Articles

The characteristic of symbiotic relationships is presented on the example of vesicular-arbuscular mycorrhiza in the case of Trifolium pratenseL. at different succession stages of meadow phytocenoses. It is shown that the functional potential of symbiosis changes in the course of succession and is fully revealed under conditions of an undisturbed climax community. The fundamental possibility of biological diagnostics of the state of phytocenosis using discriminant analysis according to the indices of an individual legume plant, taking into account the symbiotic potential, has been demonstrated.

Under the conditions of a model vegetation experiment (30 days), the responses of microbial communities of agro-soddy-podzolic soil of two sites (Chashnikovo, Moscow region) with different organic carbon content (Corg 3,86 and 1,30%) to polymetallic pollution with heavy metals (HM: Cu 660, Zn 1100, Pb 650 mg/kg) and treatment with biochar (5%) and lignohumate (0,25%) Methods of classical inoculation on Czapek agar and analysis of soil lipid profiles by gas chromatography—mass spectrometry, an assessment of the differences in abundance colony forming units (CFU), the biomass of fungi and bacteria, the diversity of cultivated fungi in humus-rich and humus-poor soil. HMs did not have a significant effect on the number of CFU and the number of cultural-morphological types of colonies, but they reduced the biomass of fungi and bacteria in both soils, while this decrease was much more pronounced in a weakly humus soil. In addition, the differences between the soils manifested themselves in a different increase in the proportion of resistant melanized forms of fungi under the influence of HM in a highly humified soil — by 25,9%, and in a weakly humified soil — by 45,7%. The sensitivity and universal significance of structural indicators as indicators of the stability of microbial complexes under chemical contamination of soils of different humus content are discussed; among the studied, the most sensitive and reliable indicators include the assessment of the proportion of melanized fungi.

The characteristic of typical and humus petrozems of the most high-altitude belt zone of the Khibiny, formed under three predominant types of plant groups corresponding to different stages of primary succession, is presented. For these soils, there is no differentiation of the profile by the content of most elements, with the exception of phosphorus, which is concentrated in the surface organogenic horizons. According to many chemical and phy sicalchemical properties, the soils of the char belt are close to Entic Folic Podzols formed in the underlying mountain-tundra belt under shrubby vegetation. The biological activity of petrozems below or is comparable with this parameter in the soil of shrub tundra. It was found that as the structure of vegetation becomes more complex, the activity of microorganisms increases and the organic matter of the soil stabilizes. Overall, the microbial community of petrozems well adapted to extreme conditions.

Indicators of cadastral value of soils in agroclimatic subzones of agrolandscapes of the Irkutsk region are determined. The sensitivity of cadastral value calculation approaches to various soil and geographical conditions is shown. Low values of the cadastral value of agricultural land are due to low values of agroclimatic potential.

The article is devoted to the assessment of the influence of biotic, abiotic and anthropogenic factors on the dynamics of production processes of various ecosystems located in one natural and climatic subzone — the southern taiga of the Eastern European Plain.

The study was carried out on the example of four key sites in the Vladimir region, located in different landscape provinces in similar climatic conditions, but with certain differences associated with the characteristics of the soil and vegetation cover, anthropogenic load, and land use structure. Calculation of productivity indicators in carbon units is based on MODIS GPP/NPP data. The amount of organic carbon in the soil is determined according to the UN Food Organization (FAO) based on the Trends.Earth module of the GIS QGIS package.

Common to the four ecosystems is the course of changes in the indicators of vegetation productivity over the years against the background of its different absolute values. Favorable conditions for the accumulation of carbon in the soil are formed in areas with high productivity and a large number of overgrown lands. The results of analysis of variance ANOVA demonstrate that the factors of time and spatial position of key sites do not affect the content of soil organic carbon and gross biological productivity. Land use structure is a significant factor. It is shown that the insufficient productivity of some ecosystems is compensated by an increase in the productivity of neighboring ones, therefore, the preservation of intra-landscape diversity is a necessary condition for maintaining the stability of their functioning.

The composition of water extracts of soils developing within the het erolithic geochemical landscape of the Klyazma river basin in its upper reaches has been studied. The main factor that determines the content of water-soluble components is the genesis of soils and the position of the soil in a series of elementary landscapes. The specifics of the content of water soluble macro- and microelements in the soil profile outside the zone of anthropogenic influence and developing according to the eluvial- illuvial type is due to their natural organization, with the combination of podzolization in combination with texture organization. Under the con ditions of a supersquale landscape that has emerged from the flood regime, characterized by the complexity of the soil cover, the distribution of water soluble components in the soil profile is determined by the carbonate content and proximity to the surface of soil ground water. An additional factor determining the composition of soil water on the lowered elements of the relief is the underlying soil with peat bogs. It is shown that calcium is among the most important elements that determine the specificity of the studied heterolithic landscape. The composition of water-soluble components for each of the soils is specific, which is confirmed on the basis of the results of cluster analysis.

