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The agricultural soils of the Happy Valley-Goose Bay (HV-GB) region of Newfoundland and Labrador, Canada are Podzols that are converted from boreal forest and have limited productivity due to their sandy texture, acidity, low soil organic matter (SOM), cation-exchange capacity (CEC), and water and nutrient retention capacity. Although numerous studies advocate biochar for mitigating soil quality problems and enhancing agronomic productivity, there is limited information on managing biochar for boosting the productivity of Podzols under newly converted agricultural lands. A 5 year experiment evaluated the impact of eight biochar rates (0–80 Mg C·ha−1) on soil properties including SOM, CEC, and availability of plant nutrients and metals in agricultural soils of HV-GB. Both immediate and long-term impacts were thus assessed. Biochar generally improved soil fertility indicators. Although the largest rates (40 and 80 Mg C·ha−1) led to the greatest changes, significant changes were also found with rates as low as 10 Mg C·ha−1. Increasing biochar rates had diminishing returns for quality parameters of soil. The impact of biochar decreased with time after application, but the largest rate led to longer lasting effects. Although biochar was incorporated in topsoil, its effects were also measurable in the subsoil, albeit with a temporal delay, usually of 1 year. Thus, given the diminishing returns of increasing biochar rates, and that beneficial effects diminish over years, it is advisable that biochar be added in smaller amounts immediately after conversion, as little as 10 Mg C·ha−1, with regular supplementation as needed.

Chronosequence studies of soil formation and ecosystem development provide important insights into the pathways and rates of change occurring on centennial and millennial time scales. In cool or temperate humid environments, Podzols are the predominant soil type formed under coniferous forests in coarse-textured parent material and have been a major focus of chronosequence studies. This study examined the rate and mechanisms of Podzol development and related forest productivity in a sand dune chronosequence in a hypermaritime climate in coastal British Columbia (BC). The sequence spans 10 760 ± 864 yr over eight sites and is the first documented chronosequence in coastal BC to span most of the Holocene Epoch. Soil samples from each genetic horizon were analyzed for bulk density, pH and concentrations of total carbon (C), pyrophosphate- and oxalate-extractable aluminum (Al) and iron (Fe), and total elements. Within ∼3500 yr, a mature Podzol had formed, with cemented horizons (ortstein and placic) present. Organo-metallic complexation appeared to be the dominant mechanism involved in podzolization. Despite a mild, moist climate conducive to chemical weathering, all soils had similarly low values for the chemical index of alteration, suggesting that congruent dissolution of primary minerals may be occurring. Ecosystem retrogression is apparent in the latter stages of the chronosequence — a phenomenon not previously documented in coastal BC. Further research is needed to examine the interactions of nutrient limitation, soil physical barriers, and other possible drivers of ecosystem retrogression.

The dark-humus soil type was included in the updated legend of the Soil Map of the Russian Federation at scale 1 : 2.5 M, converted to the system of Soil Classification of Russia. The soil profile starts with the dark-humus horizon gradually merging to the parent rock; any mid-profile diagnostic horizons are absent. Large areas of dark-humus soils are found in the forest-steppe, steppe and taiga zones of the European Russia, Western and Central Siberia, in the Trans-Baikal region, the Altai-Sayany Mountains, and the Caucasus. The type of dark-humus soils comprises both mesomorphic soils (of normal moisture conditions) and soils with additional surface or ground-water moisture. The main prerequisites for the formation of dark-humus soils are, on the one hand, the climatic conditions favorable for the dark-humus horizon formation, and, on the other hand, parent material - mostly derivates of hard rocks, restricting the development of mid-profile diagnostic horizons. In the updated map, the following initial legend units are partially or completely converted to dark-humus soils: several units of chernozems, dark-gray forest and gray forest non-podzolized soils, soddy-taiga base-saturated and slightly unsaturated soils, several mountain soils, a significant part of soddy-calcareous soils, as well as some mountainous forest-meadow soils. The diversity of dark-humus soils subtypes is determined by secondary carbonate features, weak signs of clay accumulation and podzolization, alteration of the mineral mass, gley and cryogenic phenomena.

Very different soil types occur across a few tens of meters on dolostone, in a never glaciated karst landscape in the Lombard Pre-Alps (Selvino, Italy). This substrate is locally enriched in well-crystallized sand-grained quartz. The quartz content is responsible for the localized genesis of Podzols. Other soil types observed in the area include strongly rubified (Terra Rossa) horizons (paleosols), preserved in the most protected dolostone cracks. Non-rubified Luvisols and Cambisols were observed in karst dry valleys and dolines while Rendzic Leptosols/ Phaeozems were common on the steepest slopes. Such a variety of soils was explained assuming different parent materials (dolostone, silica-rich dolostone, with different amounts of aeolian inputs, ascertained using textural properties, mineralogy, micromorphology, total element composition, mass balance calculations, rare earth elements, and stable elements. Many soils were highly polycyclic, with different layers associated to different parent materials and characterized by different pedogenic processes evidencing different ages. We were thus able to distinguish the horizons mainly developed from the dissolution of the dolostone from those formed in Pleistocene loess. The geochemistry of all surface soil horizons, including Podzols and Rendzic Leptosols/ Phaeozems, apparently formed from pure or quartz-rich dolostone dissolution, has been influenced by recent aeolian additions (likely Saharan dust), with deeply modified effects according to different pedogenetic processes acting locally. Saharan dust, in fact, significantly increased metal and rare earth elements contents compared to the substrate, also in the youngest and least weathered soil types.

Indicators of the permissible content of oil and products of its transformation for podzols of illuvial-ferruginous, sod-podzolic, peat boggy raised soils of the Perm territory are presented. The sampling of the selected soil types was carried out, with which experiments on phytotesting, biotesting of the quality of water extracts with differentiated oil pollution were carried out. The assessment of chronic phytotoxicity was carried out according to the reaction of three species of terrestrial plants: spring wheat, pea sowing, and hybrid spruce. The water extract of contaminated soils was tested on chlorella and daphnia. As a result, quantitative indicators of the permissible concentration of hydrocarbons in soils after reclamation for agricultural and forestry lands were obtained.

Manganese (Mn) has been identified as a regulatory bottleneck in carbon (C) turnover because of its role as an enzymatic co-factor in the oxidative decomposition of C by Mn-peroxidase (MnP). We tested this limit on decay using forest soils from coastal British Columbia with contrasting Mn concentrations. Moderately weathered soils (Brunisols) had an average 3.6-fold increase in MnP activity within the upper soil profile in comparison to highly weathered Podzols. Ordination of the Agaricomycete fungal community, which are responsible for MnP production, confirmed significant differences in assemblages between soil types for saprotrophic fungi, particularly species within Agaricales, Trechisporales and Auriculariales. Ectomycorrhizal fungi of Pseudotsuga menziesii were equally aligned with soil type and select taxa more abundant on Brunisols may have supplemented MnP activity. A laboratory incubation with an Mn amendment produced significant interactions in MnP activity by soil type. Surprisingly, MnP activity of both Brunisol substrates declined substantially with an amendment (-56% and − 40% for forest floor and mineral soil, respectively), in contrast to Podzols (-30% and + 26%, respectively). This inhibitory response was linked to considerable uptake of the added Mn in Brunisols, and underscores how Mn2+ likely operates directly on fungi as a regulator of mnp transcription for MnP production. Our study highlights a new perspective concerning the abiotic drivers underpinning the expansive soil C stocks across perhumid temperate rainforests of the Pacific Northwest.

