The prospect of adapting two methods for monitoring the fertility of agricultural soils (humus balance, HB) under spring and winter wheat crops (hereinafter referred to as grain crops) developed in the Russian Federation (RF) for the purposes of climate projects has been studied. It was revealed that the RosNIIzemproekt method (1998) underestimates the HB average value to
-7.7 c/ha for RF. The RosNIIzemproekt method (1998) has logical errors in the calculation model and is not recommended for use. The TsINAO method (2000) has a more logical calculation model. According to this method, the average value of HB in soils for RF is generally positive and amounts to 3.3 c/ha (0.71 tCO₂-eq/ha carbon units). This value constitutes ≈0.3% of average humus reserves in arable soils of the RF (108 tС/ha). The annual value of change in humus content under spring and winter wheat is incommensurably less than the total humus reserves in the soil. Statistically reliable assessment of changes in humus content requires a huge number of soil samples. This makes the verification procedure economically inexpedient. Another option is proposed to increase the time of humus accumulation. It is considered (IPCC, 2003) that a 20-year accumulation period is sufficient, which corresponds to the duration of soil climate projects. A coefficient (0.216) has been proposed for converting humus reserves (c/ha) to the value of a carbon unit (tCO₂-eq/ha). The total sequestration of carbon by soils under grain crops in 2022 was about 11 million 914 thousand tCO₂-eq. HB accounting significantly compensates for calculated emissions from agricultural production and reduces them by almost 10% (from 116 to 105 million tons CO₂-eq in 2022). For both models of fertility monitoring, an assessment was made of the quality of the regression dependence of HB on the total biomass of photosynthesis (TBP) in soils under grain crops. It is shown that according to Fisher's t-test at a 5% significance level, the studied relationship is significant and characterized by the squares of the correlation coefficient (R²) equal to 0.554 and 0.998. In accordance with the Chaddock scale, the closeness of the correlative relationship between HB and TPB for winter wheat is assessed as high, and for spring wheat as very high. 

The goal of this work is to analyze the dynamics of soil organic matter (SOM) in arable soils of Yamal using computational experiments with the ROMUL model. Soil temperature and moisture dynamics were simulated using the SCLISS model. The Yamal experimental station was organized in 1932. The soil is Plaggic Podzol. The thickness of humus horizon (PY) is
30 cm. Pools, kg/m²: SOM – 9.32 and 13.75; N – 0.46 and 0.66 for 0–20 and 0–30 cm respectively. Background: soddy-green-moss tundra near Salekhard. Soil: Folic Podzol: litter (O, 2 cm) and humus-accumulative (AY, 4 cm) and illuvial ferruginous (BF, 6 cm) horizons. Pools, kg/m²: SOM – 1.38 and 2.69, N – 0.03 and 0.18 for 0–2 and 2–6 cm respectively. The quantity and quality of background fall was estimated according to literature data. Clarification of the amount of fall was carried out by the method of inverse problem solving (spin-up). Peat application was simulated: starting application in the dose of 12 kg/m² and maintenance (every 6 years) in doses 4, 8 and 12 kg/m², N 1%. Application of mineral fertilizers, 2 variants: a) N 4 g/m² (40 kg/ha) in peatting years and b) application of the same dose of nitrogen every year. The duration of computational experiments is 30 and 90 years. Computational experiments showed that after the starting peatting of Folic Podzol at the rate of 12 kg/m² after 30 years, only 15% of the applied detritus remained. Maintenance peatting of 8–12 kg/m² leads to an increase in SOM pool to 20–30 kg/m² and excessive accumulation of detritus. Application of 4 kg/m² of peat once every 6 years for 90 years shows the dynamics of SOM pools from Folic Podzol to Plaggic Podzol which is confirmed by field survey data. Application of mineral nitrogen (4 g/m²) once every 6 years does not affect SOM pools. Annual application of mineral N (4 g/m²) increases SOM pools due to intensified humification. This fact requires experimental verification.

