Soddy-calcareous Soils Research Articles

Dark-humus soils on the updated soil map of Russian Federation scale 1 : 2.5 M

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.

Formation of the Yield of Flax Seeds of the Oilseed Variety LM 98 during Inoculation with New Strains of Microorganisms of the Rizobakt Biological Product of the RZhF Brand in the Conditions of the Leningrad Region

In 2019 and 2020 on a small experimental field of the Department of Plant Industry named after I.A. Stebut FGBOU VO St. Petersburg State Agrarian University, studies were carried out to study the effect of new strains of microorganisms of Rizobakt biological products of RZhF brand on the growth, development and productivity of oil flax (Linum usitatissimum L.) variety LM 98. The research results showed that in the conditions of the Leningrad region on soddy-calcareous soil and with natural moisture, in order to obtain a stable seed yield at the level of 3.0 t / ha, it is recommended to inoculate oil flax seeds with the preparation Rizobakt of the RZhF brand (strain M) or Rizobakt of the RZhF (strain Sl), which will increase this indicator by 0.4 t/ha or 17%. The studied agrotechnical method stimulates seed germination, increases field germination by 8-30%, adaptation of crops planting to extreme environmental conditions is manifested, increasing the survival rate of plants for harvesting by 10-12%. This contributes to creation of flax stalks with a large (by 22–42%) number of plants per unit area before harvesting. In thickened agrophytocenoses, which are formed under the influence of biological products, in flax plants of the LM 98 variety, 18-19% fewer bolls are formed, seeds–by 15–17% and their weight is less by 10–18%.

ИЗМЕНЕНИЕ ПАВОДКООБРАЗУЮЩИХ СВОЙСТВ ВОДОСБОРОВ НА РЕКАХ СЕВЕРО-ЗАПАДНОГО КАВКАЗА В 2000–2014 гг.

The rivers of the North West Caucasus are characterized by a flood runoff regime. Floods leading to material damage occur on the rivers of the region every year. However, in the XXI century. the development of both automatic monitoring systems and the capabilities of mathematical modeling of hydrological processes make it possible to fill this gap. After the flood of 2012, a network of automatic level gauges is developing in the region, recording water levels every 10 minutes. Analysis of the accumulated archive of observations allows us to determine the features of the formation and passage of floods on the rivers of the region. Among the features of catchments that determine the transformation of precipitation into runoff in the catchment, vegetation and soil cover are distinguished. When it rains in a multi-layer forest, each layer is sequentially moistened from top to bottom. After the vegetation has been moistened, the precipitated water reaches the soil surface and some of it infiltrates into deeper soil horizons up to the waterproof layers, where it replenishes the groundwater lenses. The vegetation cover of the North West Caucasus in the foothill part is represented mainly by plowed steppes with ravine forests, and in the mountainous part – almost entirely by forests. From west to east of the region, mainly oak forests give way to beech and hornbeam forests with a higher water retention. High forest cover and widespread in the region gray, brown forest and soddy-calcareous soils have a water-holding capacity sufficient to absorb intense precipitation. A large proportion of anthropogenic landscapes in the western part of the region causes a lower capacity for absorbing precipitation and, accordingly, a greater flood hazard. Further decrease in forest cover and development of the region will increase the flood hazard.

Correlation of Soddy Calcareous Soils on the Soil Map of the Russian Federation (1 : 2.5 M Scale, 1988) and in the Russian Soil Classification System

Updating of the Soil Map of the Russian Federation (1 : 2.5 M scale, 1988) is planned on the basis of the new classification system of Russian soils. At the first stage, soil information for each polygon on the map is transformed into this system with due account for new factual data. In this paper, we consider problems in reclassification of legend unit “soddy-calcareous soils, including leached and podzolized soils.” In dependence on the geographical position of particular polygons with these soils and the composition and properties of calcareous rocks, the soils of this legend unit are reclassified into different orders, types, and subtypes of the new classification system. The new soil names are introduced into the updated database to the vectorized version of the map. Thus, according to the thickness of the unconsolidated part of the profile, the former soddy-calcareous soils are specified into the orders of lithozems ( 30 cm). Within the latter order, the character of organic and humus horizons is taken into account in identification of the types of dark-humus, gray-humus, mucky–humus, raw-humus, and (probably) light-humus soil types with residual carbonates recorded at the subtype level. The types of raw-humus and light-humus carbolithozems are added to the classification system. An increased content of semidecomposed phytodetritus in the soils is reflected at the subtype level (the subtype of raw-humus soils). This level is also used to reflect the development of eluviation (eluviated soils), illuviation (clay-illuvial soils), and pedogenic transformation of middle-profile horizons (metamorphized, cryometamorphized, ferruginated, and gleyic subtypes) and the inheritance of some specific features of the parent material (red-profile soils). At the species level, the degree of leaching of carbonates from the upper part of the profile is indicated. Plowed soddy-calcareous soils are specified as agrohumus and agro-dark-humus soils. Geographical patterns of manifestation of these soil features and their “soil-ecological” logic are also discussed in the paper.

