A theoretical analysis of the influence of the source-drain on the dynamics of the sorption process for one particular (border-line) case is given for the non-classical mathematical model of the process of water vapor sorption by the soil surface with a source-drain developed by the authors. Unlike the model of M. Griesmer, in which the sorption equation is homogeneous, in the proposed model the sorption equation is heterogeneous – there is a constant non-zero free term, which is considered as a parameter of external influence on the system (source-drain function). The parameter allows controlling the sorption process by changing its characteristics. The solution of the model equation determines the basic analytical relationship for analyzing the dynamics of soil volumetric water content as a function of time. The behavior of the volumetric water content function is determined by the influence of the selected parameter value as well as by the relationship between constant initial and equilibrium moisture, for which three variants are possible. As a result of studying the dynamics of soil system volumetric moisture according to the developed model, it has been established that in this case the sorption process will proceed in three modes: the first mode of the modeled process is a time-limited, finite process of critical soil drying; the second mode is a stationary process, when soil volumetric water content does not change over time and remains equal to the initial moisture (the process asymptotically degenerates); in the third case, the considered sorption model describes a time-unlimited asymptotic process of soil volumetric water content fall from the initial value to the limiting (non-zero) value.

   Soil-geobotanical survey of the main erosion-prone agricultural landscapes of the steppe zone of the Republic of Khakassia was carried out by laying six benchmark sites on the testing areas selected by the Earth remote sensing method. Based on the morphological description of the sections, the following soil types were identified: ordinary and southern chernozem, dark chestnut and chestnut soils. The projective coverage of ordinary black soil was 58 %, southern black soil – 35–66 %, dark chestnut soil – 60 %, chestnut soil – 40%. Vegetation cover on the arable soils is represented by cultivated and weedy vegetation, on the pastures – by herbaceous associations with fine- and sod forming plants of true steppes. Genetic horizons of the studied sections correspond to the soil type. Soil fertility is very low due to both soil formation factors and natural and anthropogenic digression processes. The close occurrence of carbonates from the surface (20–35 cm) with low precipitation and predominance of exudational water regime resulted in alkalinization of the upper (0–20 cm) soil layer. Calcium pre-dominates among the absorbed bases. Its content relative to magnesium concentration is 2.5 and 5.5 times higher on chestnut and chernozem soils, respectively. The most fertile soils formed in the most moistened Shirinsky steppe contain up to 3.3–3.4% of organic matter. In the soils of drier steppes in the southern part of the republic there is a decrease in organic matter content to 2.1–2.9%. The concentration of total nitrogen also varied in accordance with the organic matter content, ranging from 0.17–0.29 mg/kg. Medium and high degree of biogenic accumulation of mobile forms of phosphorus and potassium in the arable layer was noted. Thus, the correlation of mobile phosphate and potassium content with total nitrogen was 0.45 and 0.97, respectively. The average content of mobile phosphates was recorded in chernozems and dark chestnut soil (15.3–23.6 mg/kg), low – in chestnut soil. Potassium supply varied from very high in the soils of Shirinskaya steppe to high and elevated in southern chernozems and chestnut soils of Koibalskaya and Uibatskaya steppes.

   Oil flax (Linum usitatissimum L.) is a multi-purpose crop used in many industries. The composition of traditional flax seed oil varieties is characterized by a high content of desaturated Omega-3 fatty acids. In the process of lipid biosynthesis in the cell, an important step is the desaturation of fatty acids, which determines the final ratio of saturated and desaturated fatty acids in the oil. The main enzymes that determine the efficiency of desaturation are membrane-bound desaturases (FADs) and soluble desaturases (SADs).

   The purpose of the work is to study the expression of desaturase genes in the process of seed development of different oilseed flax varieties.

