Genetic features of soils in altitudinal natural zones of the Khibiny Mountains

The plant cover of the Khibiny Mountains is characterized by the well-pronounced altitudinal zonality: high-alpine barrens—lichen, dwarf shrub, and shrub tundra—elfin birch forest—spruce forest. Humic petrozems (Lithic Leptosols) under sparse vegetation are formed on the tops of the mountains. The soils of the tundra zone are represented by podburs on the eluvium of nepheline syenite; smaller areas are occupied by typical cryozems. Humus-illuvial podzols are developed from moraine deposits under elfin birch forests and open spruce woodland. The moraine deposits in the inner valleys of the Khibiny Mountains are enriched in the products of weathering of nepheline syenite. The humus-illuvial podzols developed from them differ from their analogues on plain territories in the higher humus content and less contrasting eluvialilluvial differentiation.     

Zonal features of Al-Fe-humus pedogenesis on moraine deposits in the Kola Peninsula

Zonal differences in the genetic features of Al-Fe-humus podzols developed from moraine deposits in the tundra, forest-tundra, and northern taiga zones are revealed. The coefficient of profile differentiation of podzols with respect to the bulk content of aluminum increases from the tundra (1.16) to northern taiga (1.33); the analogous coefficient calculated with respect to the bulk content of iron increases in the same direction from 1.63 to 3.73. The zonal differences related to the contents of the amorphous forms of aluminum and iron are more contrasting: the coefficients of the profile differentiation increase from 4–6 in the tundra to 20–39 in the taiga. Differences in the humus contents of podzols developed in different natural zones are mainly seen in the podzolic horizon.     

Comparative Analysis of the Number and Structure of the Complexes of Microscopic Fungi in Tundra and Taiga Soils in the North of the Kola Peninsula

The number, biomass, length of fungal mycelium, and species diversity of microscopic fungi have been studied in soils of the tundra and taiga zones in the northern part of the Kola Peninsula: Al-Fe-humus podzols (Albic Podzols), podburs (Entic Podzols), dry peaty soils (Folic Histosols), low-moor peat soils (Sapric Histosols), and soils of frost bare spots (Cryosols). The number of cultivated microscopic fungi in tundra soils varied from 8 to 328 thousand CFU/g, their biomass averaged 1.81 ± 0.19 mg/g, and the length of fungal mycelium averaged 245 ± 25 m/g. The number of micromycetes in taiga soils varied from 80 to 350 thousand CFU/g, the number of fungal propagules in some years reached 600 thousand CFU/g; the fungal biomass varied from 0.23 to 6.2 mg/g, and the length of fungal mycelium varied from 32 to 3900 m/g. Overall, 36 species of fungi belonging to 16 genera, 13 families, and 8 orders were isolated from tundra soils. The species diversity of microscopic fungi in taiga soils was significantly higher: 87 species belonging to 31 genera, 21 families, and 11 orders. Fungi from the Penicillium genus predominated in both natural zones and constituted 38–50% of the total number of isolated species. The soils of tundra and taiga zones were characterized by their own complexes of micromycetes; the similarity of their species composition was about 40%. In soils of the tundra zone, Mortierella longicollis, Penicillium melinii, P. raistrickii, and P. simplicissimum predominated; dominant fungal species in soils of the taiga zone were represented by M. longicollis, P. decumbens, P. implicatum, and Umbelopsis isabellina.     

Fertility of soils under spruce forests of the Khibiny Mountains

The development of fertility of soils on different parent rocks is considered for different types of spruce forests in the Khibiny Mountains. The spruce forests of Mts. Kuel??por, Vud??yavrchorr, Chil??mana, and Saami were the objects for the study. The results showed that the fertility level of the soils of the Khibiny Mountains was determined by the combined influence of the parent rock??s composition and the vegetation. The differences in the soil properties are mainly explained by the composition of the parent rocks. The pod-burs differ from the podzols by the higher contents of organic matter, nitrogen, and available nutrients. The podzols are the most acid soils there. The podburs of Mt Kuel??por developing on base-rich parent rocks are the most fertile. The differences in the fertility of the soils on the intrabiogeocenotic (tessera) level are related to the vegetation. The soils of the spruce and tall-grass tesseras are richer in nitrogen, calcium, and manganese as compared to the soils of the dwarf shrub-green moss, low-grass-dwarf shrub-green moss, and tussock grass-dwarf shrub tesseras.     

