1.5.19. Почвоведение

Research was conducted to assess the mineral nitrogen content and urease activity in ordinary carbonate chernozem soil (Haplic Chernozem) following the application of humic fertilizers. The humic fertilizers used were potassium humate from peat and leonardite activated by a microbiological preparation. The experiment was conducted in 2023–2024 at the Rostov Agrarian Research Center in the Azov zone of the Rostov Region. The study covered two growing seasons with contrasting weather conditions: one with excess moisture at the beginning of the season and subsequent precipitation deficit (2023) and an extremely dry and hot season (2024). This allowed for an assessment of the effects of humic substances on the nitrogen regime of chernozem soil under varying hydrothermal stresses. It was established that the effect of humic fertilizers on the nitrogen regime is indirect and largely determined by the weather conditions of the year, primarily the moisture regime. Under favorable or moderately stressful conditions, they act as activators of biological processes, increasing the efficiency of soil resource and mineral fertilizer use. Under extreme drought conditions, their role shifts toward maintaining soil fertility and the stability of the agroecosystem by improving the soil's physicochemical properties. This makes the use of humic fertilizers, and particularly those based on leonardite, strategically important.

Flood irrigation used in rice cultivation represents a large-scale and rather aggressive intervention in soil hydrology, chemistry, and ecology; therefore, assessing its consequences remains highly relevant. Dark chestnut soil under rice crop rotation was studied in 2002 and again in 2023, twenty years after irrigation had ceased. Noticeable changes were recorded already during field observations. Morphologically, they included a pronounced upward shift of the depth of effervescence with 10% HCl (from 40 cm to the surface), an upward shift of the horizon with carbonate accumulations (beloglazka) (from 117 cm to 32 cm), the occurrence of fine gypsum crystals throughout the soil profile, and the development—below 110 cm—of a gypsum accumulation horizon composed of large crystals and drusy aggregates, including swallowtail (twinned) forms.

The article presents the results of a study and calculation of soil organic carbon stocks in sealed areas of the cities of Rostov-on-Don, Aksay, and Bataysk. Special attention is given to the justification of the soil layer thickness that should be considered when calculating soil organic carbon stocks. Based on the analysis of soil organic carbon profile distribution in buried soil horizons and their comparison with analogous horizons of zonal Chernozems, as well as on the calculation of the mean depth of the parent material (197 ± 19 cm), the lower boundary for sealed soils was set at 200 cm. This depth makes it possible to account for the entire humus-accumulative profile and obtain more comprehensive results. The mean soil organic carbon content amounted to 1.70 ± 1.86% and 0.75 ± 0.55% for the upper technogenic and buried horizons, respectively. Specific stocks (per unit area) of organic carbon in the studied layer of sealed soils of the Rostov agglomeration averaged 178.18 ± 24.11 t/ha. The contribution of the upper transformed Urbic (UR) horizons to the total carbon pool was estimated at 30–40% (73.13 ± 63.57 t/ha). The obtained data provides an assessment of the scale of organic carbon reserves in urbanized environments and their contribution to the overall carbon pool. The results of the study may be useful for understanding the processes of accumulation and transformation of organic carbon in urban conditions, as well as for developing measures aimed at conserving and restoring soil organic carbon in urbanized areas.

This paper presents the research results on the effect of chemically modified biochar on the morphometric parameters of spring wheat in a vegetation experiment. It was found that biochar saturated with superphosphate (B+Pс) exhibited a synergistic effect. Its application at rates of 60 and 90 kg/ha resulted in an increase in shoot length by 24.0% and 30.0%, respectively. The B+Pс/60 treatment showed the maximum root length (16.8 cm) and root mass (2.25 g), indicating enhanced phosphorus availability and improved root growth conditions. The application of a high dose (150 kg/ha) was found to be impractical. The use of unmodified biochar showed a lesser effect. The use of superphosphate-saturated biochar will allow for a reduction in mineral fertilizer rates without a loss of efficiency. The obtained results should be evaluated in a field experiment.