By the example of studying the Early Holocene paleoalluvial soil (ancient man's site in Akhtsu Grotto, an overflow terrace of the middle reaches of the Mzymta River, Sochi Black Sea region), the efficiency of using a set of microbiological methods revealing the conditions of formation of the ancient paleoobject and the genesis of the geomorphology of the river valley was shown. The study of morphology and mesomorphology of the palaeo-soil allowed to assume its possible formation under the conditions significantly more hydromorphic in comparison with the modern ones. It is probable that earlier, at the beginning of the Holocene, this area was not a terrace, but a near-terrace, over-watered part of the river floodplain. Microbiological characteristics confirmed this assumption. The composition of the microbial community was identified from the isolated soil DNA of prokaryotic microorganisms (bacteria and archaea) by DNA metabarcoding. Groups and species of microorganisms-indicators reflecting the specificity of genesis of the studied soils were identified. Microbiological indicators of overwatered conditions were representatives of the phylum Planctomycetes of Phycisphaerae and Planctomycetia classes dominant in the microbiome (more than 1% of total DNA) and cyanobacteria of Chloroplast class of Streptophyta, Stramenopiles and Pseudanabaenale orders, as well as archaea (0.5% of total DNA) of Euryarchaeota phylum; Thermoplasmata class; Methanomassiliicoccaceae family, capable of methanogenesis. This species was not found in the microbial complex of the modern background soil. Indicator microorganisms identified as part of the prokaryotic community of palaeo-soils may potentially have useful applicable properties. 

A complex of soils characteristic of the Vladimir Opole region was studied: agro-gray typical deep-arable soil, tongue-shaped agrozem and agro-gray gleyic soil. The high contrast of soil properties, which is due to the genesis of field landscapes, can be traced in the differences in the arable and subarable horizons of agro-gray soils at the aggregate and microaggregate levels. The soils have an excellent structural condition, high water resistance and mechanical strength of aggregates. In the aggregate structure of arable horizons, dependences on the position in the relief were found: down the slope the content of agronomically valuable aggregates decreases, the weighted average diameter of aggregates increases, the water resistance of aggregates and the mechanical strength of aggregates at capillary saturation decreases. However, the distribution and size of microaggregates, as well as the strength of aggregates in an air-dry state, reflects the complex genesis of the landscape and retains the influence of paleorelief with depressions and elevations. The weighted average diameter of microaggregates of arable horizons of the soils of the Vladimir Opole region is close to the chernozems of the Kursk region. The granulometric composition of the studied soils is typical of Vladimir Opolye soils and close to each other. In accordance with the classification of N.A. Kachinsky arable horizons are medium loamy, coarse silt, BT horizons are heavy loamy, coarse silt. The most structural is the arable horizon of agro-gray typical deep-arable soil, it has large microaggregates, it also has high water resistance and the highest content of agronomically valuable aggregates. The most homogeneous in terms of aggregate composition is tongue-shaped agrozem; the average diameter of aggregates and microaggregates in the arable and subarable horizons are equal and similar in the content of microaggregates and agronomically valuable aggregates. This soil is also highly water resistant. Agro-gray gleyic soil contains fewer agronomically valuable aggregates and its water stability is unsatisfactory.

Manufacturers of agricultural machines, when designing, pay a little attention to its impact on soil, thus producing models with high compression loads on the soil or with a small contact area between the tyres/tracks and the soil surface. Therefore, the aim of this study is to evaluate the negative impact of both wheeled and tracked agricultural tractors on the soil, in terms of soil compaction, and its causes (i. e. design features of tractor tyres/tracks), during the last six decades (i. e. from 1961 to 2021). Soil compaction is caused by the pressure applied by agricultural machines on the soil through the contact area of their tyres/tracks with the soil surface. So, the main indicator of the negative impact on the soil by the tractors manufactured during the last 60 years, i. e. the average pressure applied by the tyres or tracks of tractors manufactured in EU and in the post-Soviet cuntries from 1961 to 2021 to the soil, was computed. A general decrease of the average pressure of the tyres/tracks on the soil can be observed in 1980s and 1990s, followed by its general increase since 2000, above all for the tractors having power higher than 140 kW. Thus, there is an urgent need to assess spatial and temporal changes in soil vulnerability to compaction, that depends on weather conditions and soil properties, as well as agricultural management practices, and can only be fully assessed by means of a combination of traditional techniques (i. e. use of soil cone penetrometer followed by 2D mapping using GIS or 3D mapping through geostatistics) and mechanical approaches (i. e. computation of agricultural machine parameters – soil contact area). The results show that tractor manufacturers did not take care of reducing soil compaction during the considered period. 