Zonal features of humus formation in Al-Fe-humus podzols of the Kola Peninsula

Natural zonality manifests itself clearly in the territory of the Kola Peninsula: subzones of southern tundra, forest-tundra (sparse birch forest), and northern taiga replace one other from the north, to the Barents Sea coast, and to the south. Sandy and sandy loamy sediments of glacial, marine, and glaciofluvial origin are parent rocks all over the territory. Al-Fe-humus podzols, the profile of which is characterized by clear differentiation of the chemical composition and organic matter content, were formed on these rocks. There is almost no difference in the particle-size and total chemical composition of the podzols, whereas the content and composition of the humus in the soils of different zones differ significantly, and this is especially obvious in the illuvial horizon. As the climatic severity increases, the humus content in the mineral profile and the organic matter enrichment with nitrogen increase.     

Ecophysiological Characteristics of Psychrotolerant Actinomycetes in Tundra and Forest Landscapes

Eurasian Soil Science - Actinomycetic complexes of soils and plant substrates from tundra and taiga zones of Russia and Finland have been studied. A molecular cytogenetic...     

Soil cover patterns and land assessment in the Baikal region of Buryatia using the example of the Kabansk district

The soil cover patterns in the Kabansk district (the Baikal region of the Buryat Republic), including the Selenga River delta, are analyzed. A soil map of this area has been developed on a scale of 1 : 500000. Stony organic soils are widespread in the tundra zone. Mountain-meadow soddy soils and tundra podburs (under dwarf pine) are formed at lower heights around lakes and in glacial valleys. Kabansk district includes taiga landscapes on the northern slopes of the Khamar-Daban Ridge with the predominance of podburs, podzols, soddy-taiga soils, and burozems. Agrolandscapes occur in the Nizhneselenginsk meadow-bog and forest-steppe natural region with a predominance of soddy forest, soddy gray forest, meadow, alluvial, meadow-bog, and bog soils. Data on the land evaluation in the agricultural part of the studied region are given.     

Genetic specificity and geography of taiga soils in the central part of the Baikal region

A specific feature of the development of automorphic taiga soils in the Baikal region is the lack of correspondence between the weak intensity of the soil chemical weathering and the high intensity of the removal of alkaline-earth elements from the soil profile in the form of suspensions. The loss of the clay fraction affects the water-physical properties of these soils and their temperature regime. The areas of different soil types in the northern and middle taiga zones have been calculated on the basis of soil maps of different scales. It is shown that podburs and acid soddy taiga soils predominate in these zones; the area of podzols, which were previously considered to be the dominant soil type in the middle and southern taiga zones, is smaller.     

Changes in carbon pool and CO<Subscript>2</Subscript> emission in the course of postagrogenic succession on gray soils (Luvic Phaeozems) in European Russia

An analogous time series of fallow ecosystems (gray soils (Luvic Phaeozems) plowed and fallowed for 2, 7, 20, 60, and more than 120 years) in the broad-leaved forest zone of Orel oblast has been analyzed. Changes in carbon pool and CO2 emission in the course of postagrogenic succession during the vegetation and winter seasons have been estimated. The restoration of ecosystems on Luvic Phaeozems follows regularities revealed in analogous studies of southern taiga Podzols and forest-steppe Chernozems. Analogously to the other studied zonal chronosequences, total annual soil respiration on Luvic Phaeozems reaches the initial level of undisturbed ecosystems simultaneously with the restoration of phytomass reserve, although significantly earlier than the organic carbon reserve in soils is restored. According to regression models, among the zonal fallows in European Russia, including the southern taiga (Podzols), mixed forests (Luvisols), broadleaved forests (Luvic Phaeozems ), forest-steppe (Chernozems) and dry steppe (Calcisol–Solonetz soil complexes), the mean annual soil respiration is maximum in the zone of gray soils and Chernozems. The increase in soil respiration under artificial wetting (Birch effect) on fallows in the broad-leaved forest zone is minimum among the studied zonal chronosequences: 1.1 ± 0.6 (no effect), which corresponds to the optimal hydrothermal conditions in this zone.     