Short-term freezing of the soil surface can occur practically throughout the entire territory of Russia. This phenomenon stimulates CO2 emission from the soil. In this regard, in laboratory conditions, we studied the dynamics of CO2 emission from soils of various natural zones with periodically repeating short-term freeze–thaw cycles. For the study, samples were taken from the upper horizons of the following soils: Reductaquic Turbic Cryosol (Loamic), Reductaquic Turbic Cryosol (Loamic), Spodic Turbic Cryosol (Arenic), Histic Cryosol (Glacic), Albic Rustic Podzols (Arenic), Haplic Luvisol (Loamic, Aric), Haplic Chernozem (Loamic, Pachic), Rendzic Leptosol (Humic), Haplic Chernozem (Siltic), Gypsic Solonetz (Loamic, Columnic), Gypsic Vertisol (Hypereutric), Haplic Kastanozem (Siltic), and Haplic Calcisol (Loamic). It was found that the dynamics of CO2 emission during the freeze–thaw cycles were similar for all soils. The CO2 emission from frozen soil samples was reliably determined. Subsequent soil thawing promoted a pulse increase in the CO2 emission in comparison with that before and after the freeze–thaw cycle regardless of the soil type. Thus, for the first time, it has been shown on a wide range of soils that a significant response of СО2 emission to freeze–thaw of the soil surface can occur in any natural zone. The magnitude of the response depends on the soil properties, primarily on the organic matter content. The influence of single freeze–thaw cycles on the annual CO2 flux is insignificant. However, frequent freeze–thaw cycles can affect the CO2 flux both within individual seasons and throughout the year.

We have revealed the dependence of current soil-forming processes in laylands on the period of theirs overgrowing, landform, and cultivation intensity. The main object of research is represented by regraded agrosoddy-podzolic soils (Albic Glossic Retisols (Loamic, Aric, Cutanic, Ochric)), differing in the overgrowing period, cultivation rate, and texture, and located on transit and accumulative elements of the landscape. The soils have been studied during soil-ecological surveys in the Udmurt Republic and in a long-term field experiment. It has been revealed that all major changes in layland soils occur in the former plowed layer, which is subdivided into two sublayers. Humus formation is intensive in the upper 10-cm-thick part of the plow layer, which results in higher humus content, total exchangeable bases, and structure coefficient. The zonal podzolization process is activated in the lower part of the plow layer (from 10- to 20-cm-thick) and results in lower content of humus and exchangeable basis, and in higher acidity. After the 40-year-long period of overgrowing, the properties of these sublayers become similar to those of the AY (gray-humus) and EL (eluvial) horizons of virgin soils, respectively. The changes of all the parameters during layland overgrowing are stepwise. Differentiation of the formed plow layer is the most intensive in soils on transit elements of the catena. More favorable moisture conditions of the accumulative positions in catena result in higher productivity of biocenoses and more intensive humus formation. Differentiation of the former plow layer is more intensive in soils of the increased and high cultivation rate.

The background content of total petroleum hydrocarbons (TPH) in the most common soils of the Lower Amur region and Northern Sakhalin was determined. About 300 samples taken from the surface layers and horizons of 8 typical soil pedons were analyzed. The accumulative nature of TPH distribution in the soil profile was established, and their highest content was revealed in the organogenic horizons. The soils of eluvial landscapes (Podzols, Spodic Cambisols, Fulvic Cambisols) contain a smaller amount of TPH compared to the soils of accumulative landscapes (Histosols, Fluvisols). The maximum content of TPH was found in the Spodic Hyperalbic Technosols. The content of TPH in the anthropogenic abrasives of the Lower Amur region is estimated as acceptable, the level of pollution in the anthropogenic abrasives in Northern Sakhalin varies from low to very high. The results obtained on the background content of TPH can used for assessing of soils pollution and in conducting ecological monitoring studies.

The prokaryotic and fungal biomass was estimated by luminescent microscopy; the number of ribosomal gene copies of microorganisms was determined by the real-time PCR method, and the taxonomic diversity of culturable micromycetes in Albic Podzols was studied along the pollution gradient (1.5, 8, 15, and 50 km) from the Kandalaksha aluminum smelter, Kola Peninsula. In the soils of all sites, the largest number of ribosomal gene copies was found for bacteria (4.2 × 1010…10.3 × 1010 gene copies/g soil). For fungi and archaea, this number varied between 0.4 × 1010…3.1 × 1010 gene copies/g soil. There was a significant increase in the actinomycete biomass near the smelter, while the biomass of bacteria and fungi did not change at different distances from the source of emissions. Mycelium and spores of fungi were represented mostly by small forms with a diameter of 2–3 µm. In a heavily polluted area (8 km from the smelter), the proportion of spores was more than a half of the total fungal biomass, and the number of large spores was maximum (33.6%). The length of the fungal mycelium varied from 92.27 to 206.26 m/g, while there were no regularities in its distribution along the pollution gradient. There was a decrease in the diversity of soil micromycetes at the level of genera and higher taxa along the pollution gradient. The change in community structure from polydominant (background area) to monodominant (near the smelter) was found. Penicillium spinulosum dominated in all contaminated sites within the 15-km zone. In the background area, in addition to the above species, Trichoderma koningii, P. implicatum, and a group of fungi with sterile mycelium were among the dominants.

Aims The morphological traits of fine roots change with forest succession and soil weathering. However, low tree species diversity in boreal forests may limit plastic responses of the roots to soil nutrient loss. We tested whether pine trees (Pinus sylvestris L.) have root plasticity to change fine root allocation to deeper soil horizons in response to varying degree of podzolization. Methods We compared root biomass in two sand dune chronosequences (aluminium (Al)/iron (Fe) oxide-poor coarse-textured sand vs. oxide-rich fine-textured sand) in Estonia. Results We found that faster podzolization in coarse-textured soil promotes migration of Al/Fe oxides and phosphorus (P) into deeper horizons and reshapes the depth distribution of fine root biomass. A decrease in P availability in the coarse-textured soil profile increases fine root biomass and length in both the organic and mineral horizons. In the fine-textured old soil, fine root distribution increases in the mineral soil (especially, spodic horizon) rich in oxide-bonded P.Conclusion Pine roots have two plasticities in low-diversity boreal forests – changing root morphological traits and changing depth distribution of root biomass, depending on the abundance of Al and Fe oxides and the depth distribution and dominant form of P.

The soil diversity of the Central ecological zone of the Lake Baikal drainage basin within the Buryat Republic has been analyzed. The soil cover is formed by 38 soil types. The compiled updated soil map of the region includes 18 soil contours of the dominating, accompanying, and occurring soil types. The area assessment of soil resources has been performed. The revealed predominating effect of the vertical zonality on the soil spatial distribution is the most pronounced in high and mid-altitude mountains. The soil cover of high mountains is dominated by poorly formed soils (lithozems and petrozems (Regosol and Leptosol)) with accompanying soils, as well as gleyzems (Gleysols) with peat-gleyzems (Histic Gleysols) and peat-lithozems (Histic Regosol). More than half of the region is occupied by soils of the mid-altitude mountains with the complicated soil cover dominated by podburs (Ferric Umbric Podzols) and burozems, as well as by podzols, soddy-podzols (Folic Podzols), soddy-podburs (Ferric Folic Umbric Podzols), etc. Low mountains are mainly occupied by podzols and gley soddy-podzols (Folic Gleyic Podzols) with accompanying soddy-podzols (Folic Podzols) and soddy-podzolic-gley soils (Folic Gleyic Retisols). Soils of mountain depressions are mainly represented by gray metamorphic soils (metamorphic Folic Umbrisols), soddy-podburs (Ferric Folic Umbric Podzols) in combination with soddy-gray soils (Folic Umbrisols), as well as by humus psammozems (Mollic Arenosol). In floodplains, estuaries, and river deltas, various complexes of alluvial soils, that is, dark humus (Umbric Fluvisols), gley dark humus (Umbric Gleyic Fluvisols), stratified alluvial (Fluvisols), soddy-gley (Folic Gleyic Fluvisols), peat-gley (Histic Gleyic Fluvisols), etc., are formed. Peat eutrophic soils (Histosols) and peat-gleyzems (Histic Gleysols), as well as peat-gley soils (Folic Gleysols) and peat-cryozems (Histic Cryosols), occur on swamp massifs. Lakesides are mainly occupied by dark-humus gley (Gleyic Phaeozems) and peat eutrophic soils (Histosols). Saline soils are practically absent in the region.

