soil properties in technogenically disturbed lands of Kemerovo Oblast – Kuzbass

Recultivation is a critical operation after mining operations. In Kemerovo Oblast – Kuzbass, Russia, a lot of land has suffered degradation due to stripping operations. The purpose of the study is to examine the technical, technological, and biological properties of lands technogenically disturbed as part of coal mining operations in Kuzbass. The object under study is soil and soil cover in the Talda coal mine at the experimental site and adjacent territories. The research goal is achieved through the following methods. The granulometric composition of soil is assessed using the areometric method. The structural-aggregate analysis is performed based on the distribution of aggregate content by size with a set of soil sieves. Water stability is established using the method of disintegration of soil aggregates under a layer of water up to 2 cm high for 10 minutes. The ecological condition of the soil is assessed based on its enzyme and biological activity. The conducted investigation reveals increased stoniness, hygroscopicity, and low humus content of soils on technogenically disturbed land plots. Technogenically disturbed lands are marked by more acidic and heavy metal-contaminated soils. No exceedances are detected for pesticides and radionuclides. The results demonstrate weak enzymatic (cellulolytic, catalase, dehydrogenase, urease, phosphatase, invertase, and soil respiration) and catalytic activity of the soils. All obtained results of assessment of soil conditions on the experimental site and adjacent territories should be used in planning further experimental work on conducting the biological recultivation phase to minimize random experimental errors associated with the influence of native vegetation cover and primary soil conditions on the survival of crops sown on the site.

Route assessment of state of the spawning stock in the lower ritral of the Utesny creek (Paramushir Island, northern Kuril Islands, Sakhalin Region)

The route survey in the lower part of the Utesny creek (Paramushir Island) was conducted to explore the state of spawning grounds for pink salmon Oncorhynchus gorbuscha and to examine their filling by spawners. The spawners were subjected to biological analysis with measuring their morphometric and physiological parameters. Besides, the data on granulometric composition of soils on the spawning grounds were updated.

Monitoring of Fertility and Ecotoxicological Condition of Reference Sites of Sod-Podzolic Soils of the Ivanovo Region

The results of agrochemical and ecotoxicological studies of the arable layer of reference plots of sod-podzolic soils for agricultural purposes of the Ivanovo region are presented, which were carried out in order to establish the level of fertility according to the main agrochemical indicators, the content of sulfur and trace elements, ecotoxicological state – by gross and mobile forms of heavy metals and arsenic. The deterioration of such indicators of soil fertility as the availability of ammonium and nitrate nitrogen, mobile potassium, the amount of absorbed bases and the capacity of cation exchange has been established. An increase in the content of mobile phosphorus, exchangeable calcium, magnesium and other absorbed bases was noted with an unchanged content of organic matter. The fertility of the studied soils was assessed by calculating the soil-ecological index. The provision of soils with trace elements and mobile sulfur has been established. The content of gross and mobile forms of metals in soils, with the exception of arsenic in the soils of individual sites, did not exceed the maximum permissible concentrations and clarks. The studied soils are slightly polluted and are not dangerous for cultivated plants and human health. According to the Pearson and Spearman correlation coefficients, the characters of the mutual influence of metabolic acidity, the content of organic matter and the granulometric composition of soils with the content of available forms of trace elements, gross and mobile forms of metals and arsenic are established.

Биологическая доступность 137Cs и 90Sr в дерново-подзолистых почвах в отдаленный период аварии на Чернобыльской АЭС