   Eight varieties of oil flax with different fatty acid composition of oil served as the material for the study. The samples were grown in a plant chamber until flowering and on days 5, 10, 15, 20, 25, 30 and 35 after flowering, bolls were taken from the plants followed by RNA extraction from the seeds. Then reverse transcription and semi-quantitative RT-PCR were performed. The resulting reaction products were separated using a 1.2 % agarose gel. The adenine phosphoribosyltransferase-1 (APT1) gene was used as a reference. As a result of the study, data were obtained on the expression of six flax desaturase genes: SAD1, SAD2, FAD2A, FAD2B, FAD3A and FAD3B. Evaluation of the expression of the SAD1 and SAD2 genes in all the studied varieties at all the studied stages of seed development did not find any differences. Expression of desaturase genes of the FAD2 family depended on the stage of seed development. During the studied period of seed formation, the expression level was high, indicating the intensity of biosynthesis and accumulation of α-linolenic and linoleic acids. The expression of FAD3 desaturase genes, which control the final stage of the conversion of flax desaturated fatty acids, did not significantly depend on the time after flowering. A proportional dependence of the content of α-linolenic acid in oil on the level of expression of the FAD3 desaturase genes was revealed. The data obtained indicate the dynamics in the metabolism of fatty acids during the formation of flax seeds. Genotype specificity was determined when assessing the expression of desaturases of the FAD family in oil flax seeds.

   The ways to reduce water inputs in the most water-intensive sector of agricultural production related to rice irrigation have been studied. In irrigated agriculture, it is the dominant and most water-intensive crop. Experimental data on weediness of rice crops irrigated with intermittent waterings depending on the preceding crops are presented. Every year weeds infest agricultural crops leading to a significant reduction in yields and crop quality. The results of the study make it possible to determine the species composition of weeds and weed control measures through the treatment of rice crops with a tank mixture of herbicides. Total water consumption of the crop by different forecrops has been determined. As a result of the observations, the main weed species have been identified, which included the following weed species: redroot amaranth, barnyard grass (prickly grass), corn bindweed and other representatives of the weedy vegetation. Soil herbicide Stomp (6.0 l/ha) was used in combination with treatment of the rice plants with a tank mixture of Cambio (2.5 l/ha) + Topik (0.5 l/ha) herbicides dissolved in 200 liters of water. Also in the work, the data on structural indices of rice plants on different forecrops are indicated, which allowed to establish the actual yield. As a result of the data obtained, it was established what forecrop is effective both for reducing weediness of crops and obtaining the highest yield of the rice plants in the variants of the experiment.

   The results of the studies on the formation of quantitative and qualitative composition of protein in millet of different varieties depending on meteorological conditions during the growing season and separate phases of vegetation are presented. The research was conducted in 2018-2020 in the Samara region on three samples of common millet groats: Povolzhskoe 80 (middle-early), Krestyanka and Rossiyanka (medium-maturing). Correlation dependence of protein and essential amino acids content between the sum of active temperatures and precipitation was revealed. Meteorological conditions of the experimental years can be characterized as unfavorable, arid, with uneven distribution of precipitation (HTC 0.52–0.54). A positive strong relationship was observed between the sum of active temperatures and protein content (r = 0.74-0.98, d = 60.8-96.0 %) in the phase of sprouting – full ripeness depending on the variety. The correlation of precipitation with protein content showed a strong negative relationship on all the varieties (r = –0,70 … –0.99, d = 49,0–96,0 %). Increased temperature regime and precipitation deficit contributed to the increase in the percentage of protein content in millet groats of the studied varieties. Lower temperatures and increased precipitation cause a decrease in protein accumulation. The first deficient limiting amino acid, by which the biological value of protein is estimated, is lysine with the highest value of 20.75 % in the variety Povolzhskoe 80. The increase in lysine content in all the studied varieties is significantly influenced by the temperature regime in July in the phase of tillering – ear formation (r = 0,73–0,99).

   The article presents the results of a new preparation test – natural plant complex (NPC) "White Pearl Universal Antifreeze" (WPU Antifreeze).

   The purpose of the research was to study the effect of organomineral fertilizer on physiological and biochemical indicators of apple tree resistance to spring frosts.