The succession of natural vegetation on the former arable soils triggers the processes of postagrogenic restoration of soil ecological functions specific of a particular bioclimatic zone. We analyze the postagrogenic dynamics of a set of soil characteristics in the upper (0–5 and 5–10 cm) layers of former arable horizon by the case study of the chronosequence of Retic Albic Podzols (agrosoddy podzols, southern taiga, Kostroma oblast, Russia) withdrawn from agricultural use 15, 20, and 45 years ago. The following soil characteristics are determined: pHKCl; the contents of soil organic carbon (SOC), total nitrogen (TN), and dissolved carbon and nitrogen (DOC and DON); basal respiration (BR) rate; carbon of microbial biomass (Cmic); and relative indicators of the state of microbial community. In addition, absolute (HIX1) and relative (HIX2) humification indices of dissolved organic matter (DOM) are assessed for the soil layer of 0–5 cm in the studied soil chronosequence, as well as the stratification ratio (SR (0–5 : 5–10)). The following changes are observed in the upper layers of the former arable horizon over 45 years of postagrogenic succession: (1) a statistically significant decrease in the pHKCl and humification index of DOM; (2) an increase in the SOC, TN, and Cmic contents and BR rate; and (3) a considerable stratification according to the SOC and TN contents and microbial properties. The highest values of SR for the SOC and TN are observed in the soil of the old-aged forest; for the microbial properties, in the 45-yr-old abandoned soil. Thus, the main characteristics and ecological functions of Retic Albic Podzol gradually restore during the secondary succession on the former arable land in the southern taiga zone.

Aims: We investigated morphological variations in podzols caused by changes in soil porosity and permeability upon the growth of large tree-roots in a tropical barrier island (Ilha Comprida, Brazil). Methods: Soil morphology was described in a continuous lateral sequence of podzols on a 35 m-long cliff. A soil thin section was used to characterize organic matter (OM) accumulation and to estimate soil porosity, permeability, and saturated hydraulic conductivity (Ksat). Soil texture and the contents of organic carbon, Al, and Fe were determined for each pedogenic horizon containing large tree-roots. The evolution of podzol morphology was interpreted in the context of age determinations by optically stimulated luminescence and 14C. Results: Taproots of cashew trees (Anacardium occidentale) penetrated the cemented Bhm horizon and the massive-clayey 2Cgj horizon. Aligned with the taproot, we found a vertical OM-band with lower porosity, permeability, and Ksat than the adjacent Bh and E horizons. Irregular or broken boundaries between the E and Bh horizons were caused by large tree-roots. While the maximum age of these podzols is 3390 ± 530 years, significant and rapid changes in the Bh-horizon morphology occurred within the lifetime of the cashew trees (~ 50 years). Conclusions: The interplay between reduction in flow adjacent to large taproots and the enhanced vertical infiltration at depth has resulted into the development of irregular and broken boundaries between the E and Bh horizons. Because tree-roots alter both local soil porosity and water flow paths, they simultaneously cause the formation and degradation of podzol Bh-horizon.

Review of the monograph by A.D. Fokin and S.P. Torshin “Plants in the Life of Soils and Terrestrial Ecosystems. Nontraditional Approaches and Solutions on the Behavior of Biologically Significant Elements” published in 2020 by Lap Lambert Academic Publishing, ISBN 978-620-2-53005-7. In the monograph by A.D. Fokin and S.P. Torshin, the reader finds an original and not always traditional for soil scientists, consideration and discussion of a number of fundamental problems of the development of a soil profile and modern soil functioning and of the role of plants and microorganisms in these processes. The authors of the monograph make us think about the validity of some generally accepted concepts and hypothesis, especially those concerning transport flows of matter in soils and their modeling. Attention is drawn to the usually underestimated role of the uplifting – ascending fluxes of matter along the conductive systems of plants, and to the localization of living roots and organic residues in soils. The latter factor plays an important role in the development of intrahorizontal differentiation of the soil material and in the root nutrition of plants. The great advantage of the book is the availability of abundant experimental material obtained by unique methods developed by the authors, simple and effective, which have no analogues in the world literature. Application of these methods, allows, in particular, determining the lifetime of the aggregate in soddy-podzolic soils and establishing the trends in the root uptake of radionuclides from the surface and from the inner part of peds. In the end a general conclusion is formulated that in the course of modern soil functioning, the soil-profile redistribution of matter is performed mainly within the limits of the biological cycle of elements. Many of the problems and ideas discussed in the monograph go far beyond the soil science, therefore the book is of great interest for a wide range of specialists in environmental and plant sciences, in agricultural chemistry, forestry and in various branches of geosciences.

Geochemical features of permafrost-affected (Folic Protic Leptic Cryosols, Histic Protic Leptic Cryosols) and Al-Fe-humus soils (Folic Leptic Entic Podzols, Histic Leptic Entic Podzols) have been studied. These soils are widespread in taiga forests of Khentei, Eastern Sayan, and Khangai mountains. Data on the microelemental composition of parent rocks are given. The dispersion coefficients of most of the studied microelements in parent rocks relative to the lithosphere exceed 1.0, which indicates the predominance of processes of material removal. Differences in the concentrations of microelements in soils largely depend on the texture of parent rocks. Data on the morphology, physicochemical and chemical properties of soils and on the distribution of microelements in the soil profiles are discussed. The studied soils differ both in the absolute contents of microelements involved in the biological cycle and the intensity of their biogenic migration. The intensive biogenic migration of elements results in their accumulation in organic and raw-humus soil horizons and in the accumulative patterns of element distribution in the soils of the altitudinal zones of forest vegetation. In contrast to Cryosols, the organic and raw-humus horizons of Entic Podzols are characterized by a less intensive accumulation of microelements. In the Al–Fe-humus (spodic) horizon of Podzols, the concentrations of Pb, Cr, Mo, and B are above the clarke level. Spodic horizons of the studied soils act as chemosorption geochemical barrier for some biophilous elements and elements of the iron group.

The spatiotemporal variability of CO2 emission from soils of Kursk under different land uses, pollution levels, and soil geneses has been assessed. Data on the seasonal dynamics of CO2 emissions in background (forested recreational areas) and urban soils under the anthropogenic impact are presented. Seasonal dynamics of soil СО2 emission depends on a number of factors: season, type of soil, organic matter content, anthropogenic modifications of soil profiles, hydrothermic conditions, and heavy metal pollution. Soil hydrothermic conditions to a greater extent determine the intensity and characteristics of the seasonal dynamics of soil CO2 emission with a maximum in summer. In anthropogenic soils, multidirectional transformation of soil CO2 emissions is noted. The intensity of CO2 emission from soils of various geneses is quite different. Heavy metal pollution of the soil has an ambiguous effect on the CO2 emission processes. The CO2 emission rate from Urbic Technosol increased by 16.4% in comparison with that from the background Luvic Chernozem (Loamic, Pachic), while for Technic Greyzemic Phaeozem (Loamic) this parameter decreased by 47% in comparison with the background Greyzemic Phaeozem (Loamic). In Carbic Podzols polluted by heavy metals, the averaged CO2 emissions are generally similar to those from the background soils unpolluted by heavy metals.

This paper describes typical and humic petrozem soils developing in the most high-altitude (goltsy) zone of the Khibiny Mountains under three predominant types of primitive plant communities representing different stages of the primary succession. The profiles of such soils are not differentiated by the content of most elements, except for phosphorus concentrated in the surface organogenic horizons. By their chemical and physicochemical properties, soils of the cold mountain (goltsy) desert are similar to Entic Folic Podzols formed under dwarf-shrub vegetation in the mountain-tundra located downslope. The biological activity of petrozem soils is lower than or comparable to that in soils of dwarf-shrub tundra. It is established that the microbial activity increases and soil organic matter stabilizes when the vegetation becomes more patterned. Overall, microbial communities of petrozem soils are well adapted to extreme environmental conditions.

