№ 2 (2025)

In a four-year field experiment, the effect of applying biochar at a dose of 20 t/ha on the content of total organic carbon (TOC), dispersed pool carbon, carbon of mineral-associated organic matter and carbon of the clay fraction of the soil (C_clay) was studied. The field experiment was carried out at the Agrophysical Station of the Menkovo Experimental Station (Leningrad Region). The agricultural plot is occupied by sod-podzolic sandy loamy soil, which differed in the degree of cultivation: medium cultivated (MC) and highly cultivated (HC). Experiment scheme: control (without biochar) and soil with biochar at a dose of 20 t/ha. The content of C_org was determined using the Tyurin method. Isolation of the dispersed pool (POM) and mineral-associated pool (MAOM) was carried out according to the following procedure. 30 ml of sodium hexametaphosphate solution (Na₆P₆O₁₈) (5 g/l) was added to a soil sample weighing 10 g, passed through a sieve with 2 mm mesh, then shaken on a shaker for 15 hours (speed 180 rpm). The resulting suspension was passed through a sieve with a hole diameter of 0.053 mm. The POM fraction was collected on a sieve, and the MAOM fraction was collected under the sieve. Isolation of the clay fraction of the soil was carried out by sedimentation after treating the samples with ultrasound. As a result of a 4-year experiment, when biochar was added, there was an increase in C_org content in medium cultivated soil by 2.8%, in highly cultivated soil by 21.3%. An increase in the mass of POM in the variant with biochar of medium cultivated soil by 8% was observed; in highly cultivated soil with biochar, on the contrary, a decrease in the POM content by 4% was observed, compared to the control. Biochar contributed to increasing the carbon content of the dispersed pool. The carbon content in the dispersed pool of MC soil increased by 15%, and of HC soil by 20.8%, compared to the control. The addition of biochar led to a decrease in the mass of the MAOM pool in the 4th year of the study in medium cultivated soil by 17.6%, and an increase in its content in highly cultivated soil by 16.5%. Biochar contributed to a decrease in the carbon content in the MAOM pool in MC soil by 20.8%, and an increase in its content in HC soil by 25.5%, compared to the control option. Biochar contributed to an increase in the content C_clay in terms of soil weight in medium cultivated soil by 4%, in highly cultivated soil by 6.8%. In the fourth year of the experiment, the effect of biochar weakened.

The efficiency of using nitrogen, phosphorus and potash fertilizers (N90, P90, K90, N90P90, N90K90, P90K90, N90P90K90, N30P30K30, N60P60K60, N120P120K120, N150P150K150) in a long-term experiment (year of establishing– 1978, Permian Research Institute) on sod-podzolic heavy loamy soil in a field 8-pole crop rotation was evaluated. It was found that in the climatic conditions of the Urals, the use of N90 on winter rye and oats was the most effective (taking into account the payback of 1 kg of a.s. NPK with 1 kg of main products), on potatoes – (NPK)30–60, spring wheat – N60P60K60, barley – N30P30K30. There was no significant effect of mineral fertilizers on the yield of meadow clover hay of the 1st and 2nd year of use. Crop rotation productivity increased by 12–25% on average over 5 rotations when using N90, N90P90, N90K90, P90K90, and (NPK)30–150. The maximum productivity was obtained in the N60P60K60 variant – 3.31 tons of grain, the highest payback was achieved when applying nitrogen fertilizers N90 (8.9 kg of grain). At the same time, prolonged use of the mononitrogen fertilizer system led to a deterioration in soil fertility. The use of superphosphate and potassium chloride in its pure form did not significantly affect the productivity of crop rotation. The balances of organic carbon and mineral nutrition elements were calculated. A positive carbon balance was obtained using high doses of N120P120K120 and N150P150K150 (+0.06–0.13 t/ha/year), only in these variants the maintenance of the C_org content in the soil layer (0–20 cm) at the initial level was noted. The nitrogen balance, which is close to zero and positive, was formed when nitrogen fertilizers were applied at a dose of 90–150 kg a.s./ha. A positive phosphorus balance was obtained by applying superphosphate at a dose of 60 kg a.s./ha and more. A zero and positive potassium balance was formed when potassium chloride was used at a dose of 120–150 kg a.s./ha.

In a study conducted in 2022–2023, it was found that the use of reduced norms of anti-inflammatory and anti-slag drugs in combination with Stikk adhesive in crops of domestic sugar beet hybrids had high biological efficiency and contributed to the yield of root crops 44.8–46.4 t/ha (no less than when using the full norm of herbicides – 44.2–46.4 t/ha) with high sugar content (17.0–17.7%). Reduced herbicide rates by 10% in combination with both Karibou and Goltics provided the greatest agronomic efficiency in both crops of the RMS 120 and RMS 127 hybrids. The maximum economic efficiency of using these standards was noted in crops of the RMS 127 hybrid. The use of 10% reduced norms of betanal group herbicides and anti-slag drugs in combination with the Stikk adhesive, as well as with the Goltics and Karibou solutions, when cultivating domestic hybrids, allowed to save 1.3–4.7 thousand rubles/ha.