   The object of research is apple trees of the Sinap Orlovsky variety from the bioresource collection of the Russian Research Institute of Fruit Crop Breeding. The experiment was laid in three variants: 1 – control (no treatment); 2 – foliar treatment with 1 % solution of the NPC "WPU Antifreeze"; 3 – foliar treatment with 3% solution of the NPC "WPU Antifreeze". There are three replications, with five record trees in each variant. Two-year studies revealed that three-fold treatment with 1 and 3 % solutions of the NPC "WPU Antifreeze" preparation increased the level of bound water in the fruit buds by 9.8 and 3.8 % against the background of sucrose increase by 32.3 % compared to the control, which presumably protects plant cells from freezing during spring frosts. At the same time, it is shown that treatment with the NPC "WPU Antifreeze" preparation probably promoted acceleration of proline biosynthesis and transport into the budding fruit buds. After threefold treatment with 1 and 3 % solutions of the drug, the level of proline decreased 8.0 and 9.2 times, respectively, in the control by 7.8 times. In addition, the positive effect of the preparation NPC "WPU Antifreeze" on the stability of flowers and buds of apple trees both in laboratory and field conditions was noted. Thus, the application of the preparation NPC "WPU Antifreeze" allows increasing plant resistance to low-temperature stress in spring due to optimization of the water regime and improvement of carbohydrate-protein metabolism.

   Barley net blotch is a widespread disease of cereal crops worldwide, causing significant economic losses. The predominant method of controlling it remains chemical defense, which has many negative consequences. It should be noted that the causative agent of the disease, the fungus Pyrenophora teres, belongs to the class of the pathogens with a high probability of developing multiple resistance to several chemical fungicides at once. In this regard, the protective effect of Bacillus velezensis strains BZR 336 g and BZR 517, as well as Pseudomonas chlororaphis BZR 245 F on two varieties of winter barley with different resistance to the causative agent of net blotch in two-year field trials was investigated. It was found that treatment with the above strains reduced the development of net blotch on average by 26–30% in the conditions of the central zone of the Krasnodar Territory. In 2022, the strains were able to compete in efficiency with the chemical reference. It was found that the reduction of disease development was more pronounced on the susceptible variety Romance when treated with the strains, with an average of 25.7–38.8 % compared to 20.9–25.3 % on the resistant variety Iosif. It was determined that treatment with liquid strain cultures before sowing and during the growing season is more effective than other methods. In 2018, seed and plant treatment with the strains was more effective than other methods: on the variety Iosif by an average of 6–8 % and on the variety Romance by 8–24 %. In 2022, seed and plant treatments with the strains were on average 12–17 (Iosif) and 35–38 % (Romance) more effective than other methods of treatment. The biological efficacy of the strains depended on climatic factors. In favorable weather conditions, the maximum reduction of disease development was observed with the use of strain of the Pseudomonas genus, in conditions of unstable meteorological background the greatest efficiency was demonstrated by bioagents of the Bacillus genus. The results of research have shown that biological methods of controlling winter barley net blotch are quite effective and require further implementation. Biological means of plant protection in addition to suppressing the harmfulness of phytopathogens will contribute to the production of environmentally safe products in conjunction with the reduction of pesticide pressure on agrocenoses.

   One of the important aspects that guarantee product safety is constant sanitary and microbiological control at all stages of production. This study presents an analysis of monitoring investigations aimed at determining the spectrum of common species of coagulase-negative staphylococci in the bulk milk at four mastitis-unfavorable dairy farms in the Moscow region during one year. It was found that Staphylococcus epidermidis was detected more frequently than other species (42.9 % of the number of the isolated coagulase-negative staphylocococci), St. saprophyticus and St. simulans were detected less frequently (14.3 % each), St. haemolyticus, St. chromogenes, St. lentus and St. hominis were registered even less frequently (7.1 % each). It was determined that up to 28.0 % of bacteria of the genus Staphylococcus were isolated in the bulk milk in autumn on all the farms. The ratio of St. aureus and coagulase-negative staphylococci in the bulk milk on the farms of the Moscow region in the autumn period is presented. Identification of coagulase-negative staphylococci isolated during the autumn lactation period has been performed. In the bulk milk, St. saprophyticus and St. epidermidis were detected more frequently (23.1 % each), St. simulans and St. chromogenes were detected in 15.4 % of the cases, and St. hominis, St. haemolyticus, and St. lentus were detected somewhat less frequently (7.7% each). Average data on Staphylococcus aureus indication obtained for 2023 in different farms of the Moscow region from the bulk milk have been analyzed. Staphylococci levels in the bulk milk were highest in spring (38.1 %), summer and autumn data were approximately the same (25.3–28.0 %). The lowest level of staphylococci in the bulk milk was observed in winter (18.5 %).