The topic of vegetative cover rehabilitation of industrial barrens sites has a worldwide significance, especially given the potential of the polluted soils themselves to be “secondary pollution sources.” The goal of this study was to determine the effect of peat addition to the lime + vermiculite-lizardite combined amendment on plant growth in the soils from the vicinity of the Ni/Cu smelter in the Kola Peninsula, Russia. Given the complexity and time-consuming nature of field studies, we decided to test the selected amendments under laboratory conditions first. Surface horizons from two Spodosols (0-20 cm) were collected in the vicinity of the Ni/Cu smelter. Lolium perenne was cultivated in pots for 21 days under controlled conditions. The difference in plant growth with and without peat was not substantial. In other words, the addition of peat did not improve the efficacy of the lime + vermiculite-lizardite combined amendment in promoting plant growth. Therefore, the challenge of reducing ryegrass exposure to soil metals remained unsolved., El tema de la restauración de la cubierta vegetal en áreas industriales degradadas tiene una importancia mundial, debido a su potencial como fuente secundaria de contaminación. El objetivo de este estudio fue determinar el efecto de la adición de turba a la enmienda combinada de cal + vermiculita-lizardita sobre el crecimiento de las plantas en los alrededores de una fundición de níquel y cobre, en la Península de Kola, Rusia. Dada que los estudios de campo son complejos y precisan tiempo, se decidió probar primero las enmiendas en condiciones de laboratorio. Se muestrearon los horizontes superficiales de dos Spodosoles (0-20 cm) en las cercanías de dicha fundición. La especie Lolium perenne se cultivó en tiestos durante 21 días, en condiciones controladas. La diferencia en el crecimiento de las plantas entre los tratamientos con y sin turba no fue sustancial. En otras palabras, la adición de turba no mejoró la eficacia de la enmienda combinada de cal + vermiculita-lizardita para promover el crecimiento de las plantas en los suelos de las cercanías de la fundición. Por lo tanto, el desafío de reducir la exposición del L. perenne a metales en los suelos estudiados quedó sin resolver.

Background. Several theories have been proposed to explain the podzolization process. Currently, the role of organic matter in both weathering and immobilization in the illuvial horizon is clearly stated. The origin of soil organic matter and, accordingly, the various mechanisms of its influence on the soil material, create the basis of these theories. We assume that in the base-poor sandy soils under rich herbaceous vegetation with a well developed sod layer, the process of podzolization may also depend on CO 2 soil formation agent . Materials and Methods. Four localities along a Pinus sylvestris L . self-afforestation chronosequence with pine stands of 10, 20, 40 yrs and an adjacent semi-natural grassland area were investigated in order to determine the patterns of podzolization process on sandy glacial till deposits. Soil pH, exchangeable base, soil cation exchange capacity, total content of soil organic carbon, amorphous Fe, Si and Al and total contents of Al, Fe, Mn, Zn, Cd, Pb, Cu, Co, Ni, Na, K were determined. Statistical analysis of the results was performed using LibreOffice for Linux. Results. During the pine succession, a previously well differentiated into horizons podzolic soil under the grassland vegetation community gradually degrades. Previously well-defined albic and spodic diagnostic horizons disappear, the soil profile becomes more acidic, the soil organic carbon, the base cation content and the base cation saturation decrease, the leaching rate of aluminium and iron increases. Secondary podzolization features in the soil profiles were detected 40 years after the onset of afforestation. The podzolization has not been intensive enough to develop fully fledged albic and spodic diagnostic horizons over such a short period. Conclusions. Based on the obtained soil morphological, physical and chemical properties, three most important agents of podzolization are proposed as principal for the studied area. The main gent under pine forest is fulvic acids that are produced during coniferous litter decomposition. Low molecular weight organic acids and carbon dioxide produced to the rhizosphere by roots and a root associated microbiota are mainly involved in the podzolization process under the grassland ecosystem. Keywords : podzols, reforestration, carbon dioxide soil formation agent Received 15 May, 2021 ● Revision 28 May, 2021 ● Accepted 02 June, 2021 ● Published 30 June, 2021

It has been highlighted that forest productivity is related both to species richness and to soil fertility; however, thus far it has not been investigated which of these agents is more important for the productivity. The goal of this study was to examine this problem with regard to Scots pine (Pinus sylvestris L.) stands in Central Europe. The study was conducted in 129 plots located in SW Poland. The productivity of even-aged pine stands was estimated based on site index. Plant species richness was investigated regarding the total richness as well as the richness referring to particular forest strata (overstorey, understorey, herb layer). Soil fertility was studied regarding the nutrients’ stocks, the contents of fine-textural classes, pH, the TOC content and the values of Soil Trophic Index. The importance of the variables for the site index was examined using Spearman correlations and the stepwise regression. Productivity of the studied stands was predominantly correlated stronger to species richness than to soil properties being related to its fertility. The higher importance for the productivity of soil variables than of species richness was exclusively found for the poorest plots being represented by Podzols. This study highlights the high importance of species richness occurring in particular forest strata for the forest stand productivity, which could involve consequences for forest economy as well as for CO2 sequestration. Thus, the research delivers strong argument for the conversion of pine mono-stands occurring in Central Europe for mixed forests.

Elementary soil processes, as components of the soil-forming process, play an important role in the formation of morphological and genetic features of soils and are used for their genetic diagnosis. Eluvial-illuvial differentiation of the background profile for Precarpathian soils is due to the passage of processes from the group of eluvial, in particular podzolization, silting and gley-eluvial. The diagnostic criteria for these processes remain controversial and need further development. The article provides some justifications for their objectivity and reliability in identifying individual processes of soil formation and the results of establishing the genetic consequences of their passage. The formation of clay cutanes in the illuvion is considered to be an important sign of lessivage, but the presence of one and a half oxides may also indicate the passage of the processes of podzolization and in-soil clay forming According to another criterion - the presence of "optically oriented clays" in the illuvion is difficult to establish their migration path and the intensity of the lessivage process. Increasing the value of the ratio of silt content to the content of physical clay in the illuvial horizons compared to the eluvial horizons does not allow to distinguish the processes of podzolization and lessivage, and the same ratio in the illuvial horizon compared to the parent rock - lessivage and clay forming. Changes within the profile of the mineral part of the soil, which are reflected by the molecular ratios of SiO2:Al2O3 and eluvial-accumulative coefficients of aluminum, the values of silt and aluminum losses, also the profile distribution of montmorillonite are important criteria for the separation of loess and podzolization and indicate the decisive role of the latter in the formation of the profile differentiation of the soils of Precarpathians. Important criteria for gley-eluvial processes are higher losses from the upper podzolic illuminated of Fe2O3 layer than Al2O3, an increase in the molecular ratio of Al2O3:Fe2O3, the ratio of losses of Fe2O3 and Al2O3, also increase the criterion SiO2:Fe2O3/SiO2. Complementing the national system of parameters for the diagnosis and classification of soils with criteria that are characteristic of the substantive-genetic approach according to the WRB requires further study.

The total concentrations of metals (Fe, Mn, Cu, Ni, Cr, Sr) and their mobile forms extracted by an ammonium acetate buffer (pH = 4,8) were studied in soils samples collected from Nadym-Pur interfluve (West Siberia), near the northern limit of the taiga zone. The heavy metal content was determined in 55 background soil samples and in 25 pyrogenic ones. Gross content was determined on a spectrometer "SPECTROSCAN MAX-GV" using x-ray fluorescence analysis. Mobile forms of metals were determined on a ContrAA 700 atomic absorption spectrometer by flame and electrothermal methods. The statistics are calculated using the Excel software package. The study confirmed the weak accumulation of metals in the soils of the northern regions of Western Siberia. The total content below the soil world average for Fe is 5 times, Mn - 3 times, Sr - 2 times, Cr - 1,4 times. The content of mobile forms varies widely depending on the amount of organic matter. The percentage of mobile forms of metals from the total content was: Cr - 0.84%, Fe - 1,2%, Sr - 3,8%, Mn - 8,7%, Ni - 15%. In the profile of podzols, the distribution of mobile forms of metals has an eluvial-illuvial character. Mn and Sr accumulate intensively in the surface organogenic horizons, and the Fe content increases in the BF horizon. Minimum values are marked in horizon E. In pyrogenic soils, there is an increase in the content of mobile forms of metals due to the intake of ash. Metal content usually not exceeded the maximal permissible concentrations for soils.