Water-soluble low-molecular-weight organic acids in automorphic loamy soils of the tundra and taiga zones

The formation features of water-soluble low-molecular-weight organic acids (LMWOAs) in a zonal series of automorphic soils on loose silicate rocks from the middle taiga to the southern tundra (typical podzolic, gley-podzolic, and surface-gley tundra soils) were first revealed by gas chromatography mass spectrometry and gas-liquid chromatography. The content of LMWOAs varies within the range of 1–14 mg/dm³, which corresponds to 1–5% of the total carbon of the water-soluble soil organic matter. It has been shown that a subzonal feature of gley-podzolic soils in the northern taiga is the high content of LMWOAs, including primarily the strongest aliphatic hydroxyl acids. Possible mechanisms of their formation and accumulation in soils have been considered.     

Factors of the development of taiga and tundra soils with differentiation of Fe and Al oxides in the profile

Statistical data on the bulk contents of iron and aluminum oxides in iron-depleted and iron-enriched horizons of a wide range of taiga and tundra soils were compared. It was found that the soils could be arranged into the following sequence characterized by an increase in the relative contribution of iron oxides and a decrease in the relative contribution of aluminum oxides to the differentiation of sesquioxides in the soil profiles: sandy podzols—soddy-podzolic soils—loamy micropodzols and iron-illuvial svetlozems—cryogenic ferruginated gleyzems. It was concluded that the bleaching of eluvial horizons and the depletion of sesquioxides from them, as well as the accumulation of sesquioxides in the illuvial horizons, are controlled by different processes in different soils. In sandy podzols, the differentiation of sesquioxides is due to the Al-Fe-humus podzolization; in loamy micropodzols and iron-illuvial svetlozems, due to the redox-Al-Fe-humus podzolization; in podzolic and soddy-podzolic soils, due to the selective podzolization and lessivage; and, in cryogenic ferruginated gleyzems, due to the reduction-oxidation processes.     

Morphological-genetic characterization of soils on the Enganepe Ridge

Specific features of the soil formation in the Polar Urals related to the slope aspects, parent rocks, and vegetation are considered using the example of the Enganepe Ridge. Soils of the same type (humus-illuvial podburs and podzolized podburs) are formed under the severe climatic conditions of the mountain tundra belt irrespective of the slope aspect. The main differences in the prevalent soils are manifested in the mountain belt of sparse forests. Under the sparse larch forests on the southeast-facing slope, illuvial-humus-iron podzols predominate. On the south-facing slope under the sparse spruce forests, clay-illuviated illuvialhumus-iron podzols alternate with mucky-dark humus soddy lithozems. Burozems are formed in a few ecological niches. The richness of the parent rocks, along with the southern slope aspect and the transitional-accumulative nutrient transfer, is shown to promote the formation of sparse spruce forests under the climatic conditions of the Polar Urals.     

Automorphic soils of the central and southern Timan Ridge

Automorphic loamy soils developing from different parent materials in the central and southern parts of the Timan Ridge are described. Pale-podzolic soil and iron-illuvial texture-differentiated svetlozems are developed from silty covering loams underlain by moraine deposits. Podzolic, iron-illuvial, cryometamorphic, and clay-illuvial horizons are distinguished in the svetlozems; soils with such a complex morphology have been described in the taiga zone of European Russia for the first time. Humus-iron-illuvial podzols are developed from acidic slates. Raw-humus rzhavozems (iron-metamorphic soils) are developed from substrates with the high content of pebbles of mafic rocks. Such soils are typical of the middle taiga zone of Central Siberia and the south of Far East. In the northwestern part of European Russia, these soils occupy small areas.     