In the vegetation experiment, the growth-stimulating effect of various doses of innovative «NanoSilicon» nanosilicon fertilizer was evaluated when growing Agrofac winter wheat on ordinary carbonate chernozem. Studies have shown that the treatment of winter wheat seeds with «NanoSilicon» at a dose of 300 g/t increased the growth rate by 8,0 % and the biomass of seedlings by 10,0 %. At the same time, the treatment of seeds with nano-fertilization at a dose of 450 g/t had the greatest effect on the length of winter wheat shoots. The growth-stimulating activity of «NanoSilicon» at a dose of 600 g/t has not been recorded. The studied biometric indicators in this variant were at or below the control level. The results showed that the treatment of winter wheat seeds with «NanoSilicon» at a dose of 300 g/t is the most effective not only for increasing germination, but also for stimulating initial growth and accumulation of biomass in the early stages of winter wheat ontogenesis, which in the future may create the basis for the formation of higher plant productivity.

The article presents the results of a study on the effect of IZAGRI fertilizers on the yield and fruit quality of apple trees in the Priazovye natural-agricultural zone of the Rostov region in 2024. The soil of the experimental plot was a weakly humus, clayey, carbonate-rich ordinary chernozem formed on yellow-brown clays. The study examined two apple cultivars: Santana and Gala Dark. IZAGRI fertilizers demonstrated cultivar-specific effects: in Santana, they increased yield (by 1.3 t/ha) while reducing average fruit weight under higher fruit load conditions; in Gala Dark, they improved fruit size while decreasing the average number of fruits per tree without significantly affecting yield. No significant differences in biochemical composition or marketable fruit quality were found between the treated and control groups for either cultivar. The obtained results suggest that foliar fertilization with IZAGRI can be recommended for intensive apple orchards grown on ordinary chernozems. For the Gala Dark cultivar, the effectiveness of the fertilizers requires further clarification, considering economic feasibility.

The article is devoted to the assessment of the effect of liquid mineral fertilizers on the dynamics of mineral nitrogen in ordinary chernozem when growing winter wheat using the resource-saving soil-protective no-till technology for 2023-2024. In the production experiment, LCF 11:37 was used at doses of 100, 150 and 200 l / ha against the background of two top dressings of CAM -32 in the spring tillering and tube emergence phases of 200 and 150 l / ha, respectively. The use of CAM -32 and LCF 11:37 in winter wheat crops allow to improve the nitrogen regime of ordinary chernozem and more fully realize the genetic potential of the high-yielding Alekseich variety. The maximum yield was obtained with the application of LCF at a dose of 200 l / ha against the background of two top dressings - 36.9 c / ha, which is 62.0% higher than the control. The results of the study indicate the need to use liquid fertilizers and urea nitrogen to increase the productivity of winter wheat agrocenoses in the no-till system.

The paper presents the results of a study on model soil sites of 30 km of the observation zone of the Rostov NPP. In Gleyic Fluvisols soil on alluvial buried sediments in a 0-10 cm layer, when selected using a 10 by 10 m grid, the coefficients of variation are: humus content - 33%, pH - 2%, cation exchange capacity - 12%, physical clay content - 6%, specific activity ¹³⁷Cs - 68%. In Gleyic Kashtanozem, the humus content - 19%, the pH - 5%, the cation exchange capacity - 12%, the physical clay content - 3%, and the specific activity of ¹³⁷Cs - 28%. A strong positive correlation in Gleyic Fluvisols and Gleyic Kashtanozem soils is inherent in the specific activity of ¹³⁷Cs in relation to the content of humus, physical clay and EKO. A moderate negative correlation is observed in Gleyic Kashtanozem soil between the specific activity of ¹³⁷Cs and soil acidity. The same factor in Gleyic Fluvisols soil is characterized by a strong negative correlation (r=-0.77).

