The influence of fires on the properties of forest soils in the Amur River basin (the Norskii Reserve)

The influence of forest fires on the properties of taiga brown, gley taiga brown, and alluvial bog soils widespread in the area of the Norskii Reserve (the Amur River basin) was studied. During several years after the fire, the humus content increased, especially in the soils subjected to fires of high intensity. In the soils of steep slopes, the humus content decreased due to damage to the forest vegetation and activation of lateral runoff after the fire. As a rule, in the soils subjected to fire, the C ha-to-C fa ratio increased and correlated with the fire intensity. Some relationships between the forest fires and the acid-base properties of the soils were revealed. After the fires, the pH values often became higher. The stronger the fire, the higher the pH values. The stony soils differed from the other ones, since the reaction of their upper horizons turned out to be more acid after the fires. The analysis of the authors’ and literature data showed that the pyrogenic changes of some soil properties have been poorly studied and need further investigation, including their geographical aspects.     

Effect of the Geological Factor on Polyarenes in Soils

The study, generalization, and comparative analysis of data on the content and composition of polyarenes have been performed for the soils subjected to the impact of the following factors: (1) approach of bituminous material to the surface along the fault zone from the deep layers of sedimentary rocks with the formation of bituminous sandstones and asphalt lenses (Bakhilovo asphalt deposit, Zhiguli dislocations, Samara region); (2) periodical discharge of large amounts of volcanic tephra into the atmosphere resulting in the formation of pyroclastic deposits (near the Avacha Volcano, Kamchatka region); (3) increased geodynamic activity within the area of the recent blocky structure of the earth crust, where a spontaneous upward flux of fluids into the soil is possible (Istra morphostructural node, Moscow region); and (4) high fumarolic activity resulting in the impact of hot water and vapor on the surrounding soils (Golovnin caldera, Island Kunashir, Kuril region). It has been found that the considered manifestations of geological factors can be arranged into the following increasing order: (a) exposure of volcanic tephra as a parent rock (20 ng/g); (b) increased hydrodynamic and fumarolic activity (85–90 ng/g); and (c) penetration of asphalt into the sedimentary rocks (4800 hg/g). According to the diversity of polyarenes identified in the soils, the considered situations form the following increasing series: (a) 9 out of 11 identified polycyclic aromatic hydrocarbons (PAHs) are found in the area of increased geodynamic activity and in the region of volcanic tephra fallouts; (b) 10 PAHs are identified in the asphalt deposit; and (c) all 11 PAHs are identified in the area of fumarolic activity.     

Polycyclic aromatic hydrocarbons in pyrogenic soils of swampy landscapes of the Meshchera lowland

The composition and distribution of polycyclic aromatic hydrocarbons (PAHs) were studied in organomineral and organic soils of the Meshchera National Park. It was found that the background oligotrophic peat soils unaffected by fires in central parts of the bogs are characterized by the increased PAH concentrations due to their high sorption capacity. The fires of 2007 and 2010 resulted in the transformation of the plant cover and soil morphology, the formation of new horizons, and the change in the PAHs content and composition. Significant burn-off of organic matter was found in oligotrophic-eutrophic soils and resulted in the decrease of PAHs content after fire. Only partial burn-off of organic horizons and intense formation of PAHs were recorded in the soil with initially great thickness of peat horizons. Pyrogenic accumulation of PAHs was identified in organomineral soils of the marginal parts of bogs and of forest sites.     

Soils of sinkholes on the western macroslope of the southern Urals: Properties, catenary relationships, and regional specificity

A series of microcatenas on the slopes of sinkholes were studied on the western macroslope of the southern Urals in the Shulgan-Tash Reserve. The morphological, chemical, physical, and physicochemical characteristics of the soils were analyzed. In order to reveal their regional specificity, the soils of the sinkholes under broadleaved forests in the southern Urals were compared with analogous soils under the northern taiga of the Belomorsk-Kuloi Plateau. It was shown that the full-profile vertically differentiated soils in the upper parts of the microcatenas are replaced by weakly developed and slightly differentiated soils in the lower parts of the microcatenas crossing sinkholes of different diameters in both natural zones.     