   The analysis of the epizootic situation on bovine leukosis in the Omsk region from 2018 to 2022 was carried out on the basis of the received data on the results of diagnostic tests in the immune diffusion reaction (IDR) and the hematological method. Despite the widespread viral infection, there was a slight downward trend in the number of positive samples from 16.8% in 2018 to 14% in 2022, nevertheless, the seroprevalence rate exceeded 5% in the predominant part of the region. The percentage of animals with leukosis during this period, on the contrary, increased 1.5 times. Several modifications of artificial neural networks (ANN) with nonlinear dependence on the Wolf numbers (W), harmonics of the Fourier spectral model, as well as the additionally introduced factor “Sigma”, which takes the value of 1 at W ≥ 110 at the input, were created at the next stage of the research in order to predict the further development of the epizootic situation in bovine leukosis. Three approaches of the ANN research were used: with spectral analysis from the beginning of the known period (from 1994); with spectral analysis from the end of the known period (from 2022); with construction of the ANN from the 1st to the 9th layers with odd-numbered acceleration. A total of 9 packages including more than 40 neural networks were created. The research was carried out in the direction of increasing the number of layers of the neural network and changing the harmonic composition. In some ANNs, a significant variation in the expected number of bovine leukosis virus infections was observed when the number of the layers was increased. In others, on the contrary, the forecast spread was minimal. Application of these approaches makes it possible to consider different scenarios of epizootic situation development in bovine leukosis and to choose the most optimal models when new data on the spread of infection become available.

   Vaccines are well-known and the most cost-effective strategy for preventing and suppressing global infections. New manufacturing platforms are being developed for safe, rapid and large-scale production, the implementation of which can eliminate the inherent drawbacks of traditional production. Furthermore, new vaccine stabilization and delivery systems are being developed to overcome dependence on the "cold chain".

   The objective of this review is to compare the traditional and most widely used egg-based platform with a potential biotechnological platform based on silkworm (Bombyx mori) as an alternative platform.

   From a public health perspective, influenza remains the only human disease that requires annual vaccination. For this reason, the presented review largely reflects the peculiarities of this direction. A comprehensive comparative assessment of key manufacturing indicators at the stages of USP and DSP, reflecting their effectiveness, showed a significant advantage of mulberry silkworm-based biotechnological solutions over egg-based platform. The possibility of effectively using the obtained raw materials, both primary (cocoon shell from which biomaterials are obtained for stabilization and vaccine delivery after processing), and secondary, mulberry silkworm pupa which serves as a bioreactor for the production of the target protein (hemagglutinin, HA) shows the advantages of the mulberry silkworm-based platform and in terms of raw material versatility compared to the chicken egg-based platform, and relative to another alternative production platform developed based on cabbage looper (Trichoplusia ni) biotechnology.

   The results of research on new feeding products for farm animals are presented. Due to the reduction of fish meal production in Russia, as well as the unstable quality of commercial fish meal of animal origin, which is traditionally used as a source of complete protein, metabolizable energy and macronutrients in the diet of poultry, pigs, aquaculture, the issue of searching for alternative feed ingredients has become relevant. The possibility of replacing fish and meat and bone meal with meal from industrially cultured insects has been studied. The biochemical composition of feed meal from insects of different orders (Diptera, Orthoptera, Coleoptera, Blattodea) promising for industrial cultivation has been studied. Due to the high content of crude fat and crude protein, the metabolizable energy in this product, determined for poultry and pigs, had higher values (16.4–21.60 MJ/kg) than in the studied samples of commercial fish and meat and bone meal of domestic producers (13.7–18.73 MJ/kg). The crude protein content of insect meal from different insect orders had the values ranging from 45 to 87 %, with the proportion of pepsin digestible protein ranging from 59.2–87.6 %. The absolute amount of pepsin digestible protein in defatted meal from the insect species studied was 45.8–61.0 g/100 g and was comparable to the values obtained for defatted fish meal (43.9–72 g/100 g) and meat and bone meal (34.8–68.3) from different producers. At the same time, the content of macronutrients (calcium and phosphorus) of the product was significantly inferior to fish and meat and bone meal. Also, insect meal had a significant amount of chitin (4.1–7.2 %), which may have a significant impact on the feed value of the product.