Restoration of Soils and Vegetation on Reclamation Sites of the Kingisepp Phosphorite Field

Processes of initial soil formation were studied on long-term monitoring plots on dump rocks of quarry no. 3 of the Phosphorite production company in Kingisepp district of Leningrad oblast. Observations were performed in 1998, 2004, and 2014. It was shown that vegetation succession on the plots proceeds relatively quickly, and that the species composition of phytocenoses formed is typical of the areas with soddy-calcareous soils. Soil development proved to be correlated with the development of vegetation. Maximum changes in soil characteristics were observed with an increase in the density of forest vegetation and a decrease in the role of herbs. The molecular composition of humic acids in the studied soils remained stable; in particular, the ratio of aliphatic to alkyl aromatic fragments was virtually constant. This phenomenon could be due to the great amount of aliphatic components in the falloff of coniferous species subjected to humification.

Lanthanides in soils of the Cherepovets steel mill impact zone

Contents of different lanthanide forms in soddy-calcareous soils at different distances from the Cherepovets steel mill (Vologda oblast) have been studied. Increased contents of Pr and Tb are found in soils near the pollution source. Less manifested increases in the contents of other lanthanides (from La to Gd) are also observed. Along with the increase in total content, technogenic pollution increases the content of acid-soluble lanthanides and affects their degree of extraction. The residual fraction strongly bound to aluminosilicates contains 80 to 95% of lanthanides. Soil processes result in the partial binding of lanthanides with organic matter (5–18% of their total content) and Fe and Mn (hydr)oxides (0.1–5% of the total content). The individual properties of lanthanides are clearly manifested in their interaction with these soil components. The highest share of the fraction bound to organic matter contains medium lanthanides, and the highest share of the fraction bound to Fe and Mn (hydr)oxides contains heavy lanthanides.

Contact angles at the water–air interface of hydrocarbon-contaminated soils and clay minerals

Contact angles at the water–air interface have been measured for triturated preparations of clays and soils in order to assess changes in their hydrophobic properties under the effect of oil hydrocarbons. Tasks have been to determine the dynamics of contact angle under soil wetting conditions and to reveal the effect of chemical removal of organic matter from soils on the hydrophilicity of preparations. The potentialities of static and dynamic drop tests for assessing the hydrophilic–hydrophobic properties of soils have been estimated. Clays (kaolinite, gumbrine, and argillite) have been investigated, as well as plow horizons of soils from the Republic of Tatarstan: heavy loamy leached chernozem, medium loamy dark gray forest soil, and light loamy soddy-calcareous soil. The soils have been contaminated with raw oil and kerosene at rates of 0.1–3 wt %. In the uncontaminated and contaminated chernozem, capillary water capacity has been maintained for 250 days. The contact angles have been found to depend on the degree of dispersion of powdered preparation, the main type of clay minerals in the soil, the presence and amount of oxidation-resistant soil organic matter, and the soil–water contact time. Characteristic parameters of mathematical models for drop behavior on triturated preparations have been calculated. Contamination with hydrocarbons has resulted in a reliable increase in the contact angles of soil preparations. The hydrophobization of soil surface in chernozem is more active than in soils poorer in organic matter. The complete restoration of the hydrophilic properties of soils after hydrocarbon contamination is due to the oxidation of easily oxidizable organic matter at the low content of humus, or to wetting during several months in the absence of the mazut fraction.

Biological activity of soddy-calcareous soils and cultural layers in Alanian settlements of the Kislovodsk basin

Microbiological investigations of cultural layers were performed in a settlement of the Alanian culture—Podkumskoe-2 (the 2nd–4th centuries AD). The present-day soddy-calcareous soils (rendzinas) used for different purposes were also studied near this settlement. The most significant changes in the initial characteristics of the soil microbial communities occurred under the residential influence more than 1500 years ago; these changes have been preserved until the present time. In the areas subjected to the anthropogenic impact, the total microbial biomass (the weighted average of 3720 μg C/g soil) was lower than that in the background soil. The minimal values of the microbial biomass were found in the soil of the pasture—2.5 times less than in the background soil. The urease activity of the cultural layer was higher than that of the soils nearby the settlement. Elevated values of the cellulose activity were also recorded only in the cultural layers. The current plowing has led to a significant decrease in the mycelium biomass of the microscopic fungi. In the soil of the fallow, the weighted average value of the fungal hyphae biomass along the profile was twice lower than that in the background soil and cultural layers of the settlement. The pasture first affected the active microbial biomass and, to a lesser extent, the amount of microscopic fungi.

Changes in the structure of soil microbial biomass under fallow

The number and biomass of various groups of microorganisms in fallow soils is greater as compared to plowed soils. The microbial biomass in all fallow and plowed soils is dominated by fungal mycelium (from 90% in the top horizons to 97% in the lower ones). The part of spores in the fungal biomass is higher in plowed soils (from 9% in the top horizons to 4% in the lower ones) as compared to fallow soils (3.5–6%). The fallow soils are characterized by the greater part of prokaryotic microorganisms in the biomass, and the reserves and structure of the microbial biomass are more similar to those in the undisturbed soils. These characteristics changed during a ten-year-long period in a soddy-calcareous soil and during a 25-year-long period in a leached chernozem.