Hydrocarbon contamination of arctic tundra soils of the Bol’shoi Lyakhovskii Island (the Novosibirskie Islands)

Data on the distribution of the components of oil products that have accumulated in the arctic tundra soils of the Bol’shoi Lyakhovskii Island (the Novosibirskie Islands) under the impact of technogenic loads are analyzed. The examined soils differ in the vertical and lateral distribution patterns of the methanenaphthenic and naphthenic hydrocarbons and in the degree of their transformation. This is determined by the position of particular soils in the catenas and by the sorption of particular hydrocarbon compounds in the soils. The portion of light molecular-weight hydrocarbons in the upper horizons decreases by two-ten times in comparison with the deeper soil layers. In the lateral direction, the twofold difference in the contents of the methane-naphthenic and naphthenic hydrocarbons in the upper horizons is seen. The degree of transformation of the hydrocarbons under the impact of microbiological processes depends on the aeration conditions, the depth of permafrost table, the composition of oil products, and the soil organic matter content.     

Soils of karst sinkholes in the southeast of the Belomorsk-Kuloi Plateau

A series of soil-geochemical microcatenas on the slopes of karst sinkholes in the southeast of the Belomorsk-Kuloi Plateau have been studied. Several types of karst sinkholes have been specified according to the character of surface deposits overlying karstic rocks. The morphological characteristics of the soils of these microcatenas and their chemical and physicochemical properties have been analyzed. On the slopes of the sinkholes, various variants of iron-illuvial podzols and texturally differentiated soils with superimposed profiles of podzols in their upper coarse-textured parts are developed. It is shown that the combinations of the particular factors of soil formation in karst landscapes can both reduce and enhance the vertical differentiation of the soil profiles forming in the sinkholes of different types, which is manifested in the properties of these soils and in the specific of their catenary variations by the elements of the karst topography.     

Lateral migration of soil solid-phase material within a landscape-geochemical arena detected using the magnetic tracer method

Thorough studies of the lateral migration of the solid soil material and the large-scale mapping of the soil cover have been performed within a landscape-geochemical arena in the small catchment area of the Lokna River basin (Tula oblast). Podzolized clay-illuvial agrochernozems are the predominant soils in the catchment area. Nine soil types from four orders according to the 2004 soil classification have also been described. The morphological analysis of the soil profile structures revealed their changes related to the lateral migration of the solid-phase products of the pedogenesis. From the estimated reserves of the spherical magnetic particles as tracers of the mass transfer, the accumulation and dispersion zones of the solid-phase material in the soil cover have been separated and conclusions about the genesis of these zones and their place in the migration structure of the catchment basin have been drawn. The soil catenas within the landscape-geochemical arena have been classified in accordance with the migration intensity of the soil solid-phase material, the localization of deposits, and the degree of openness of the soil-geochemical conjugations. The effect of the lateral migration of the soil solid-phase material on the structure of the microarena soil cover and the soil genetic profiles has been revealed.     

Polycyclic Aromatic Hydrocarbons and Carbon Isotopes in a Palsa Peat (Bol’shezemel’skaya Tundra)

Eurasian Soil Science - The content of polycyclic aromatic hydrocarbons (PAHs) and carbon isotope composition in the peat of a palsa near Eletsky settlement, Vorkuta urban district, Komi Republic...     

Soil erosion under different land uses: Assessment by the magnetic tracer method

A new method of magnetic tracer was applied by the authors for a quantitative assessment of erosional processes. The rates of erosion were determined for cultivated and virgin soils (predominantly, chernozems) on slopes in different parts of the United States and Russia. Quantitative parameters of soil loss and soil deposition for the slopes of different shapes and aspects were found. Specific features of erosional processes within different parts of slopes were revealed. The relationships between the intensity of erosion and the humus state of the soils were characterized, and the effect of land use on the rates of soil erosion was estimated.