The content of 137Cs and 90Sr forms in soddy-podzolic automorphic and gleyic soils of different textures (loamy, sandy loamy, sandy) was studied. It has been established that over a long post-accident period, the physical and chemical forms of 137Cs and 90Sr have been transformed in soils, and a dynamic balance has come in their content. 137Cs compounds have undergone non-exchange fixation, and their content in the form available to plants is currently an insignificant fraction -5-15 %. 90Sr compounds, on the contrary, are predominantly in easily accessible forms, which make up from 60 to 75 % in soddy-podzolic soils, 67 % on average. The transfer factor of 137Cs, depending on the granulometric composition of soils, decreased on average in grain crops by 3.0-6.7 times, in potato tubers - by 5.0-7.5 times. The parameters of 90Sr intake into plants decreased most intensively in the first 1-2 years after the accidental fallout, which was mainly due to the transformation of its water-soluble compounds into exchangeable forms, and over the past 30-36 years they have not practically decreased. Due to the high mobility of 90Sr in the soil, the transfer factor into agricultural crops are significantly higher compared to 137Cs - into grain crops by more than an order of magnitude, into potatoes - by an average of 5 times. Currently, the bioavailability parameters of 137Cs and 90Sr have stabilized and no significant changes are observed. Therefore, based on the current situation and the transfer coefficients of these radionuclides from soil to plants, it can be concluded that the main problems associated with obtaining standard clean crop products can occur on soils contaminated with 90Sr.

Lichens in the Polar Deserts of the Northern Tip of the Novaya Zemlya Archipelago.

For the polar deserts of the Novaya Zemlya archipelago, the analysis of the dependence of the distribution of lichens on altitude above sea level, exposure by cardinal direction, the granulometric composition of soils, morphometric parameters of structural soils, the cover values of bryophytes and the total cover of cushion forms of plants and lichens was carried out. Based on 157 sample plots, nine lichenocenotypes (lichen community formed in a specific type of habitat) were identified. It is shown that with increasing height (during the transition from zonal to orozonal positions), the cover and the number of lichen species decrease. The cover of lichens also decreases with an increase in the cover of mosses. With an increase in the content of a fraction in soils of more than 0.125 mm, the species diversity and the cover of lichens increases. A total of 84lichen species were identified, of which Thamnolia vermicularis s. l. is classified as the most active, nine are highly active, 11-medium-active, the rest are little active and inactive. The current pattern of lichen distribution in the landscape of the far North of Novaya Zemlya is largely due to historical reasons-the youth of the landscape, recently freed from the ice cover, an exceptionally high degree of mobility of the cover of loose Quaternary deposits.

Creation of a GIS project of the results of testing technologies
 to reduce the accumulation of radionuclides in agricultural products

The article presents the results of the use of drones and GIS technologies during pilot testing of new types of agro-ameliorants and humic preparations to assess the effectiveness of reducing the accumulation of radionuclides in agricultural products grown on radioactively contaminated agricultural land in the Bryansk region. In the course of the work, an assessment of experimental farms was carried out to select the optimal sites for testing, as well as their digitization using an unmanned aerial vehicle equipped with a two-piece geodetic receiver to determine the exact geographical coordinates. Subsequently, with the help of a drone, fertilizer application was monitored, and the germination of agricultural plants was assessed after the application of agromeliorants.
 Based on the received materials, a library of electronic maps of the territories where the work was carried out was created in the ArcGis software environment. They included 4 farms of the Novozybkov district and 2 farms of the Krasnogorsk district. The library of electronic maps included cartographic information on the types of land use, surface contamination of soils with 137Cs, types and granulometric composition of soils, their agrochemical parameters, germination, yield, reduction ratio of 137Cs inflow into crop and forage production, as well as on the boundaries of elementary experimental plots with the designation type of fertilizer applied.

Основные диагностические показатели техногенно-нарушенных серо-бурых почв северо-западной части Апшеронского полуострова (Сумгаитский массив)

This article presents the results of research on the main diagnostic indicators of technosols transformed from grey-brown soils base in the northwestern part of the Absheron peninsula (Sumgait massif). The changes are shown in the soil profile of humus indicators, total nitrogen, CaCO3, pH environment, as well as granulometric composition of soils in every key area.

