Articles

The distribution patterns of microelements in soils along two soil-geochemical catenas within the "Chashnikovo" territory in Moscow Oblast were studied. The first catena, "Klyazma", is associated with the northeastern slope of the Klyazma River valley and includes eluvial, transit, transit-accumulative, and superaquatic landscapes. Within this catena, a carbonate double-sided biogeochemical barrier was diagnosed at the contact zone between the transit and transit-accumulative landscapes. A distinctive feature of this catena is the modern functioning of the superaquatic landscape in its post-hydromorphic stage of development. The type of this catena is heterolithic due to the transition from cover loams on moraine to alluvial deposits within its boundaries. The second catena, "Kirpichnoye Pole", consists of eluvial and a series of transit-accumulative landscapes with varying hydromorphism degrees. The eluvial landscape is located in the well-drained upper part slope of northeastern exposure. The second site within the transit-accumulative landscape is situated in the contact zone of the partially drained lower part of the slope, influenced by the gully "Krasnyy Voyn". The third and fourth sites of this landscape are characterized by increasing levels of hydromorphism. Throughout the entire length of the catena, soil formation occurs on cover loams underlain by moraine, which allows it to be classified as monolithic. The relevance of the study is determined by the fact that the typological differences between the catenas and the presence of a carbonate biogeochemical barrier in one of them allowed us to establish similarities and differences in element behavior under different conditions. Element behavior reflects general features common to soils within the southern taiga landscapes of Moscow Oblast. The distribution pattern of elements in soils is explained by soil-forming processes, past agricultural activities, bioaccumulation processes, and the influx of elements as pollutants due to the proximity of these landscapes to the M-10 highway ("Moscow-Saint Petersburg") and residential buildings. Texture-differentiated soils show correlations between silt fraction content and elements such as V, Cr, Fe, Ni, Cu, and As, while alluvial soils exhibit strong links between medium silt fraction and Mn, Fe, As, Mo, Cd and Hg. Within the studied catenas, the increase in hydromorphism leads to the accumulation of iron-manganese concretions in the soils. The carbonate barrier reduces the overall migration flow primarily of elements belonging to the iron family.

Some historical data on the study of the soil and vegetation cover of the Chashnikovsky extension of the Klyazma River are presented, as well as the results of the study of parent rocks, soils, snow cover composition and distribution of elements in the territory of the superaquatic landscape of the MSU TESEC, including the floodplain soils of the Klyazma River. The parent rocks for this territory are alluvial deposits (14.5% of the total area), peat underlain by deluvial deposits (13.2%), peat underlain by alluvial deposits (12.9%), and alluvial deposits underlain by peat (8.4%). Nine subtypes of alluvial soils have been identified, belonging to 5 types. Alluvial meadow-bog soils predominate (35.8% of the floodplain territory); alluvial meadow acidic soils (21.2%), alluvial bog silt-peat soils (18.9%), alluvial soddy acidic soils (15.5%), and alluvial bog silt-humus-gley soils (8.6%) are also distinguished. The distribution pattern and chemical composition of the snow cover of the EE SEC "Chashnikovo" superaquatic landscape were studied based on 9 selected sampling points. The average height of the snow cover in the floodplain area is 37.8 cm, the snow cover reserves are 118.8 kg m–2 with an average snow density of 0.32 g cm–3. The snow within the superaquatic landscape of the EE SEC "Chashnikovo" is characterized by a low content of components and belongs to the bicarbonate-calcium-sodium-magnesium class. The superaquatic landscape zone is characterized by low values of the content of the main components in the snow water, since it is located far from the M-10 "Moscow - St. Petersburg" highway and populated areas. In the terrace part of the floodplain, relatively high levels of calcium, magnesium and potassium are found in soil solutions. The soils of the central floodplain depressions are characterized by a significant increase in the content of sodium and iron, chloride ion, and among microelements - chromium, copper, zinc and strontium. For the soil of the elevated part of the central floodplain, which has already entered the automorphic stage of development, a decrease in the content of most cations and anions was found. The predominant elements in the composition of new formations in floodplain soils are iron and manganese. Among heavy metals, lead ranks first in terms of accumulation.