Global significance of iron (Fe) and aluminum (Al) for the storage of organic matter (OM) in soils and surface sediments is increasingly recognized. Yet specific metal phases involved or the mechanism behind metal–OM correlations frequently shown across soils remain unclear. We identified the allocation of major metal phases and OM to density fractions using 23 soil samples from five climate zones and five soil orders (Andisols, Spodosols, Inceptisols, Mollisols, Ultisols) from Asia and North America, including several subsurface horizons and both natural and managed soils. Each soil was separated into four to seven density fractions using sodium polytungstate with mechanical shaking, followed by the sequential extraction of each fraction with pyrophosphate (PP), acid oxalate (OX), and finally dithionite–citrate (DC) to estimate pedogenic metal phases of different solubility and crystallinity. The concentrations of Fe and Al (per fraction) extracted by each of the three reagents were generally higher in meso-density fractions (1.8–2.4 g cm−3) than in the lower- or higher-density fractions, showing a unique unimodal pattern along the particle density gradient for each soil. Across the studied soils, the maximum metal concentrations were always at the meso-density range within which PP-extractable metals peaked at 0.3–0.4 g cm−3 lower-density range relative to OX- and DC-extractable metals. Meso-density fractions, consisting largely of aggregated clusters based on SEM observation, accounted for on average 56 %–70 % of total extractable metals and OM present in these soils. The OM in meso-density fractions showed a 2–23 unit lower C : N ratio than the lowest-density fraction of the respective soil and thus appeared microbially processed relative to the original plant material. The amounts of PP- and OX-extractable metals correlated positively with co-dissolved C across the soils and, to some extent, across the density fractions within each soil. These results led to a hypothesis which involves two distinct levels of organo-metal interaction: (1) the formation of OM-rich, mixed metal phases with fixed OM : metal stoichiometry followed by (2) the development of meso-density microaggregates via “gluing” action of these organo-metallic phases by entraining other organic and mineral particles such as phyllosilicate clays. Given that OM is mainly located in meso-density fractions, a soil's capacity to protect OM may be controlled by the balance of three processes: (i) microbial processing of plant-derived OM, (ii) dissolution of metals, and (iii) the synthesis of organo-metallic phases and their association with clays to form meso-density microaggregates. The current hypothesis may help to fill the gap between well-studied molecular-scale interaction (e.g., OM adsorption on mineral surface, coprecipitation) and larger-scale processes such as aggregation, C accrual, and pedogenesis.

The results of long-term experiments (LTEs) performed at the Geographical Network of experimental stations encompassing major soil types in Russia (soddy-podzolic (Retisols, Luvisols, and Podzols); gray forest (Luvic Greyzemic Phaeozems); leached, typical, and southern chernozems (Chernozems); chestnut soils (Kastanozems); meadow brown soils (Albic Stagnic Luvisols); and meadow chernozem-like soils (Luvic Greyzemic Stagnic Phaeozems)) within the entire country (from the north to the south of the European part of Russia, Siberia, and the south of the Far East region (Amur oblast, Khabarovsk, and Primorskii regions)) are summarized. Most of the stationary LTEs were lasting 20–45 years; ten LTEs lasted from 50 to 81 years. It was found that the organomineral fertilizer system (OMFS) exceeded the mineral fertilizer system (MFS) in its effect on the yield by 1–40% in 18 experiments, while the MFS was more efficient than the OMFS by 2–3% in only three LTEs. For the same soil type, the differences in Corg content between unfertilized trials reach 0.56–1.55% for soddy-podzolic soils and 1.58–3.93% for chernozems. Differences in soil Corg content between the unfertilized and OMFS (manure + NPK) trials were less than 10% in four LTEs, 11–20% in six LTEs, and >20% in ten LTEs; the average difference reached 0.27% of Corg. The levels of minimum (Cmin) and optimum (Copt) organic carbon content have been determined with due account for the soil types, soil texture classes, and the applied fertilizer system. They can be used as reference values for the studied soils.

The soils of Chernevaya taiga are unique in terms of high fertility that was formed not as a result of agricultural practices, but due to the combination of a huge volume of biotic and abiotic resources. This area was able to preserve its “pre-agricultural” level of fertility overtime by avoiding the negative consequences of long-standing agricultural usage. Comprehensive analysis of all related properties within the framework of a metagenomic study and identification of microbial drivers of fertility can become the basis for innovative technologies aimed to increase the productivity of soils and crops. In this work, for the first time were obtained data on the taxonomic structure and features of the of the microbiota of soils in the Chernevaya taiga and identified taxa, the number of which significantly increases with the transition from the background zonal soil to the soil of Chernevaya taiga. Analysis of soil samples collected during expeditionary surveys in 2019 showed that the soils in the Western Siberia (Novosibirsk, Tomsk, Kemerovo, and Altai regions) portion of the Chernevaya taiga are texture-differentiated dark gray soils (clay loam and silt clay varieties confined to the deluvial cover of the Holocene and Late Pleistocene) that were formed as a result of a unique combination of geogenic and bioclimatic conditions. These soils are not affected by the permafrost in winter timers and are supplied with enough moisture to precipitate rapid mineralization of litter material and the fixation of mineral nutrients in the upper humus layer of the soil profile. The accumulation of nutrients is an essential property of the soils of the Chernevaya taiga associated with the phenomenon of gigantism and extremely high levels of plant productivity. The soils of Chernevaya taiga contain the maximum amount of carbon in organic compounds compared with soils of oligotrophic habitats (9.85% versus 2.74%). The levels of actual soil fertility in the soils of the Chernevaya taiga are several times higher than in the soils of adjacent biotopes (the maximum content of the exchange forms of phosphorus and potassium is 702 and 470 mg/kg), which, when compared to oligotrophic forests, are poor in terms of agrochemical fertility (the maximum content of the exchange forms of phosphorus and potassium is 113 and 18 mg/kg), do not have a pronounced humus profile and are either gray-humus (Umbrisol) or Podzol types according to substantive-profile classification of Russian soils. The diversity of microorganisms in the studied soils varies depending on the trophic regime of the ecosystem. The soils of the Chernevaya taiga are characterized by an increased diversity of the microbial community (estimated by the Shannon index), as well as by presence of phyla Nitrospirae and Thaumarchaeota, that, however, are not dominant. Phyla Proteobacteria, Verrucomicrobia, Actinobacteria, Acidobacteria, Planctomycetes, Firmicutes appeared to be common for all studied soils.

In the course of studies in typical forest ecosystems of the northern, middle, and southern taiga of Western Siberia performed at the peak of the growing season, the spatial variation of soil CO2 emissions and their relationships with the content of extractable and microbial soil carbon and soil hydrothermic parameters were estimated. The studied parameters of the soil carbon cycle are characterized by the high spatial variability in all the studied ecosystems. This fact indicates the need for a detailed investigation of the greenhouse gas soil emission in all ecosystems typical of a given natural zone. There is a statistically significant difference between the soils of the green-moss pine forests and the soils of the lichen pine forest of the northern taiga. In the green-moss pine forest, the carbon content of microbial biomass is 1.5 times higher (195 ± 24 and 127 ± 16 mg C/kg soil, respectively), the content of extractable carbon is 4 times higher (157 ± 25 and 41 ± 5 mg C/kg of soil, respectively), and the CO2 emission is 1.7 times higher (324 ± 20 and 190 ± 10 mg CO2/(m2 h), respectively) than those in the lichen pine forest. In the northern taiga zone, carbon dioxide emissions from soils in the green-moss pine forests are largely determined by the soil temperature; the role of soil moisture is less significant. In the soils of lichen pine forests, the CO2 emission is mainly controlled by the content of extractable carbon. Significant factors influencing the soil СО2 emission in forest ecosystems of the taiga zone are the content of extractable and microbial carbon and hydrothermic parameters of the soils.