Ecological determinants of algal communities of different types of ecosystems

The results of studies of the environmental regularities of the formation of algal communities in soils of various ecosystems in the south of Ukraine are presented. 26 forest, 11 steppe and 3 saline ecosystems were investigated. The research has established the species richness of algae in each ecosystem and produced a multidimensional ordination of algal communities based on the analysis of the main components to clarify the factors that determine the composition of algal communities. The research has established the species richness of algae in each ecosystem and produced a multidimensional ordination of algal communities based on the analysis of the main components to clarify the factors that determine the composition of algal communities. Predictors determined by edaphic conditions and phytocenotic interactions associated primarily with edificators of ecosystems were used for the analysis. The ecological space of the studied ecosystems was formed by four main factors with eigenvalues greater than one, which explained 81.4% of the total variance. PC1 (34.82% of variance) is associated with the type of ecosystem and such edaphic parameters as pH, the availability of moisture in the habitat, and soil mineralization. PC2 (21.98%) reflects changes in the gradients of trophicity (humus content) and granulometric composition of soils. PC3 and PC4 additionally explain 16.04% and 9.27% of the total data variance, respectively. Their values mainly depend on the mineralization, trophicity, and moisture supply of edaphotopes, which, at the level of the composition of algae, is obviously associated with the heterogeneity of the ecological preferences of the algal species themselves, as well as the variability of ecological niches of ecosystems, due to which there are species more typical for other types of ecosystems in the communities. The use of the factor rotation procedure by the Varimax normalized method made it possible to concretize the taxa most associated with the main components: PC1 indicates the various Cyanobacteria species, PC2 – Chlorophyta, Streptophyta and Eustigmatophyceae, PC3 – Xanthophyceae and Euglenozoa, PC4 – Bacillariophyceae.

Environmental and Production Aspects of Using Fertilizers Based on Waste Elemental Sulfur and Organic Materials.

Crop fertilization with sulfur is an important part of agricultural practices, as is the systematic increase in soil organic matter content. Materials of waste origin constitute a source of plant-available sulfur, as well as soil organic matter. The study was to verify the hypothesis assuming that combining waste sulfur pulp and its mixtures with organic materials enables simultaneous soil enrichment with readily available sulfur and organic matter. A 240-day incubation experiment was conducted, on two soils: very light and heavy; with two sulfur doses applied to each soil (20 and 40 mg S/kg d.m. for very light soil, and 30 and 60 mg S/kg d.m. for heavy soil). The sulfate sulfur content in the incubated soil material, treated with the addition of sulfur pulp and its mixtures with organic materials, increased significantly up to day 60 and then decreased. The application of these materials significantly increased the content of available sulfur and decreased the pH value of the incubated material. The effect of the introduced materials on dehydrogenase activity depended on soil granulometric composition (the impact of the applied materials on the activity of these enzymes in very light soil was small, and in heavy soil, their activity was usually limited by the presence of introduced materials). Application of the studied materials had little effect on the total organic carbon content in the incubated soil material (a significant change in the value of this parameter, in relation to the control soil, was recorded in some treatments of heavy soil).

Study of the dynamics of grass yield within the agricultural landscape based on long-term monitoring

Yield monitoring of a five-component grass stand in a breeding field within a moraine hill was carried out in 2003- 2018 in order to find patterns of its dynamics in the agrolandscape. The grass was used in the conditions of the Tver region without fertilizers in a single-cut mode in a field crossing all microlandscape positions of the hill (transcct) and divided into 30 plots. Annual data on productivity of grass mixture on each plot are presented in the form of: 1) absolute yield (specific hay yield); 2) relative yield (expressed as a percentage to maximum yield on a transect in a definite year). It was revealed that the yield of grasses is maximum in the central parts (≈ 6.5 t/ha) and minimal in the upper parts of the hillsides and at the top (≈ 5.2 t/ha). Time variability of yield depends on the geological structure of the soils ‒ increases with the transition from powerful binomials (≈ 40 %) to low-powerful ones (≈ 65 %). Correlation analysis showed that the transition to relative units (% of the yield) can significantly reduce the impact of climate on data variability. The maximum coincidence of temporal dynamics of different yield indicators is noted at the upper elevations ‒ here climatic conditions do not have a significant impact on the yield, as on slopes. Changes in the sum of the active temperatures have the greatest influence on the yield. Average indicators of correlation coefficients of yield and temperature sums are negative on the plots of soil distribution on powerful and medium-powerful binomials and positive on soils of low-powerful binomials. There has been found an inversely proportional dependence of the absolute yield of grasses on the sums of active temperatures in the pre-cut periods and in September and directly proportional in the second half of summer. Increasing the sum of temperatures contributes to a decrease in relative yields on sandy soils and optimizes the production process on loams and light loams. Dispersion analysis has shown that the main influence of temperatures on absolute yield is exerted by soil hydromorphism. The degree of impact of temperatures on relative yield depends on the nature of water exchange in the agrolandscape, the exposure of slopes (energy) and granulometric composition of soils. The results will make it possible to adapt measures for the placement of grass stands, regulation of water and thermal regimes of soils to farm conditions.