: The article is devoted to the study of zinc, copper, and lead content in the soils of Rostov-on-Don. Soil samples were collected from full-profile sections located in different districts of the city and suburbs of Rostov-on-Don. The group of anthropogenically disturbed soils included Urbic Technosol urbanstratozems and replantozems, as well as urbanized chernozems Calcic Chernozems (Technic). Natural soils of recreational areas are represented by migration-segregation chernozems Calcic Chernozems (Pachic). The study was carried out using atomic absorption spectrometry and X-ray fluorescence analysis to determine metal content. Soil structure was determined by the Savvinov method (dry sieving) (<0.25; 1–2; 3–5; 5–7; >10 mm). Statistical analysis of the Wilcoxon criterion for related samples was performed to identify relationships. The main objective of the study was to assess the heavy metal content in different size fractions of aggregates and the ability of structural fractions to accumulate zinc, copper, and lead. Structural aggregates of different sizes differ in their ability to accumulate zinc, copper and lead. Zinc, including its mobile compounds, is predominantly accumulated in microaggregates. The content of gross copper and especially lead is confined to larger aggregates. At the same time, mobile copper compounds are concentrated in microaggregates and in fractions larger than 10 mm. Mobile lead compounds are distributed in fractions of different sizes quite uniformly in all studied soils.

: For the first time, polycyclic aromatic hydrocarbons (PAH) contamination of the soil cover of Ulan-Ude, the capital of the Republic of Buryatia, was studied. The content of 16 individual polyarenes was analyzed in the upper horizon of background chestnut and urban soils, sampled during soil and geochemical survey in July–August 2022. The average concentration of total PAHs in the soil cover of Ulan-Ude was 735 ng/g, which was 8 times as much as the concentration in the background soils (87 ng/g). The PAH amount in the soil of various functional zones decrease in the following order: railway transport > motor traffic > industrial > one-story residential > multi-story residential > recreational. At the same time, the amount of PAHs in the railway transport zone was 2.6–5.2 times higher than in other functional zones, which indicates that railway transport is the most powerful source of PAHs in the city. Contamination of soils with polyarenes in all functional zones is determined primarily by medium- (46%) and high-molecular-weight (41%) compounds. Among PAHs with low molecular weight, phenanthrene prevailed (9% of the total PAHs), but medium-molecular-weight fluoranthene (18%) and pyrene (13%) showed higher share; high-molecular-weight compounds dominated by benzo(ghi)perylene (12%), benzo(b)fluoranthene (10%), indeno(1,2,3-cd)pyrene (8%) and benzo(a)pyrene (6%). The total amount of 16 PAHs in the soil cover of the city varied within the range of 17–9 540 ng/g. The highest levels of pollution (3 226–9 540 ng/g) were recorded at 9 sampling points (4% of the city), which form the most contrasting local PAH anomalies. In more than half of the territory of Ulan-Ude, the total amount of PAHs did not exceed 500 ng/g. The indicator ratios of individual PAHs made it possible to determine the dominant types of sources, which include railway transport and coal combustion. The contribution to the environmental hazard of soil contamination with PAHs in Ulan-Ude was mainly made by benzo(a)pyrene (64%) and, to a lesser extent, by benzo(b)fluoranthene (9.6%), indeno(1,2,3-cd)pyrene (7.2%), dibenzo(ah)anthracene (6.5%) and benzo(a)anthracene (6.1%).