The existing classifications of soil texture are based on the sedimentation data. The aim of this article is to consider the ways to develop soil textural classification on the basis of particle-size distribution (PSD) data obtained by the laser diffraction method. A detailed comparison of PSD data obtained by the classical pipette method and the method of laser diffractometry has been performed. We have shown the reproducibility of the laser diffraction method and the effect of the oxidation stage on the soil texture class. This study is based on eight genetic soil types (overall, 32 full-profile soil pits) forming a zonal soil sequence from Podzols (Subpolar Urals) to ferrallitic soil (southwest Oceania) and differing in their mineralogical compositions, textures, and elementary pedogenetic processes. The direct use of the Kachinskii and USDA classifications with the data of the laser diffraction method leads to mistakes in determining the soil texture class in 43 and 65% of cases, respectively. The increasing complexity of recalculation, introduction of new variables, and accounting for interlaboratory errors allow us to determine correctly the texture class according to the Kachinskii and USDA classifications in no more than 70 and 72% of soil samples, respectively. The most simple and effective approach to solve the classification problem for the laser diffraction method is to calibrate existing classifications directly on the basis of data on soil samples, for which the texture class was determined by the field method.

We have carried out a field experiment to study the migration of Ni, Cu, and Co from the organic horizon of Al–Fe-humus podzols polluted with heavy metals (HMs) to the dominant species of dwarf shrubs, mosses, and lichens forming the ground vegetation layer in middle-aged pine forests. The following hypotheses were tested: (1) the introduction of metallurgical dust causes destruction of ground vegetation layer even in the absence of sulfur dioxide; (2) the destruction of this layer is caused by high concentrations of HMs in the aboveground organs of plants and lichens, which lead to their death; and (3) the level of HM accumulation by different taxa is directly correlated with their strategy of mineral nutrition. The contents of Ni, Cu, and Co in the organic horizon of podzols and in the assimilatory organs of dominant dwarf shrub, moss, and lichen species were determined by atomic absorption spectrometry. High inter- and intracenotic variation in the level of HM pollution of the soil organic horizon was revealed, which caused spatially uneven destruction of the ground vegetation layer. The translocation of HMs from the polluted soil to the aboveground parts of plants and lichens leads to a 1.5- to 5-fold increase in the content of HMs in all species, which does not exceed the toxicity threshold and does not prevent their growth in the experimental plots. The introduction of metallurgical dust over 5 years made the level of pollution of the organic soil horizon comparable to that in the buffer zone of the Severonikel Plant. This made it possible to compare the HM content in plants and lichens under the conditions of soil and aerotechnogenic pollution and determine the features of HM accumulation by organisms with different strategies of mineral nutrition. The Ni < Cu concentration ratio in the organic soil horizon is reversed in the leaves of dwarf shrubs and green and brown parts of moss Pleurozium schreberi under conditions of either soil pollution and aerotechnogenic pollution.

Materials of engineering-ecological researches on various economic objects in Udmurtia are processed and systematized. Average (background) concentration of the heavy metals which are subject to obligatory control at engineering-ecological researches (lead, cadmium, zinc, copper, nickel, arsenic, mercury) for the main associations of soils and most wide-distributed kinds of soils are defined. It is revealed that with decreasing the soil’s podzol content and increasing the soil’s clay content, concentrations of heavy metals naturally raise. In general, similar soils are characterized by similar concentrations of heavy metals and similar ratios of concentration. It is established that excesses of hygienic standards on such elements as nickel, arsenic and to a lesser extent zinc, copper and cadmium, are not only something exclusive in Udmurtia, but also spreading more and more widely, especially in soils of light structure. The received average concentration can be accepted as background one at the subsequent engineering-ecological researches in the region.

The extent of microbiological processes in soil is determined not only by the number of microorganisms, but mainly by their activity. Therefore, it is extremely relevant to study the influence of various organic, mineral fertilizers, lime used for the cultivation of gley-podzolic soils of the Far North, on the change of intensity and development of the most important microbiological processes in these soils. In its natural state, soils are a multi-component system consisting of many heterogeneous microenvironments inhabited by microorganisms with different food chains. In anthropogenic activities, and in particular, in the introduction of organic and mineral fertilizers, the environmental conditions in soils change significantly, leading to a significant adjustment in taxonomic structure of microbial cenoses and their functional activities. Particularities of soil-climatic conditions also significantly affect species composition and features of functioning of microbocenoses in soils. Therefore, when choosing the most effective methods of soil cultivation in each particular climate zone, a lot of attention is paid to their biological assessment. The studies show that fertilizer and lime has a positive effect on the prokaryote complex of soil microorganisms of everfrozen soils. Keywords: Everfrozen soils; Fertilizers; Peat; Manure; Lime; Bacteria; Fungi; Soil enzymes References Arinushkina E.V. (1970). Manual for the chemical analysis of soils. Moscow: Publishing house Mosk. University, 487 p. Babeva I.P., Chernov I.Yu. (1982). Yeast in the tundra soils of Taimyr. Soil Science. No. 10, pp. 60-64. Great Workshop on Microbiology (1962). Ed. G. L. Seliber. M. Higher school. 492p. Bunnell F.I., Miller A.K, Flanagan P.W & Bennoit K.F. (1980). The microflora: composition, biomass and environmental relation. An arctic ecosystem: (The coastal tundra at Barrow, Alaska) Ed.J. Brounet al. - Stroudsburg (Pennsylvania), pp: 255-290. Voznyakovskaya Yu.M., Kulikova A.S. (1955). 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Microorganisms and agricultural productivity. M, 343 p. Mishustin, E.N. (1975). Association of soil microorganisms. M, Science. Pp. 114-120. Pectolytic enzymes of microorganisms. (1971). V.I.Smirnov, V.V. Kotelev. Academy of Sciences of the MSSR. Dept. microbiology. Chisinau, 35 p. Polyanskaya L.M., Lukin S.M. & Zvyagintsev D.G. (1997) Changes in the composition of microbial biomass in soil during cultivation Pochvovedenie. 2, 206-212. Polyanskaya L.M., Golovchenko A.V. & Zvyagintsev D.G. (1998) Determination of the viability of spores and mycelium of fungi in the soil. Microbiology. 67(6), 832-836. Polyanskaya L.M., R.B. Gorodnichev, & D.G. Zvyagintsev (2013). Sizes of bacteria cells in soils, determined by the method of "cascade" filtration. Izvestia RAN. Biological series. 2, p. 14. DOI: 10.7868 / S00023329130101284–151 Stepanova L.N. (1959). Influence of long-term use of mineral fertilizers on the content of toxic bacteria in sod-podzolic soils. // Scientific. doc. higher. schools. Biol. Science. 3, 243-247. Chunderova A.I. (1973). Enzymatic activity of soddy-podzolic soils of the North-West zone: abstract of Ph.D. dis. Dr. Biol. sciences . Tallinn. 46 p.

A combined analysis of the current climate trends and the dynamics of soil respiration under soddy–weakly podzolic sandy-loamy soil (Entic Podzol (Arenic)) in the forest and meadow cenoses in the Prioksko-Terrasny Biosphere Reserve (southern part of the Moscow oblast) is performed. During the observation period (1998–2018), distinct trends of an increase in the average annual air temperature (Tair) and aridity of the summer season as well as a decrease in the duration of stable snow cover are observed. A general trend of a decrease in the total CO2 fluxes from the Entic Podzol (Arenic) under a forest and a meadow for all seasons of the year and throughout the year is also observable on this background. The linear trends of a decrease in the annual and fall seasonal CO2 fluxes from the soils in both cenoses are statistically significant (P < 0.05). Over the 21-year observation period, the monthly average CO2 fluxes from soils have tightly correlated with the average monthly Tair (r = 0.78–0.84, P < 0.001). In dry years, the temperature sensitivity of soils expressed via the Q10 coefficient is by 10–12% lower, than in the years with normal moistening. The average long-term values of annual soil respiration (AnSR) in the forest and meadow cenoses amount to 581 ± 54 and 727 ± 71 g C/(m2 year), respectively, with an interannual variation of 20–22%. The AnSR and summer hydrothermal coefficient are the most closely related explaining 51–56% of the variance in annual CO2 fluxes from soils. The warm season (May–October), which coincides with the period of active plant vegetation, accounts for 73–77% of the AnSR. However, the share of the cold season (November–April) in the annual CO2 flux from soils may reach 38–39% in individual years. Expansion of the network of stationary long-term year-round monitoring of soil respiration is a necessary condition for obtaining both more realistic estimates of the CO2 fluxes from soils and predictions of the ecosystem responses to the current and future climate changes.

