Počvovedenie

Comparative study of the magnetic susceptibility of two subtypes of Siberian chernozems was carried out, depending on the characteristics of their geographical distribution, the formation of properties and composition. A total of 12 soil sections of these soils were studied, nine of which are represented by ordinary chernozems, and three by leached long-term frozen and permafrost chernozems of Western, Middle and Eastern Siberia. The volumetric magnetic susceptibility (χ) of the studied chernozems was determined using a specially developed and patented, accurate, express and reliable method using a small-sized KM-7 cappameter from the Czech manufacturer StatisGeo. Specific magnetic susceptibility (χ) was calculated using the formula: χ = χ/р, where р is soil density, kg/m³. It is shown that the studied chernozems of Siberia are formed in contrasting landscape-climatic conditions of soil formation and lithogenic composition of soil-forming rocks, which leads to significant differences in their magnetic susceptibility, manifested both at the subtype level and at the level of individual pedons. Close positive correlations have been established between the specific magnetic susceptibility of these chernozems and the content of humus, coarse and medium fractions, as well as fine sand, negative ones for pHн₂o, the amount of easily soluble salts and CaCO₃. If the ordinary freezing chernozems of the European territory of Russia are characterized by a typically accumulative type of magnetic profile, then the long-freezing and permafrost soils of Siberia are characterized by a regressive-accumulative type. At the same time, ordinary frozen chernozems differ from long-term frozen soils by large statistically significant values of specific magnetic susceptibility, which, in our opinion, is associated with the processes of cryogenic ferruginization.

A comparative assessment of pH, concentrations and fluxes of dissolved organic carbon and total nitrogen was carried out in three types of biogeocenoses: poaceae birch forest, tall herbs alder-willow birch forest and a forb-poaceae meadow. The plots are located on an abandoned arable land in the Cherepovets district of the Vologda Oblast; the soil type is sod-podzolic postagrogenic residual-calcareous. The influx of dissolved organic carbon in forest biogeocenoses is 4.2 times greater than in meadow biogeocenoses; the deflux in forest ecosystems is 3.6 times lower compared to meadow. The influx of dissolved total nitrogen does not differ in the studied biogeocenoses, while the deflux in meadow biogeocenoses is 5.4 times greater compared to forest ones. Carbon accumulation in the soil profile of forest biogeocenoses averages 48.5 kg C/(ha year), while for meadow biogeocenoses the balance between the influx with atmospheric deposition and the deflux with soil water is close to neutral (–1.7 kg C/(ha year)). Nitrogen accumulation rate in forest ecosystems is 1.5–1.7 kg N/(ha year), but only 1.0 kg N/(ha year) in the meadow biogeocenoses. It has been shown that the formation of woody vegetation on abandoned arable land has a significant effect on the fluxes of dissolved organic carbon and nitrogen, both during the passing of organic matter through the tree canopy and the soil profile.

The qualitative and quantitative characteristics of micromycete communities in soils along a toposequence from a floodplain to the summit of a carbonate plateau in the mountain landscape of the Polar Urals were investigated. The biomass of fungi in the studied soils varies within the limits of 0.13±0.01 – 1.63±0.81 mg/g. The main contribution to its structure is made by fungal spores (up to 100% of the total biomass). The length of mycelium of microscopic fungi in upper organogenic horizons of soils varies from 18.45±8.70 to 162.71±134.89 m/g. The total taxonomic list of cultured micromycetes includes 38 fungal species from 19 genera, two divisions and sterile mycelium. The smallest number of species (12) was recorded in the soil under the herb-grass-sedge-moss community in the lower part of the slope, and the largest number of species (18 species each) was recorded in the soils of the floodplain herb-grass-grass meadow and spotted dryad tundra. The Mucoromycota Division is represented by 10 species from the genera Linnemannia, Mortierella, Mucor and Umbelopsis. Fungi of the Ascomycota division predominate in mycocenoses of the studied soils on carbonate rocks. The genus Trichoderma (8 species) is the leader by the number of species. The genus Penicillium has low species diversity in conditions of weakly acidic and weakly alkaline reaction of the environment. It has been shown that the fungal complexes of soils developed on carbonate rocks are characterized by low abundance, poor species and genus diversity, and the dominance of sterile mycelium. In tundra conditions, the quantitative characteristics of mycocenoses in carbonate-containing soils depend on the composition and structure of the plant community as well as the organic matter content in the soils. The CaCO₃ content does not determine the total abundance and biomass of fungi in soils, but it may influence the taxonomic structure of micromycetes through an increase in pH.

Since the birth of civilizations, human activity has led to such degradation processes as erosion, pollution, desertification and others. However, soil changes as a result of military operations, even in localized areas, can lead to the complete withdrawal of these lands from economic turnover. Despite the fact that the total area of the territory affected by military operations is only 0.024% (121 406 km²) of the total area of the Earth, the damage to the soil cover is catastrophic. The aim of the paper is to analyze the literature sources on the study of physical and chemical changes in soils as a result of military activities. The search covered the period from 1950 to 2024 for all known military conflicts of the world. After analyzing the works, the changes were categorized into physical, morphological and chemical. Physical manifested as soil compaction from tracked machinery. Changes in morphological properties are manifested in the form of removal of soil horizons as a result of construction of defensive structures, mixing of soils. The greatest damage occurred as a result of explosions of shells and bombs. In the first months of World War I alone, more than 20 million craters were formed throughout the theater of war. In localized battles, such as the Battle of Stalingrad, more than 40 thousand craters and craters were counted on an area of less than 500 km². Description of the processes of mixing and movement of solid-phase material allowed to reveal a new form of pedoturbation – bomboturbation. As a result of explosions of shells and bombs, soils of craters have O-A-(B)-C profile. With the development of military science to physical and morphological disturbances were added chemical pollution of soils by fuel, heavy metals, as well as input of nitroaromatic explosives, organophosphorus nerve agents, radioactive elements, dioxins from herbicides. For decades, soils in war zones as well as military ranges have been heavily contaminated with toxic compounds, mainly explosives and munitions (and their residues) containing harmful substances including antimony (Sb), lead (Pb), uranium (U), 2, 4- dinitrotoluene (DNT), 2, 4, 6-trinitrotoluene (TNT). These compounds are resistant to biological degradation or recycling and become a source of pollution potentially hazardous to human health and the environment. The extent of chemical contamination of soils as a result of warfare is enormous. Thus, only as a result of the war in Vietnam 14% of the country’s territory was polluted with defoliants and herbicides. The accumulated experimental and theoretical knowledge on the impact of military actions will allow tracing the transformation of various soil properties.