This article provides an analysis of structural and functional indicators of bacterial complexes taken for examination from the complete profile of the fens that form part of “Klukvennoye” and “Karbyshevskoye” wetland systems in the Tomsk Region. In the fens bacteria was found throughout all the profile. The number of bacteria was high and varied from 27 to 78 ´ 10⁹ cells/g of dry peat. This data was obtained by direct method using fluorescence microscopy. The high count of the saprotrophic bacteria (reaching up to 10⁸-10⁹ CFU/g of dry peat) was found by the plate method. Those results allowed to identify a trend, showing that the number of saprotrophic bacteria increased down the fen profile.  The results of this study give an opportunity to state for the first time that the index k ( k is a dimensionless universal characteristic of natural prokaryotic communities, k stands for microscopy/plate) in fen profiles does not increase, but decreases with depth. The following bacterial cultures were identified and isolated from the fens studied (those cultures were attributed to 10 taxa): Bacillus, Streptomyces, Arthrobacter, Microbacterium, Pseudomonas, Pedobacter, Flavobacterium, Dyadobacter, Janthinobacterium, Myxobacteriales. Bacterial cultures, representing Bacillus and Streptomyces genera, were dominant in the acrotelm. At the same time Pseudo-monas, Dyadobacter and Arthrobacter dominated in the catotelm. The functions of bacterial genera and species, identified by molecular biological methods, were described. A study of nitogen fixation, nitrogen decline and methanogenesis showed that bacteria were in a viable state and were able to remain active throughout the entire peat profile.

The features of the modern radioecological situation in forest (pine, spruce, birch) and fallow ecosystems in the contaminated (southern part) and background (northern part) territories of the Kaluga region are analyzed in this article. The density of soil contamination of the studied region by natural radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K) corresponds to background levels, while technogenic radionuclide (¹³⁷Cs) significantly exceeds the background value (3 kBq/m²) and ranges from 60,8 to 273,8 kBq/m². Forest ecosystems (especially coniferous) are the most contaminated by ¹³⁷Cs, and fallow ones are the least contaminated. The density of ¹³⁷Cs soil contamination has decreased on average by more than 3 times compared to the initial period after fallouts (1986), but still significantly exceeds the permissible level (37 kBq/m²). The main contribution to the total specific activity of soils, as well as the power of the equivalent absorbed dose, is made by ¹³⁷Cs in the ecosystems of the contaminated areas, and by ⁴⁰K - in the ecosystems of background areas.

Soil is the basis of food systems at all levels. Preservation of the ecological functions of the soil cover, its condition in the territories newly introduced or withdrawn from agricultural use determines the degree and time of the onset of environmental risks, as well as risks and threats to food security.

The global value and cost of soil resources is increasing. Russia has a maximum soil cover of approximately 14,5 million km2—one sixth of the planetary. Soils, which are a unique national wealth and strategic resource, are underestimated. The volumes of applied agrochemicals are insufficient for the reproduction of fertility.

The achievement of food security indicators in the country and the export of food pro ducts occur due to non-reimbursable expenses of soil fertility reserves. There are no state documents that would clearly and unequivocally determine how many arable soils and agricultural land are needed to conduct modern agricultural production and fulfill tasks for sustain able development goals.

The composition of bottom sediment in the estuarine part of the Simmi River, a small tributary of the Amur River (Bolon State Nature Reserve, Russian Far East), was studied using X-ray fluorescence, electron microscopy, sedimentation analysis, and laser diffractometry. It is established that the formation of labile components in the bottom sediments (vivianite–clay microaggregates, gypsum microcrystals, and vaterite mesocrystals) is linked with effects of the pyrogenous factor in the Simmi River basin and the level regime of the main river. The formations are mobile due to their small size (<100 μm). The bottom deposits are primarily formed by such suspended sediments (particle size <100 μm), which is consistent with the lacustrine–alluvial genesis of the area. Two vivianite formation mechanisms have been identified in the bottom sediments in periods following fires, when the concentration of phosphate ions in the river water is elevated. Vivianite is formed on the surface of ferruginous–clay microaggregates, due to the reduction of Fe (III) in the presence of organic matter and on biological templates (organic residues and single-celled microorganisms).