Кинетика загрязнения почв тяжелыми металлами

The paper shows that the rate of soil contamination with heavy metals depends on a combination of soil properties: humus content, cation absorption capacity, granulometric composition of soils. The rate of absorption of heavy metals in soils depended on the position of the soils in the catena. On ordinary chernozems for plateaus and slopes, the content of mobile forms of lead was estimated by the equation: Pb = 20.1 - 0.02 N cm, where H is the depth of the layer r = -0.72, for the accumulative relief of the beam Rb = 27.4 - 0.14 N cm, r = -0.86. The rate of accumulation of heavy metals in soils differs for gross and mobile forms of compounds, for short-term and long-term forecasts. Thus, the change in the content of mobile forms of lead in chernozems was estimated by the equation: Y = 0.143t + 1.42; R2 = 0.6; for cadmium, Y = 0.003t + 0.0003; R2 = 0.9. For the short-term forecast, Rb = 0.143t + 1.42, R2 = 0.63; for the medium-term forecast, Rb = 0.417t + 1.7; R2 = 0.71. It is proved that when making forecasts of soil pollution with heavy metals, it is necessary to take into account the combination of soil properties, the position of the relief, the forecast period - the growing season, a number of years. Keywords: HEAVY METALS, SOIL POLLUTION, KINETICS OF PROCESSES, FORECAST

КАЧЕСТВО ВОСПРОИЗВЕДЕНИЯ СОСТОЯНИЯ ПОЧВЫ МОДЕЛЬЮ ДЕЯТЕЛЬНОГО СЛОЯ СУШИ ИВМ РАН - МГУ В СОСТАВЕ МОДЕЛИ ПРОГНОЗА ПОГОДЫ ПЛАВ

In situ soil moisture and temperature observations are used to evaluate soil moisture and temperature analysis of the global atmospheric model SL-AV for the summer season of 2014 across Western Europe. It is shown that the seasonal temperature analysis trends are reproduced better than the seasonal trends of soil moisture. Numerical experiments with the offline land surface scheme demonstrated that the implementation of the Mualem-van Genuchten water retention curve has the advantage for describing the processes of soil moisture transfer in comparison with Brooks-Corey parameterization. The last one is used in the basic version of the model. The Mualem-van Genuchten function provides better computational stability of the soil model in case of soils with high coarse grain content. An important contribution to the soil moisture error in the analysis and forecast is caused by specifying an inaccurate profile of the soil granulometric composition. It indicates a need to involve state-of-the-art databases for soil characteristics

Polyarenes Distribution in the Soil-Plant System of Reindeer Pastures in the Polar Urals

Humic substances of soils consist of various organic compounds, including polycyclic aromatic hydrocarbons (PAHs). Soil as a fairly stable medium allows the correct use of polyarenes as markers of the humus formation process. Monitoring of the accumulation of PAHs as resistant organic toxicants is also necessary due to their carcinogenic and mutagenic properties. Natural plant resources serve as the feed base of northern reindeer husbandry. In this study, high-performance liquid chromatography in a gradient mode and gas chromatography-mass spectrometry methods were used to estimate the content of PAHs in mountain tundra and meadows of the Polar Urals (Russia). The accumulation of polyarenes in soils on carbonate rocks of the Bolshoi Paipudynsky ridge occurs mainly in the process of soil formation and largely depends on factors such as productivity of plant communities, the composition of standing biomass, the site’s position in relief, the granulometric composition of soils, cryogenesis process and pyrogenesis. According to the set of polyarenes, their number, and ratio, the studied objects were classified into separate groups by discriminant analysis. The most typical representatives of pedogenic origin are naphthalene and phenanthrene. The accumulation features of dibenz[a,h]anthracene and benz[b]-, benz[k]fluoranthene, benz[ghi]perylene, and benz[a]perylene are shown. In mountain tundra landscapes, the characteristics of PAHs can be used to diagnose the intensity and direction of soil formation processes in general and humification in particular.