Soils on hard rocks in the northwest of Russia: Chemical and mineralogical properties,genesis, and classification problems

Soil formation on hard rocks—nepheline syenite, amphibolite, metamorphized gabbro diabase, and their derivatives—was studied in the mountainous tundra and in the northern and middle taiga zones of the Kola Peninsula and Karelia (in the Kivach Reserve). It was found that the soils developing from these rocks could be classified into three groups: (1) petrozems with the O-M profile (the most common variant), (2) podzols and podzolized podburs on the substrates with an admixture of morainic derivatives of acid rocks, and (3) shallow (<5–10 cm) pebbly soils on the substrates without an admixture of allochthonous material (the rarest variant). In soils of the third group, the pedogenic alteration of the mineral matrix does not result in the appearance of phyllosilicates in the fine fractions if these phyllosilicates are initially absent in the rock. In these soils, the protion of the organic matter, and binding of iron released from the weathered silicate minerals into iron-organic complexes) are virtually undifferentiated by the separate soil horizons because of the very low thickness of the soil profiles. These soils have the Oao-BHFao-M profile; it is suggested that they can be classified as leptic podburs. An admixture of morainic material containing phyllosilicate minerals favors a more pronounced differentiation of the modern pedogenic processes by separate soil horizons even in the case of shallow soil profiles; the intense transformation of phyllosilicates takes place in the soils.     

Dynamics of Soil Properties and Plant Composition during Postagrogenic Evolution in Different Bioclimatic Zones

The postagrogenic dynamics of acidity and some parameters of humus status have been studied in relation to the restoration of zonal vegetation in southern taiga (podzolic and soddy-podzolic soils (Retisols)), coniferous-broadleaved (subtaiga) forest (gray forest soil (Luvic Phaeozem)), and forest-steppe (gray forest soil (Haplic Phaeozem)) subzones. The most significant transformation of the studied properties of soils under changing vegetation has been revealed for poor sandy soils of southern taiga. The degree of changes in the content and stocks of organic carbon, the enrichment of humus in nitrogen, and acidity in the 0- to 20-cm soil layer during the postagrogenic evolution decreases from north to south. The adequate reflection of soil physicochemical properties in changes of plant cover is determined by the climatic zone and the land use pattern. A correlation between the changes in the soil acidity and the portion of acidophilic species in the plant cover is revealed for the southern taiga subzone. A positive relationship is found between the content of organic carbon and the share of species preferring humus-rich soils in the forest-steppe zone.     

Soils and the soil cover of mountainous tundra and forest landscapes in the Central Khangai of Mongolia

Specific features of the soil formation and soil cover patterns in the mountainous alpine tundra and forest landscapes of the Central Khangai Range are analyzed. It is shown that the specific mucky grayhumus permafrost-affected soils are only formed under larch forests within the tundra-alpine and forest zones. Other soils have a wider geographic area. The morphological, physicochemical, and chemical characteristics of the widespread soils are given. A medium-scale map of the soil cover patterns—soil complexes, combinations, and mosaics—has been developed for the studied area.     

Soils of northern spurs of the Cherskii Ridge in the area of the northern pole of cold: Morphology,properties, and classification

The soils in the area of the northern pole of cold located on the interfluve between the Yana and Adycha rivers within the spurs of Kisilyakh Ridge included in the mountain system of Cherskii Ridge have been studied for the first time. The profile-genetic approach has been applied to describe the soils and determine their classification position. It is found that the major soil types in this region are the soils of the postlithogenic trunk belonging to the orders of lithozems (Cryic Leptosols), gley soils (Gleyic Skeletic Cryosols), and Al–Fe-humus soils (Spodic Skeletic Cryosols). The ecological ranges of altitudinal zones— the taiga zone with various types of lithozems below 630–700 m a.s.l. and the tundra zone with combinations of gley and nongley cryogenic soils above these heights—have been established. The development of gley or nongley soils is specified by the local orogenic and lithological conditions and slope aspect, which, in turn, control the degree of drainage and the presence and character of permafrost. In the profile of mountainous gley soils (gleyzems) with shallow ice-rich permafrost, cryogenic processes and features typical of the analogues of these soils on plains—cryogenic cracking, cryoturbation, solifluction, thixotropy, oxiaquic features above permafrost, saturation of the soil profile with mobile humus, etc.—are typical.     