Background: There is considerable uncertainty about the actual size of the global soil organiccarbon (SOC) pool and its spatial distribution due to insufficient and heterogeneous data cover-age. Aims: We aimed to assess the size of the German agricultural SOC stock and develop a stratification approach that could be used in national greenhouse gas reporting. Methods: Soils from a total of 3104 sites, comprising 2234 croplands, 820 permanent grasslands and 50 sites with permanent crops (vineyards, orchards) were sampled in a grid of 8 x 8 km to a depth of 100 cm in fixed depth increments. In addition, a decade of management data was recorded in a questionnaire completed by farmers. Two different approaches were used to stratify cropland and grassland mineral soils and derive homogeneous groups: stratification via soil type (pedogenesis) and via SOC-relevant soil properties. Results: A total of 146 soils were identified as organic soils, which stored by far the highest average SOC stock of528–201 Mg ha–1 in 0–100 cm depth. Of the mineral soils, croplands and permanent crops stored on average 61–25 and 62–25 Mg ha–1 in 0–30 cm (topsoil) and 35–30 and 44–28 Mg ha–1 in 30–100 cm (subsoil), while permanent grasslands stored significantly more SOC (88–32 and 47–50 Mg ha–1 in topsoil and subsoil). Overall, topsoils stored 67–14% and subsoils 33–14% of total SOC stocks. Soil C:N ratio, clay content and ground-water level were major factors that explained the spatial variability of SOC stocks in mineral soils. Accordingly, Podzols, Gleysols and Vertisols were found to have the highest SOC stocks. Conclusions: Stratification via soil properties yielded the most comparable cropland and grassland strata and is thus preferable for estimating land-use change effects, e.g., for greenhouse gas inventories. In total, 2.5 Pg C are stored in the upper 100 cm of German agricultural soils, making them the largest organic carbon pool in terrestrial ecosystems of Germany. This bares a large responsibility for the agricultural sector and society as a whole to maintain and, if possible, enhance this pool.

The mobility of Cd, Co, Cu, Ni, and Zn in podzols and organic soils (Histosols) in the area of long-term pollution from the Monchegorsk copper–nickel plant (Murmansk oblast, Russia) has been assessed using the parameters of diffusion and convection–diffusion models. The found values of diffusion parameters match the data for other regions. In most cases, the convective flow of heavy metals is directed downwards and has a velocity of 0.126 to 0.31 cm/yr, or it does not differ from zero in a statistically significant manner. On the average, podzols and organic soils are similar in the diffusion parameters with regard to the total heavy metal content but differ in the velocity of convective transfer, which is much slower in organic soils. The model estimates for the inflow of heavy metal pollutants to soil do not depend on the distance from the plant, although a correlation with soil type is observable: an additional lateral influx of heavy metals to the surface most likely takes place in organic soils, associated with local depressions. An insufficient sample volume does not permit to assess the correlation of migration parameters with soil properties, while their correlation with chemical mobility (extraction with ammonium acetate buffer) appears as an insignificant trend.

Soil temperature was measured in the O horizon of Albic Podzol on two sites of strongly contaminated and damaged ecosystem from September 22 to July 10 in 2014/2015 and 2015/2016. The ecosystem is located 8 km to the north of the Severonikel industrial complex (the Kola Peninsula), the largest source of emissions of SO2 and heavy metals in Northern Europe. The aim of the study was to compare temperature regimes of technogenic barren soil without vegetation, which predominates in the ecosystem, and under a small group of depressed crowberry (Empetrum hermaphroditum) developing in the area in response to a decrease in the emissions from the Severonikel industrial complex. The results attest to significant differences between temperature parameters of the two sites. The soil under crowberry was characterized by significantly smaller temperature fluctuations during the entire period of observations and in the daily cycle. In autumn, the dwarf shrub maintained soil temperatures above zero for a longer period and mitigated first night freezing. Because of the dark color of the degrading O horizon of technogenic barren, this soil was characterized by higher daytime and mean daily temperatures in summer. In autumn, before the formation of a permanent snow cover, the soil of the barren site was subjected to stronger freezing in response to sharp decrease in the air temperature. Thus, even a depressed ground vegetation protects the soil from strong temperature fluctuations and ensures more stable conditions for the plant growth. The absence of the ground vegetation results in stronger soil drying in summer and in a sharper decrease in soil temperature in autumn. The soil overheating and strong drying in summer and the soil freezing in autumn can act as stress factors in addition to extreme contamination of the damaged ecosystems near the emission source for the survived trees and their seedlings.

The water-soluble components originated in coniferous litters desorb into solution the native organic substances from the solid phase of the eluvial horizons of podzols and podzolic soil. In podzols, the water-soluble organic matter (WSOM) extracted from litter and then passing through the E horizons are sorbed by the BFH horizons if their concentration in solution exceeds 35 mg C/L. The sorption ranges from tens to hundreds of milligrams of carbon per kilogram of the BFH horizon. The WSOM can be sorbed by the BT horizons of podzolic soil when the concentration of organic substances in the liquid phase is higher than in podzols. The model experiments with minerals show that kaolinite and illite interact with the soluble substances percolating from the litter and selectively extract more hydrophilic and less aromatic components with relatively low molecular weights. On the contrary, goethite interacts with the WSOM prevalently sorbing hydrophobic components, substances of phenolic nature, components enriched in aromatic carbon, and substances with molecular weights less than 7 kDa. The spectral characteristics of WSOM change after the sorption interaction with minerals: the fluorescence associated with the humus substances with the longest conjugation chain decreases or disappears, while new fluorophores containing fragments of phenolic and/or protein structures emerge. The presence of kaolinite and illite in the eluvial horizons and their interaction with WSOM most likely contribute to the transformation of WSOM composition and appearance of the properties maximally favorable for their sorption on iron hydroxides in the lower horizons.

Estimates of the spatial heterogeneity of the organic matter distribution in forest soils determined by the influence of the species and spatial structure of phytocenoses are relevant for many environmental problems, including the calculation of carbon sinks and modeling of the dynamics of forest ecosystems. We analyzed the data on the organic carbon (Corg) and total nitrogen (Ntot) contents in the O (forest litter) and AY (humus) horizons of Entic Podzols in the Prioksko-Terrasnyi Reserve (54.89° N, 37.56° E). The studied site is located in a coniferous–deciduous forest formed after overgrowing of the cutting area of pine stands. We sampled the O and AY horizons along transects between trees of different species, i.e., near the trunks, under the crown, and in the intercrown space. The contents of Corg and Ntot in the O horizon varied within 17.6–44.9 and 0.84–1.79%, respectively. The ranges for the AY horizon were greater: 0.71–8.5% (Corg) and 0.035–0.33% (Ntot). The relationship between the contents of Corg and Ntot in the O and AY horizons was close to linear (rs = 0.72 and rs = 0.96, respectively). We also obtained similar C : N ratios for the both horizons. The litter thickness and the content of Ntot in the O horizon, as well as the content of Corg in the AY horizon, significantly differed in different parts of the transects (P < 0.05). The differences in the litter thickness and the Corg content in the O horizon under the crowns of different tree species were also significant. In samples from the AY horizon taken in intercrown spaces, the Ntot content correlated with the demand of plant species of the ground cover for soil fertility. The data obtained reflect the influence of specific features of spatial patterns of surface and root litterfall in multispecies communities of mixed forest stands on the spatial variability of Corg and Ntot contents in soil.