Современное использование земель бассейна реки Оса (Верхнее Приангарье)

The territory of the Osa river basin was studied, where under the steppe and forest-steppe vegetation types of soils are common that are not typical for the taiga zone: real chernozems with a relatively thick humus layer, sometimes reaching 45-50 cm, dark humus soils and other types of fertile soils. It has been established that hydrometamorphosed chernozems with a thickness of the humus horizon of more than 1 m are widespread in low relief areas, under conditions of increased moisture. a series of expeditions was carried out to study the soils of natural, arable and fallow lands, as well as pastures. The content of humus and the granulometric composition of soils were determined (types of natural soils: gray typical, hydrometamorphosed chernozem, thin chernozem, typical dark humus; types of agrogenic analogues of natural soils: typical agroabrazem, dark agrozem, typical agrogrey, agroserohumus typical, agrodark humus typical, hydrometamorphosed agrochernozem, typical agrochernozem; more than 30 samples). The influence of these indicators on soil fertility is considered. The change in the nature of land use in the period from 1983 to 2013 has been studied, and possible reasons for these changes. A map of modern land use in 2021 was made. A comparison was made of the nature of modern land use with their use in 1983, 1997, 2005, 2013.

Современное использование земель бассейна реки Оса (Верхнее Приангарье)

The territory of the Osa river basin was studied, where under the steppe and forest-steppe vegetation types of soils are common that are not typical for the taiga zone: real chernozems with a relatively thick humus layer, sometimes reaching 45-50 cm, dark humus soils and other types of fertile soils. It has been established that hydrometamorphosed chernozems with a thickness of the humus horizon of more than 1 m are widespread in low relief areas, under conditions of increased moisture. a series of expeditions was carried out to study the soils of natural, arable and fallow lands, as well as pastures. The content of humus and the granulometric composition of soils were determined (types of natural soils: gray typical, hydrometamorphosed chernozem, thin chernozem, typical dark humus; types of agrogenic analogues of natural soils: typical agroabrazem, dark agrozem, typical agrogrey, agroserohumus typical, agrodark humus typical, hydrometamorphosed agrochernozem, typical agrochernozem; more than 30 samples). The influence of these indicators on soil fertility is considered. The change in the nature of land use in the period from 1983 to 2013 has been studied, and possible reasons for these changes. A map of modern land use in 2021 was made. A comparison was made of the nature of modern land use with their use in 1983, 1997, 2005, 2013.

Post-fire tree regeneration in forests of the Tikhvin Ridge, North-West Russia

We assessed the effect of ground fires on the success of advanced regeneration of tree species on gentle hilly ridges of terminal moraines of the North-Eastern part of the Leningrad Region. To study the juvenile generation of tree species, we carried out a reconnaissance survey of transects in the forest areas affected by wildfires. The forest stands were 10–12 years old. The stem numbers and heights of the regenerating tree species were recorded. The correlation analysis was used to determine the degree of influence of external factors on forest regeneration, including soil conditions and the burnt area size. We found differences in the species composition of stands with a predominance of deciduous and coniferous species depending on soil and hydrological conditions. We also found a relationship between soil factors and spruce and pine regeneration size in stands with a predominance of coniferous and deciduous species. The soil granulometric composition influenced proportions of coniferous and deciduous trees in post-fire stands. Using the knowledge obtained about the stand composition, we can forecast the future development of forest stands and prescribe the optimal forest management regimes.