The influence of carbonates in parent rocks on the biological properties of mountain soils of the Northwest Caucasus region

The biological activity of different subtypes of soddy-calcareous soils (rendzinas) of the Northwest Caucasus region was studied. In the Novorossiisk-Abrau-Dyurso region (dry subtropics), typical soddy-calcareous soils with the high content of carbonates predominate; in the more humid conditions of the Lagonaki Plateau (Republic of Adygeya), leached soddy-calcareous soils carbonate-free down to the parent rock are spread. The number of microarthropods, the populations of fungi and bacteria, and the enzyme activity (catalase, dehydrogenase, and invertase) testify that the biological activity of these soils significantly differs. In the typical soddy-calcareous soils of the dry subtropics, the content of carbonates does not affect the characteristics mentioned; in the more humid conditions of the West Caucasus region, the presence of carbonates in the parent rocks intensifies the biological activity of the soddy-calcareous soils.

Biological properties of south Russian soils: Tolerance to oil pollution

Oil pollution of south Russian soils usually leads to reduction in the abundance of ammonifying bacteria, microscopic fungi, and bacteria of the genus Azotobacter, as well as in enzyme (catalase and invertase) and cellulolytic activities. By the criterion of biological tolerance to oil pollution, these soils can be arranged in the following series: ordinary chernozems >= soddy calcareous soils = southern chernozems >= leached chernozems > brown forest soils >= gray sand soils. A regional scheme of ecological safety standards for oil contents in these soil types is proposed.

Chemical contamination of adygea soils and changes in their biological properties

Soil pollution with Cr, Cu, Ni, and Pb oxides and with oil products in the Adygea Republic leads to the deterioration of the soil biological properties. According to the degree of deterioration of the biological properties, the soils of Adygea may be arranged into the following sequence: brown forest soils > mountainous meadow (subalpine) soils > gray forest soils > soddy calcareous soils = leached vertic chernozems. With respect to the negative effect of heavy metal oxides on the biological properties of the soils, they form the following sequence: CrO3 > CuO = PbO ≥ NiO.

Mycological characteristics of the cultural layer of a medieval settlement on soddy calcareous soils

The difference between fungal communities in the cultural layer of a medieval settlement and in the background soddy calcareous soil is shown. In the cultural layer, the portion of spores, especially large spores (d > 6 µ m), in the total fungal biomass is increased, whereas the portion of mycelium, especially with a thick- ness of > 4 µ m, is decreased. The species composition of micromycetes in the cultural layer is also transformed; species from the Aspergillus and Fusarium genera predominate. The frequency and diversity of Penicillium rep- resentatives decreases, whereas the fungal species from the Phoma, Doratomyces, Geomyces , and Verticillium genera, which are not typical of the background soil horizons, increases. The diversity of the minor fungal spe- cies also increases in the cultural layer. An increased content of keratin-decomposing soil fungi is found in the cultural layer. It is argued that the use of the entire set of these characteristics makes it possible to perform mycological indication of the parts of the cultural layer that served different purposes (ancient streets, house floors, backing of the walls, etc.) within the settlement.

SOIL-LANDSCAPE RELATIONSHIPS IN THE TAIGA OF NORTHWESTERN RUSSIA HIGHLIGHT THE DIFFERENCES IN THE U.S. AND RUSSIAN SOIL CLASSIFICATION SYSTEMS

Relatively little work has been published about soils in northwestern Russia, and soil-parent material-vegetation relationships are not well established for this region. Seven pedons developed on late-Pleistocence glacial deposits in the northern, middle, and southern taiga zones of northwestern Russia were described and classified according to the official classification systems of both the United States and Russia. Morphological descriptions and laboratory data that included pH, particle size distribution, selective dissolution analysis, and carbonate equivalent were used for classification. Psamments (Podzols) with Bs and Bhs horizons are most common in the northern taiga, where parent materials are dominated by felsic till and glacial outwash, and vegetation is mostly evergreen conifers. Parent material heterogeneity in the middle taiga promotes soil diversity. Soils on thin calcareous till over limestone are Rendolls (Soddy-calcareous soil); soils on thick calcareous till are Cryalfs (Podzolic soil), and those on slightly calcareous glacial-lacustrine deposits are Psamments (Podzol), with much weaker spodic character than the soils of the northern taiga. Vegetation in the middle taiga varies from broadleaf, deciduous trees on highly calcareous soils, to evergreen conifers on the weakly calcareous soils. The southern taiga region soil formed on calcareous two-layer till is a Cryept (Soddy-podzolic soil) under evergreen conifer forest. Soil properties are clearly linked to the composition of the glacial deposits and to the forest vegetation. We also show that strongly podzolized soils, as indicated by albic horizons and significant subsoil accumulations of carbon and oxalate-extractable Al and Fe, nonetheless fail U.S. taxonomic criteria for spodic material and Spodosols, primarily on the basis of soil color.