The features of the morphological organization of sod-podzolic soils are considered using the example of age-diverse deposits operating in various ecological and genetic conditions. Separate phases of transformation of the soil material of the former arable horizon are identified, associated with the stages of overgrowth of fallow lands. Attention is paid to the resistance of sod-podzolic soils, on the one hand, to agropedoturbation, and, on the other, to the action of zonal factors of soil formation in the postagrogenic period, depending on the degree of soil cultivation in the previous time. It is shown that by the age of 20‒30, the upper part of the profile shows traces of the effects of gilding and eluvial-gley processes, which are reflected in the specific features of the structure of the soil stratum — the appearance of interlayers and spots of podzolized material with characteristic horizontal layering, the appearance of humus nodules, ferruginous-manganese compounds and lightening of the entire material of the former arable horizon.

The article summarizes and presents the results of long-term studies on the effect of mineral, organic fertilizers and liming on crop productivity depending on the degree of cultivation of sod-podzolic soil. It is shown that fertilizers act as a powerful factor capable of increasing the yield of agricultural crops and improving their quality, that the yield of field crops is directly dependent on the degree of cultivation and fertility of the soil. It is shown that in sod-podzolic soil of varying degrees of cultivation, complete or partial replacement of urea with MFU in the composition of triple (NPK) mineral fertilizer does not solve the problem of increasing the efficiency of nitrogen fertilizers. When studying the productivity of grain crops (winter wheat, winter rye, spring wheat, oats, barley), it was found that regardless of the form of nitrogen fertilizers, the optimal dose of NPK for all the above crops did not exceed 100–150 kgha-1 of the active substance of each element. This dose made it possible to realize the potential of the studied varieties of grain crops by 60–80%. The efficiency of nitrogen doses over 100 kgha-1, both when using urea and its combinations with MFU, leads to deterioration of the enzymatic activity of soils. The level of cultivation of sod-podzolic soil remains decisive in the formation of agricultural crop yields and with intensive use of fertilizers.

A detailed morphological study of bog-podzolic superficial-gleyed soils (sod-humus and peaty subtypes) and living ground cover within the soil-geochemical catena in Moscow region Solnechnogorsk district was conducted. For the first time, more than 20 morphological indicators of soils within the organogenic, eluvial and eluvial-illuvial parts of the profile were determined and analyzed over a thirty-year period. At the same time, the characteristics of the associated living ground cover (biomass, proportion of hygrophytes, moisture and trophicity scores according to L.G. Ramensky) were studied. Based on monitored indicators analysis, it was shown that convincing and reliable identification of the degree of bogging of a biogeocenosis is possible without additional analytical studies of soils and plants. Mathematical analysis of field research results indicates statistically significant relationships between the degree of swamping and such indicators as the proportion of hygrophytes, moisture score, litter thickness, the ratio of subhorizon reserves F/L, the thickness of the eluvial horizon, the depth of gleying from the lower boundary of the organogenic layer, and the abundance and size of nodules. It is likely that in the landscape, the soil serves as an “archive” of hydromorphism conditions of varying degrees, while the living ground cover can serve as a sign of swamping only at significantly pronounced process stages. The greatest contribution to the hydromorphism of the studied bog-podzolic surface-gleyed soils is made by: the groundwater level, the upper boundary of the appearance of signs of gleying from the lower boundary of the organogenic horizon, the general abundance of spots in the eluvial horizon, the average size of nodules in the eluvial-illuvial horizon.

The carbon reserves in main components of Moscow region coniferous-broadleaf forest were studied: various fractions of the tree stand, dead wood, mortmass, litter, living ground cover and mineral profile of the soil. To assess the potential intensity of organic matter decomposition, a number of indicators of the functioning of the microbial biomass were determined. An assessment is given of the carbon reserves and their shares in the ecosystem components that differ in the rate of renewal and potential capacity for carbon sequestration, as well as the degree of their spatial variation. The total carbon pool of the studied forest ecosystem is 18.7+0.8 kg·m–2, with almost 90% of the total stock concentrated in the perennial parts of the tree stand, dead wood, mortmass and mineral profile of the soil. These most stable pools are characterized by the least spatial variation within the biogeocenosis. The carbon reserves of the assimilating part of the grass layer and tree leaves are only 0.02 and 0.08 kg·m–2, respectively. The carbon reserves of litter are quite low - 0.21 ± 0.04 kg·m–2, which does not exceed 2% of the total carbon reserves of the ecosystem. The data obtained indicate that even secondary subclimax forest ecosystems are a significant absorber of atmospheric carbon, mainly due to the mass of the tree stand and soil organic matter.