Soil mesofauna of taiga burozems

In the burozems of the plains, the composition of the invertebrates and saprophages (the prevailing primary destroyers) differed from that in the mountainous soils only by the absence of millipedes of the Geophilomorpha order. At the same time, the differences in these characteristics between the burozems and soddypodzolic soils of the neighboring coniferous-broad-leaved forests were more significant: in the latter, the composition of the ecological groups of earthworms was more diverse. Among the earthworms, secondary destroyers (detritophages) consuming well-decomposed residues of plants and animals predominated: Aporrectodea caliginosa, A. rosea, and Octolasium lacteum. In the taiga burozems, among the secondary destroyers, very few O. lacteum among the earthworms, and Polyzonium germanicum among the millipede diplopods were found. Primary destroyers that only comminute plant tissues (Dendrobaena octaedra and Dendrodrilus rubidus f. tenuis) were the main representatives in the invertebrate population of these soils. The differences also concerned the group composition and the proportion between the life forms of the earthworms. In the southern taiga burozems, only the litter (Dendrobaena octaedra and Dendrodrilus rubidus f. tenuis) earthworms and species of the upper soil layer (Octolasium lacteum) were present. In the mountainous burozems of the Transcarpathian region, litter inhabitants (Dendrobaena attemsi and Aporrectodea submontana), soil-litter inhabitants (Dendrobaena alpina—Transcarpathian region), and inhabitants of the upper (Helodrilus cernosvitovianus) and middle (Aporrectodea carpathica and A. sturanyi) soil layers (in the Primorskii region, only the soil-litter Eisenia nordenskioldi) were identified. In the soddy-podzolic soils, dwellers of the middle soil layers (Aporrectodea caliginosa, A. rosea, and Lumbricus terrestris) were constantly present along with the species dwelling in the litter and in the upper soil layers (in the litter—Dendrobaena octaedra, Dendrodrilus rubidus f. tenuis, and L. castaneus; in the litter-soil layer—L. rubellus; in the upper soil layer—Octolasium lacteum). The higher diversity of the earthworm life forms in the soddy-podzolic soils points to the stronger development of their humus horizons as compared to those horizons in the burozems of the southern taiga and mountains.     

Participation of soil invertebrates in the organic matter decomposition in forest ecosystems of Central Siberia

The biomass of large invertebrates was studied in the soils of forest ecosystems in the forest-tundra and southern taiga of Central Siberia. Its formation is shown to be controlled by the integrated effect of the soil and climatic conditions. The distribution of the zoomass according to the main taxonomic groups testifies to the higher functional significance of the large saprophagous invertebrates in the ecosystems of the southern taiga compared to those of the forest-tundra. The quantitative contribution of the invertebrates-destroyers to the organic matter decomposition was assessed on the basis of field experiments; it was shown to be determined by the quality of the material decomposed irrespective of the conditions and time of its exposition. Every year, soil saprophages decompose 0.5–2.0% of the total phytodetritus reserves in the forest-tundra and 3–14% in the southern taiga amounting to 12–54% of its losses upon decomposition.     

Psychrotolerant actinomycetes of plants and organic horizons in tundra and taiga soils

It has been revealed that in organic horizons and plants of the tundra and taiga ecosystems under low temperatures, actinomycetal complexes form. The population density of psychrotolerant actinomycetes in organic horizons and plants reaches tens and hundreds of thousands CFU/g of substrate or soil, and decreases in the sequence litters > plants > soils > undecomposed plant remains > moss growths. The mycelium length of psychrotolerant actinomycetes reaches 220 m/g of substrate. Application of the FISH method has demonstrated that metabolically active psychrotolerant bacteria of the phylum Actinobacteria constitute 30% of all metabolically active psychrotolerant representatives of the Bacterià domain of the prokaryotic microbial community of soils and plants. Psychrotolerant actinomycetes in tundra and taiga ecosystems possess antimicrobial properties.