The search for new technologies for effective regulation of yield and soil fertility is an urgent task. The use of slow-release fertilizers can simultaneously solve both problems – reducing fertilizer rates and increasing the mobilization of soil nutrients. In this paper, the mechanism of slow-release fertilizer effect on the mobilization rate of soil nutrients was investigated using mathematical modeling on the data of field trials with winter wheat. It is shown that in the plots with the slowest dissolving fertilizer (azofoska with 20% content of polyvinyl alcohol), the highest efficiency of azofoska was achieved (an increase in yield of 1.3 t/ha and an increase in mobile forms of phosphorus in the soil of 2.5 mg/100 g soil, potassium – 8.8 mg/100 g soil and nitrate nitrogen – 4.7 mg/100 g soil). The results of phosphorus modeling quantitatively confirmed the assumption that the low rate of dissolution of fertilizer enhances the mobilization of nutrients from soil due to the absence of an excess of plant available nutrients. We provide estimates of the polymer added efficiency for a series of polymer-modified fertilizer. It is shown that this form of fertilizer can be applied to effectively reduce the amount of fertilizer required for the planned harvest, simultaneously with the possibility of bringing the soil to a higher level of effective fertility in major nutrient elements.

To solve environmental problems and reduce economic costs, it is necessary to improve mineral fertilizer application systems by developing and introducing new technologies, including the use of biochars. Due to the lack of effective monitoring of soil changes, it is difficult to adjust fertilizer application rates. This determines the importance of information on the elemental composition of biochar ameliorants used to reduce the mobility of heavy metals in the soil. The use of biochar for remediation of contaminated soils is based on its ability to immobilize heavy metals and organic pollutants. In this work biochars were used, obtained by slow pyrolysis of organic materials of different types: pine sawdust, cattle manure, wheat straw, pine nut shells and brewer's grains. The effect of biochars (biochar application at a dose of 10 t ha⁻¹) on the concentration of 13 elements (C, N, K, P, Mg, Ca, Fe, Mn, Pb, Ni, Cr, Cd, Co) in the soil was analyzed. The data collected after growing of spring wheat (Triticum aestivum L.) on the sod-podzolic soils were analyzed. It has been established that the heavy metals concentrations in the studied soils reclaimed with biochars are significantly lower than the maximum allowable concentrations for soils (MAC). The content of lead (Pb) in soils treated with biochars is 9 or more times lower than the MAC level, and biochar, produced from manure, significantly reduces the concentration of this metal in the soil.

The results of research on properties of cinders obtained by high-temperature roasting of clay-salt waste (sludge) after processing K-Mg ores are presented. Cinders are used as complex fertilizers, ameliorant components and microelement fertilizers. Secondary wastes, after extraction of Pd, Pt, Ag from burnt sludge (cinder), consist of sludge after deslagging of crushed cinder and “tails” after sand enrichment. Mixing these products, moistening, granulating and sintering forms result in a sintering product (CP) that is ready for application as complex fertilizer, ameliorating additive and microfertilizer. A study of the chemical composition and composition of impurities of cinders and CP was carried out. The identity of the composition of cinders and CP has been established. Tests with cinders and CP as a complex of fertilizers, ameliorants and microfertilizers were carried out. The research was carried out on the experimental field of Perm Agricultural Research Institute, on sod-podzolic heavy loamy soil formed on the deluvium of Permian clays, this soil represents up to 70% of the arable lands of the Perm region, the studied crop was potato. The yield of potato when applying cinder as an ameliorant additive was higher by 6.05 t/ha compared to the control (the use of traditional fertilizers provided an increase of 3.56 t/ha). For the first time determination of chemical composition including trace elements studies was fulfilled in potato tubers from unfertilized variants, plots fertilized with traditional fertilizers and plots fertilized with cinders. Two components of tubers – peel and pulp – were analyzed using a mass spectral method, with decomposition in a closed system (autoclave). Most of the elements were characterized by a higher content in the peel (almost an order of magnitude) compared to the pulp. An inverse relationship was observed for P and S, their content was higher in pulp than in peel. In the variant with the use of cinder, a higher content of microelements, especially rare-earths elements, was observed compared to the control. A method for processing sludge to extract Pd, Pt, Ag, results in secondary wastes, that can be used as complex slow-release fertilizers, ameliorating additives and microelement-containing fertilizers.