In a long-term stationary experiment on sod-podzolic sandy loamy soil in the Leningrad region, it was shown that the negative effect of soil fertility reproduction means on the phytosanitary condition of potato plantings and harvested crops was manifested only in an increase in the infestation of tubers with scab (1.5 times – the proportion of affected tubers, 1.3 times – the intensity of the lesion). As a result, there was an increasing need for measures to protect planting material from this disease. Positive changes in the phytosanitary parameters of the potato agrocenosis under the influence of soil cultivation were associated with a decrease in the damage to tubers by larvae of click beetles (by 1.2–1.3 times), with the introduction of a complete mineral fertilizer – with a decrease in the intensity of damage to potato plants by alternariasis (by 3.0–3.5 times), damage to plants and tubers by rhizoctoniosis (1.1–1.5 times and 1.2–2.1 times, respectively), damage to plants by larvae of the Colorado potato beetle (1.7–2.0 times). The defeat of tubers by scab and damage to tubers by larvae of click beetles depended more on the degree of cultivation of the soil (by 33.7–48.1 and 4.5–5.7%) than on the level of fertilization of potato plantings. Nevertheless, the contribution of fertilization was of decisive importance in the defeat of potato with alternariasis (76.9–77.7%) and rhizoctoniosis (8.9–18.0%), as well as damage by the Colorado potato beetle (7.0–10.4%). The influence of the studied means of reproduction of soil fertility in relation to damage to potato tubers by caterpillars of gnawing scoops was not sufficiently pronounced, which was not statistically confirmed.

In small-scale field experiments, the effect of pre-sowing seed treatment with montmorillonite K-10 on the yield of green corn mass was studied. Experiments in 2022 and 2023 showed an increase in the yield of green mass, including cobs, up to 50%. In the 2023 field season, experiments were conducted with 2 varieties of corn Phenomenon and Krasnodar 201 AMV. In both cases, the yields did not differ significantly. The results obtained create the prospect of widespread use of montmorillonite for pre-sowing seed treatment.

Nitrogen monoxide in fungi participates in the processes of reproduction, pathogenesis and adaptation to environmental conditions. Substances that affect the NO content in fungal cultures have an effect on growth processes and the synthesis of other metabolites. The effect of a donor and an inhibitor of NO synthesis on the production of stress metabolites of basidiomycetes Lentinus edodes and Grifola frondosa under abiotic stress conditions (high- and low-temperature shock, lack of carbon and/or nitrogen in the nutrient medium) was studied. Under all the conditions studied, the introduction of L-NAME (NO synthesis inhibitor) into the medium stimulated, and SNP (NO donor) suppressed the growth of fungal mycelium. At the same time, the content of the protective stress metabolites trehalose, mannitol and proline in both basidiomycetes increased to 70% in media with SNP and decreased to 65% in media with L-NAME. The most pronounced effect of SNP and L-NAME on the growth of fungal cultures and their accumulation of protective compounds turned out to be under the influence of temperature stress.

The ability of natural isolates of the phytopathogenic micromycete Microdochium nivale (Ascomycota), which causes snow mold in agricultural plants, to biodegradate anthraquinone, anthracene-like and diamino triphenylmethane dyes when cultivated in submerged culture has been established. The degree of biodegradation depended on the type of dye and the strain of the mushroom culture, the greatest biodegradation ability was observed in relation to malachite green, the discoloration of the dye was up to 65%. Neutral red was discolored by the enzymes of the studied ascomycetes by 28–40%, remazole brilliant blue – by a maximum of 26%. The most intensive biodegradation of diamino triphenylmethane and anthracene-like dyes was noted in the first 4 days after the introduction of dyes into the growing medium (8-day M. nivale cultures). The bleaching of the anthraquinone series dye took place gradually from day 1 to day 28 of cultivation. Correlation between the dynamics of biodegradation of dyes by M. nivale strains and enzyme activity of the ligninolytic complex of this ascomycete indicated a key role in the process of extracellular lignin- and Mn-peroxidases. Given the ubiquity of fungi from the Ascomycota department, the high activity of phenolic oxidizing enzymes and their potential in the decomposition of a wide range of aromatic compounds, micromycetes can become active objects in the industrial bioconversion of lignocellulose, the paint and textile industries, as well as be used for environmental bioremediation.

Organoglines are clay minerals modified by intercalation, or grafting, of organic molecules, which have a generally hydrophobic surface character and can be used to absorb and fix organic and inorganic pollutants. The review examines the main mechanisms of interaction of organic modifiers with clay minerals with an expanding structural cell and the most common methods of organoglycan synthesis. The properties of various types of surfactants (cationic, anionic, amphoteric and nonionic) affecting their absorption on clays are described. Data on the absorption of cationic forms of heavy metals by organoglycans based on various types of surfactants are presented. Despite the nonpolar nature of the surface of organoglycans, some of them can effectively absorb metal cations.