Temperatures of sandy podzols of middle taiga pine forests with moss and lichen ground cover were analyzed which had been exposed to ground fires of low to medium intensity. In general, temperatures in lichen and moss plots of the pine forests under study, are close to each similar, but in the first year after a fire a noticeable contrast was observed. The reasons are an increase in the amplitude of daily temperatures on the soil surface and stronger heating of upper mineral layers. Temperatures in the mineral layer with depths up to 30 cm depend on the thickness of the forest floor. Analysis of the results show that the duration of post-fire effects in pine forests with sandy podzols is determined by a number of factors: the intensity of the fire, the degree of erosion of the ground cover and litter, and the recovery rate of these components.

This study presents a genetic characteristic of iron-illuvial podzols formed on an esker composed of coarse-grained and medium-grained sands, including the gravel–pebble fractions with boulders. We have revealed quantitative differences in the composition and properties of iron-illuvial podzols on the esker as compared to iron-illuvial podzols formed on sandy moraines under similar bioclimatic conditions. These differences are related to the topography and specific lithological composition of rocks in the esker. Fluvioglacial deposits are usually described without their specification into intraglacial deposits, forming esker, and periglacial deposits formed beyond the glacier. However, this is insufficient, taking into account the differences in the topography and rocks of eskers.

The content and profile distribution of 137Cs in iron-illuvial dwarf and shallow-podzolic podzols (Albic Podzols) under bilberry-lichen and green-lichen-bilberry pine forests in the located near the Kola Nuclear Power Plant have been analyzed. The pollution density (reserve) of 137Cs in the root-inhabited layer (0–30 cm) in the studied soils was significantly lower than the established control level of 37 000 Bq/m2 and amounts to 530–2459 Bq/m2. A significant part of 137Cs (60 to 90%) was concentrated in mineral horizons. It has been shown that the pollution density of 137Cs in the observation zone of a nuclear power plant was mainly due to global fallout. The greatest influence on 137Cs accumulation in the studied soils was exerted by the organic matter reserve.

This paper aimed to characterize urbostratozems (Urbic Technosol, WRB) of Saint Petersburg located in industrial (“Electrodepo” railway station) and residential (region Polish Garden) zones. These soils were also compared with background (natural) soddy podzol soil (Umbric Albic Gleic Podzol, WRB) sampled in recreational zone (suburban park “Oranienbaum”). Soil samples were collected from soil horizons for chemical analysis and from top of soils for microbialogical analysis in June of 2012. Chemical properties (pH, total organic carbon, mobile forms of K and P) and content of heavy metals (Pb, Cu, Zn, Ni) in soils were determined. Culturable forms of microorganisms (bacteria and fungi) were studied. Assessment of the enzymatic activity of the soil was carried out by culturing of microorganisms-producers of protease, amylase, cellulase and lipase on special media. Biotesting using cress (Lepidium sativum L.) seeds had been carried out for assessment of soil phytotoxicity. It was found that chemical properties of urban and natural soils differ greatly. Heavy metal pollution was evident in both urban soils, but maximum concentrations of heavy metals were found in the soil of the industrial zone. Phytotoxocity had been also most pronouncend in the soil of the industrial zone. The natural soil exhibited significantly higher respiration activity than urbostratozems. The greatest difference in the structure of the bacterial and fungal communities was observed between the natural soil of the recreational zone and the urbostratozem of the industrial zone. Algae had been present in the urban soils of the residential zone that was not observed in the natural podzol. The minimum number of producers of all enzymes, except for cellulase, was observed in the soddy podzol in the recreational zone. The maximum number of protease and amylase producers was found in the soil of the industrial zone. Lipolytic activity was almost the same in all samples. It was found that more sensitive biological methods are needed for environmental assessment of urban soils. The results of the article can be used by soil scientists and environmental engineers for a comprehensive environmental assessment of the condition of urban soils and for creating new urban green spaces.

The composition of water-soluble organic matter (WSOM) of coniferous- deciduous, coniferous, and moss litter was studied. Litter type affects the composition of WSOM. Sphagnum litter contains less N and dissolved organic carbon (DOC), but more carbohydrates, the WSOM from this litter is characterized by the lowest extinction coefficients Е254. WSOM from mixed litter with a predominance of birch litter had a maximum content of N and a small amount of soluble phenolic (SP) substances. WSOM from litter of pine needles differ from the rest by having a lower content of carbohydrates, the maximum amount of SP and hydrophobic fractions. All investigated WSOM were characterized by high rates of decomposition: half-decomposition time of their stable fractions was 2–4 months. WSOM from pine litter at pH ~ 6.5 were absorbed by the BF horizon of iron–illuvial podzol, starting from the concentration of DOC of 100 mg/L. Substances from birch–spruce litter were adsorbed insignificantly under similar conditions.

The changes in the total soil carbon storage and the pools of labile and potentially mineralizable organic matter in Entic Folic Podzols of the Khibiny Mountains (Murmansk region, NW Russia) caused by wildfires of high and moderate intensity and during the post-fire succession are discussed. Although a moderate-intensity wildfire has no statistically significant impact on the total soil carbon pool, it triggers the active erosion processes leading to the carbon losses comparable to the direct pyrogenic carbon losses in a high-intensity fire. In the postfire soil restoration, the type of organic carbon accumulation changes: the surface carbon accumulation in the form of peat is characteristic of the control site, while up to half of soil carbon is accumulated in the mineral horizons at late stages of the postpyrogenic succession. A high-intensity fire leads to almost complete destruction of labile, microbial, and potentially mineralizable carbon pools in both the organic (pyrogenic) and mineral horizons. A moderate-intensity fire does not cause any statistically significant changes in these pools as compared to the control. The restoration dynamics of the labile and potentially mineralizable pools of organic matter in the pyrogenic horizons of soil differ: the trend of a steady increase in the pools of labile and microbial carbon is observed for three years after the fire and later, while the pool of potentially mineralizable carbon reaches its maximum three years after the fire and then becomes stabilized at this level.

Long-term research data have been used to compile a soil map of the most transformed part of the gas-condensate field in the Middle Angara region. The studied area is assigned to the North Baikal mountainous province with podzolic (Podzols), soddy-podzolic (Retisols), peat-podzolic (Histic Podzols), peat-cryozemic (Histic Cryosols), gray-humus (Cambisols), and dark-humus (Phaeozems) soils. The natural diversity of the soil cover and the content of macro- and microelements in soils have been determined. In soils near some gas-condensate field facilities, the contents of oil products, lead, zinc, nickel, and chrome exceed the background values and health and safety standards. The chemical composition of soil water in the area has changed, and chloride soil salinization is recorded. Ecological zoning of the area with respect to its significance for humans and ecosystems and soil susceptibility to anthropogenic loads has been performed. A larger part of the gas field is suitable for the development, except for permafrost taiga areas, valuable virgin landscapes, and vulnerable soils of steep slopes. The zone requiring rehabilitation measures with subsequent extensive use includes the areas with strongly disturbed ground cover and the sod layer.

Immobilized metal affinity chromatography (IMAC) has been used to fractionate organic compounds in alkaline extracts from forest soils of the Komi Republic by their ability to form complexes with copper ions. An algorithm for chromatographic fractionation of substances into the groups of homogeneous molecular compounds is proposed by selecting the separation conditions; this algorithm comprises sequential change in pH and ionic strength of the eluent. As is shown, the alkaline extract contains three fractions, the components of which differ in their ability to form complexes with copper. The humic substances of iron-illuvial podzol (Albic Podzol), podzolic (Glossic Retisol), and peaty-podzolic gleyic (Histic Retisol) soils are shown to differ in their relative contents of ligand-forming organic compounds. The maximum content (according to Corg) of copper complexones is recorded in the organic matter of forest litters of the examined soils (14–21 g/kg). The corresponding values of the organic matter content in the eluvial horizons are 0.5–1.5 g/kg. The highest content of the carbon compounds able to bind copper ions is characteristic of podzolic soils, while the organic matter components of podzols and peaty-podzolic gleyic soil display somewhat lower affinity for copper. The proposed algorithm can be used to assess the soil vulnerability to heavy metal pollution.