The article presents the results of a study on the vertical distribution of carbon, nitrogen, and metal elements in permafrost soils and parent materials on the central Qinghai Tibet Plateau. Soil samples were collected at three sampling sites in the permafrost affected region, with subsequently analysis of soil organic carbon, total nitrogen, and metal elements contents conducted at soil depths of 0–500 cm. Comparative analyses were conducted between shallow (0–100 cm) and deep (200–500 cm) soil layers. The results demonstrate significant differences in soil physicochemical properties between shallow (0–100 cm) and deep (200–500 cm) soil horizons. Metal concentrations vary widely along the soil profile, with significant positive correlations observed among most metal elements. Additionally, soil properties such as pH, C/N ratio, soil inorganic carbon, and electrical conductivity show negative correlations with metal elements. The findings indicate that the shallow soil layer is substantially altered by pedogenic processes and cryoturbation, whereas the deep soil layer primarily retains the characteristics of soil parent material, with metal redistribution regulated by long term low temperature and redox conditions. These results provide valuable new data for environmental monitoring in the cryosphere of central Eurasia.

Field full-scale experiments on approbation of leaf - and soil diagnostics at different vegetation stages of lawn grasses were conducted on the basis of the experimental station for studying soil constructions. It is shown that the gross content of N, P and K in the ground part of plants in the artificially supported tillering phase corresponds to the median values of these elements inherent in Festuca rubra. This fact proves that application of 5g N/m2, provides normal development of lawn grasses during the season, without provoking explosive growth of the above-ground part of plants in the spring-summer period. Despite the relatively high content of organic carbon (3.1%) in the root-habitat layer of individual structures, which can be considered sufficient for lawn grass growing conditions, there is still a deficit of available mineral forms of nitrogen, which emphasizes the need for an integrated approach to soil diagnostics to ensure the attractiveness of lawns.

The article presents the results of studies on the effect of liquid mineral fertilizers on the content of ammonium and nitrate nitrogen in ordinary chernozem by the phases of pea development for 2022–2023. It has been established that the use of liquid mineral fertilizers (CAM-32 and LCF 11:37) when growing peas using no-till technology helps to improve the nitrogen regime of ordinary chernozem. The content of ammonium and nitrate nitrogen in the soil by the phases of pea development depends on the type of liquid mineral fertilizers and their dose. The greatest impact on the level of mineral nitrogen in the soil is provided by the combined use of CAM and LCF at a dose of 100 l/ha. Optimum conditions of the soil nitrogen regime in the fertilized variants were maintained throughout the entire period of pea vegetation, which confirms the prolonged action of LCF and CAM. The results obtained prove the feasibility of using liquid mineral fertilizers to increase the fertility of ordinary chernozems in the no-till system.

This study investigates the group composition of Zn compounds in calcic chernozem under cherry cultivation. It was found that Zn distribution in the soil profile exhibits an accumulative pattern driven by biogenic processes. A positive correlation exists between exchangeable and complexed Zn compounds and humus content. Weakly bound Zn compounds were negatively correlated with CaCO3 content and soil solution pH. The identified peculiarities of Zn group composition in calcic chernozem should be considered when optimizing mineral nutrition for fruit crops.

The research was carried out in 2019-2022 in a long-term field experiment on the erosion-prone slope of the southeastern exposure with a steepness of up to 3.5-4° of the Bolshoy Log gulch in the Aksai district of the Rostov region. The agrophysical and agrochemical properties of ordinary chernozem in pure steam and under winter wheat sown according to various precursors were studied. The aim of the work was to identify the most significant parameters of soil fertility for winter wheat cultivation. Based on the analysis of the main components of the distribution of agrophysical and agrochemical indicators of common chernozems, four main components (GC) were identified, which described 83.1% of the total dispersion. The first main component characterizes the inverse dependence of agrophysical parameters (mesoaggregates, coarse and dusty fractions) on soil moisture. The second main component reflects the relationship between the agrophysical and agrochemical properties of the soil (water runoff, the number of water-resistant aggregates and the content of macronutrients, humus). The third main component reveals the relationship between the ridge, the water supply in the snow, water permeability and soil flushing. The fourth main component revealed a relationship between soil density and mesoaggregates. The proposed approach can be applied to identify the most significant parameters of soil fertility that are optimal for winter wheat cultivation.