The ongoing work on forecasting changes in soil carbon reserves using various mathematical models requires primary data for different points in time. The paper examines archival results of observations of intra-seasonal carbon dynamics obtained in 1983 on arable sod-podzolic soils in Educational and Experimental Soil and Ecological Center of Lomonosov Moscow State University "Chashnikovo". Measurements were carried out from June to September on 30×30 m plots located in three crop rotation fields. Samples were taken from layers 0‒10 and 10‒20 of the arable horizon. The number of measurements in each period on each field was 25. After preliminary rejection of the results that did not meet the hypothesis of homogeneity of the soil horizon, the data were processed by ANOVA. It is shown that in the arable horizon (0–20 cm layer) the range of intra-seasonal variability of carbon content can be about 0.10%. Minimum values of carbon content were observed in August-September.

The methane uptake and the carbon dioxide emission by Albic Retisols (Aric) under the cultivation of green manure crops and perennial grasses, as well as the carbon accumulation in their phytomass were estimated at the «Chashnikovo» carbon supersite of the Moscow region during the summer period of 2024. White mustard, vetch-oat mixture, perennial legume-cereal grasses and giant miscanthus were studied. Greenhouse gas fluxes were measured using an automatic chamber, aboveground phytomass assessed by the mowing method, underground phytomass — by washing roots from soil monoliths. The soils absorbed atmospheric methane at the rate of 0.15 to 0.62 mg C·m‒2·day‒1. The highest total methane uptake over the summer was observed in soils under miscanthus at the rate of –0.047 g C·m‒2, it statistically significantly decreased by 1.6 times in soils under the vetch-oat mixture, by 1.8 times under perennial grasses and by 2.2 times under mustard. The total CO2 emission by soils over the summer was maximum under perennial grasses — 927.6 g C·m-2, decreased under miscanthus – 835.9 g C·m‒2, vetch-oat mixture — 737.4 g C·m‒2 and mustard — 476.6 g C·m‒2. The increased CO2 emission by soils under perennial crops is due to more active root respiration during the formation of statistically significantly greater underground phytomass compared to green manure crops.  The aboveground phytomass of giant miscanthus was more than 2 times higher compared to other plants. In total, over the growing season, the following carbon accumulation was observed in the phytomass: 536.0 g C·m‒2 in white mustard, 735.9‒755.3 g C·m‒2 in legume-cereal perennial grasses and vetch-oat mixture, 2157.7 g C·m‒2 in miscanthus. Thus, the studied Albic Retisols (Aric) acted as a weak sink of atmospheric methane and emitted carbon dioxide in an amount less than or comparable to the carbon accumulation in the phytomass of green manure crops and perennial grasses. These data are important for the development of technologies aimed at reducing greenhouse gas emissions and increasing carbon sequestration in agroecosystems.

The effect of polymer soil amendments on changes in toxicity of agro-sod-podzolic soil spiked with a complex of heavy metals (HM) has been characterized. Hydrolyzed polyacrylonitrile (HYPAN) and a binary composition of HYPAN+potassium humate (HYPAN+PH, 1:10) were applied at a rate of 0.2% (on a dry matter basis) to soils with model contamination by Cu, Zn, Pb, and Cd at levels of 2, 4, and 6 approximate permissible concentrations (APC). Samples without ameliorant treatment served as a control for all soil pollution levels. The effect of polymer formulations on reducing the toxicity of heavy metals manifested to varying degrees depending on the level of soil contamination. The bacterial standard bioluminescent biotest and phytotesting on the seedlings of higher plants Sinapis alba L. showed a positive effect of the HYPAN+PH composition at the highest contamination level, 6 APC. Bioindication of the functional state of soil microbiota showed that ameliorants lowered the microbial metabolic coefficient (to an acceptable level of 2 µg C-CO₂ mg⁻¹·Cmic·h⁻¹), which is important evidence of their positive effect on the soil microbial community. Laboratory biotesting of uncontaminated soil, as well as at relatively low levels of HM contamination, revealed the toxicity of the aqueous extract of samples with ameliorants (inhibiting root growth and quenching bioluminescence in bacterial bioassay). In light of the findings of this study, it is recommended that further analyses should be conducted before suggesting the use of tested ameliorants for the detoxification of polluted soils.