The article presents the results of a study of the effect of the BIO-Don humic preparation on cytomorphometric parameters of common barley (Hordeum vulgare L.) under stress caused by phosphorus deficiency. The purpose of the work is to study the effect of BIO—Don on the structure of the root system and the leaf plate of barley. A hydroponic experiment was conducted with four treatments: 1) Control-1 (Pryanishnikov’s nutrient mixture), 2) Control-1 + BIO-Don (5 ml/l), 3) Control-2 ((Pryanishnikov’s nutrient mixture replaced by tricalcium phosphate), and 4) Control-2 + BIO-Don. Cellular structures of the root system and leaf blades of barley were examined. The results of microscopic root analysis demonstrated that the application of BIO-Don under phosphorus deficiency conditions led to a 6.7-fold increase in root cross-sectional area compared to untreated control. In leaf blades, the preparation mitigated the negative effects of phosphorus deficiency by reducing leaf thickness by 32.9% while increasing chlorenchyma cell density by 94.7%. The obtained data confirm that humic substances enhance plant phosphorus nutrition by facilitating the conversion of phosphorus into more plant-available forms, thereby stimulating root system development and optimizing the structure of photosynthetic tissues.

The study of replantozems in the Rostov agglomeration, including their morphological properties, carbon content, dynamics of carbon emissions, and physical characteristics, showed that the thickness of these soils varies from 10 to 34 cm, and under the layer of replantant there are often buried humus layers inherited from native chernozems. Anthropogenic inclusions are rare, but roots and stones can be found. The average organic carbon content (C org.) in the studied soils is 2.52 ± 0.51 %, which is lower than in chernozems of fallow areas (3.25 ± 0.94 %). The highest C org. content was recorded in the soil of Osenny Park (2.99 ± 0.31 %), and the lowest in Lokomotiv Square (1.83 ± 0.42 %). Carbon emissions increase from April to July, then decrease in August-September. The highest emission intensity was recorded at the Golf & Country Club "Don" site, due to regular maintenance and watering. The total porosity of the RAT horizons ranges from 33 to 48 %, which is close to that of natural chernozems (44 %). The granulometric composition of the RAT horizons is predominantly heavy loamy and similar to that in natural ordinary calcareous chernozems, with fractions of 0.25-0.05 and <0.001 mm predominating; however, light-textured replantozems also occur rarely. The compaction density in replanted soils is often high already below the replanted layer, which may negatively affect plant growth and erosion rocesses.

As a result of laboratory and field studies, it was found that with the joint introduction of straw, cellulolytic micromycetes and diazotrophs in the soil, the microbial community is reformed, the groups involved in the processes of active decomposition of the straw substrate and in the accumulation of nutrients for plants receive the greatest activity. The use of effective strains of Humicola fuscoatra in conjunction with Azotobacter chroococcum is able to replace 40 kg of the active substance of nitrogen fertilizers and increase the rate of decomposition of grain straw on leached chernozem under conditions of grain crop rotation. The most effective strain of diazotropha was identified, which, when plowed into straw soil together with a cellulolytic micromycete, contributes to an increase in sugar beet yield by 12.5% relative to the control.

The primary results of the joint Russian-Kyrgyz cooperation in the field of the implementation of the information system "Soil and geographical database of Kyrgyzstan" in the Kyrgyz Republic, where a national database on soil resources (Data Center) will be created, are considered. The data center is designed to communicate between primary digital resources of natural and soil information, data from soil maps stored in the funds of various organizations, regional centers of the soil and agrochemical service, and regional departments accumulating digital information necessary for making management decisions and ensuring food and environmental security of the country. The main stages of the formation of the primary set of cartographic material are determined: inventory, standardization of references and indicators’ lists, formation of a strategy for selective digitization and vectorization of legacy large-scale soil maps and reports, and obtaining a representative set of digital materials for the main soil-climatic and geomorphological regions of the republic. To structure the legends of soil maps and form classifier lists, the vectorization of the medium-scale soil map of the Kyrgyz SSR, compiled on a scale of 1:600,000 edited by A.M. Mamytov in 1959, was carried out, on the basis of which the reduction (correlation) of the soil reference list to the classification of soils of the USSR 1977 is considered. The features of georeferencing of soil maps in conditions of complex mountainous terrain using satellite digital terrain models are described. The implementation of the prototype of the agricultural and soil data center of the Republic of Kyrgyzstan is described as one of the nodes of the distributed network of soil data centers of the soil geographical database (SGDB RF), having a client-server architecture with three tiers (database server, Internet server, web applications and GIS applications), examples and illustrations of how applications work.

A literature review over the past 70 years of studies on changes in the chestnut soils and chernozems properties under the influence of irrigation is given. Emphasis is placed on the impact of rice crops under flooding, but attention is also paid to other types of irrigation. Irrigation is accompanied by significant changes in the chemical properties of soils: easily soluble salts dissolve and migrate along the profile, substitutions are observed in the soil-absorbing complex (SAC) and sodium is introduced into the SAC. Restructuring occurs in the system of humic substances, and with overwatering and rising groundwater levels, the redox regime changes up to the manifestation of gleying processes, the transformation of clay minerals causes the development of fusion. The most common changes occur in the composition of exchangeable cations, salt accumulation, and changes in the acid-base characteristics of soils. Even more profound changes are observed in the soils of rice fields. Gleying, lessivage, and leaching of carbonates, silt fraction, water-soluble humus, mobile iron and phosphorus from arable horizons, which are unusual for steppe soils, develop. The degree of transformation depends on the genetic properties of soils and the drainage state of irrigation systems. At the same time, chestnut soils turn out to be genetically more stable than chernozems, which is due to their mineralogical composition.

The article deals with the activity of ⁴⁰K, ¹³⁷Cs, ²²⁶Ra, ²³²Th in calcic chernozems and herbaceous plants growing it. Soils were studied within the Rostov agglomeration and in protected areas of the Rostov region. In order to calculate the removal and accumulation coefficients, weighted average soil radioactivity was calculated for 10, 30, and 100 centimeter thicknesses at the sites where plant samples were taken. The coefficient of biological accumulation of ⁴⁰K and ¹³⁷Cs in herbaceous formations formed on natural soils of the city and soils of SPNA exceeds 1, which indicates their accumulation by above-ground parts of plants. At the same time, there is an increase in IPM with the increase in the calculated thickness of the rooting layer. The biological uptake coefficients of ²²⁶Ra and ²³²Th for all studied soil-plant systems are close to zero.

The article proposes to consider the state of forest belts when conducting an agroecological assessment of soils for the steppe zone. One of the methods for such an assessment is the calculation of the standard yield of grain crops in accordance with the methodology for calculating the standard yield, approved by order of the Ministry of Economic Development of Russia dated September 20, 2010, No. 445. The basis for calculating the indicator is correction factors, the value of which depends on soil fertility (humus content in the arable horizon and A + B thickness), granulometric composition (physical clay content), and negative signs (salinization, alkalinity, stoniness, etc.). For the Rostov region, it is proposed to add a correction factor for the state of forest belts, since they prevent the development of erosion processes in the fields, create optimal conditions for the growth of agricultural plants and, in general, help maintain soil fertility. For fields with an absent or sparse (not fulfilling their function) network of forest belts, the yield of grain crops is reduced by 15-20%. At the same time, forest belts, the safety of which is 65% or more, extend their protective effect at 200-250 meters from themselves, and forest belts that have survived less than 65% of their original area extend their protective effect at less than 150 meters. Therefore, for the territories corresponding to the former USSR farms, where there is a decrease or increase in forest belts due to overgrowth of forest belts with shrubs (which also reduces the protective function of field-protective forest plantations due to a decrease in the height of the structure), by less than 35% (preservation of forest belts). bands – 65% or more), then a reduction factor of 0.8 is assigned. For sites where the forest belts are less than 65% preserved, a coefficient of 0.5 is assigned, since there is a significant decrease in the effectiveness of the forest belt. If there is no significant change in shelter belts in comparison with the period of the USSR, when the optimal state of forest belts was maintained, a leveling coefficient of 1 is assigned.