   The peculiarities of bovine leukosis virus (BLV) manifestation on the territory of the Republic of Tuva for 1974–2023 have been revealed. Epizootologic indicators of the disease status, epizootic index and nidus index have been established. During the whole period of observation leukosis has not been registered on the territory of 7 highland and remote districts. One of the features of the well-being of highland and remote areas are natural and geographical conditions (isolated location surrounded by mountains occupying 80 % of the region's territory, limited connections with other regions, difficult accessibility). Another peculiarity is free range animal husbandry, mainly indigenous cattle on fodder, with frequent changes of pastures and free keeping of cattle. With the expansion of economic ties, importation of pedigree dairy cattle from the neighboring regions (which, according to the results of the studies, are unfavorable in terms of bovine leukosis), the epizootic situation became unfavorable. This is the main feature of the region's leukosis adversity. Leukosis registered mainly in the central districts located in the flat territories of intermountain basins, where there are favorable conditions for maintenance and feeding of dairy cattle. Under joint conditions of keeping and exploitation there is a risk of infection of other animals, which is also a feature of leukosis on the territory of the Republic of Tuva. Bovine leukosis was first registered in the Ulug-Khemsky district at a dairy farm in 1977 in a cow of the Holstein Friesian breed. Out of 50 years of observation, 11 leukosis-affected districts (Tandynsky, Pii-Khemsky, Kaa-Khemsky, Chedi-Kholsky, Ulug-Khemsky, etc.), totaling 60 leukosis-affected points, have been registered in the republic for 29 years. 914,638 animals were examined, 845 animals were found to be positive, or 0.09 % of the total number of the livestock examined in the country, the disease status was noted in 40.8 %, the epizootic index (EI) for 50 years of observation amounted to 1.2 units, the nidus index (NI) – 14.08 seropositive animals per 1 unfavorable location. Sporadic and isolated cases on the territory of the remaining 6 unfavorable districts (Barun-Khemchiksky, Sut-Kholsky, Kyzyl, Kyzyl city, Tes-Khemsky, Tojinsky) are also associated with the importation of breeding cattle, where with the implementation of diagnostic and other anti-epizootic measures, the situation, without epizootic and geographical development, rapidly improved. The Republic of Tuva has been free from bovine leukosis since 2022.

   Symptoms of garden strawberry leaf spot disease caused by phytopathogenic fungi are described. The impossibility of their identification by visible signs in the initial stage of the lesion is shown. Early diagnosis is possible using antibody-based methods with phytopathogen antigens, molecular assays and aptamer-based methods. However, there are a number of difficulties in using them. To create a portable means of early diagnosis, methods based on the detection of electrical changes in plant leaf tissues as a result of fungal pathogen attack have been proposed: the method of electrical impedance spectroscopy and the method of electrical equivalent circuits. The methods allow determining a diagnostic parameter, the condenser capacitance modeling the capacitance of leaf plant cell membranes. It has been found that condenser capacitance values decrease as the degree of strawberry leaf lesion increases. The proposed methods are realized in a device consisting of an electrode system, electronic and computing units. In the electrode system, non-polarizing electrodes are located on both sides of the garden strawberry leaf. The electronic unit is designed to record the plant tissue impedance. The computing unit (laptop) searches for the frequency at which the reactive component of the impedance is maximum and calculates the diagnostic parameter from these data. The device operates under the control of a program for recording the reactive component of plant tissue impedance and a program for determining the diagnostic parameter. To evaluate the accuracy of the device, the values of the diagnostic parameter obtained by the developed device and the precision impedance analyzer WK 6505B were compared. The values of the parameter were 1594 and 1574 pF, respectively.

   The influence of organic matter of sod-podzolic medium loamy soil on the yield and quality of flax products was studied by means of vegetation and field experiment. The research was conducted in 2021-2023 in the north-eastern part of the Republic of Belarus. The soil was characterized by organic matter content of 1.51–1.52 – 2.02–2.05 – 2.52–2.56 %, high content of mobile forms of phosphorus (242–250 mg/kg soil) and potassium (216–232), medium content of boron (0.56–0.62) and copper (2.7–2.9), and low content of zinc (2.5–2.9 mg/kg soil) with an acidity of 5.4–5.5 pHac1. The studies were conducted under drought conditions of fiber flax vegetation in 2021 (Selyaninov HTC 0.74), under slightly drought conditions in 2022 (HTC 1.24) and extreme conditions in 2023 (HTC May – 0.08, June – 0.68, July – 3.71, vegetation period – 1.63). The positive influence of soil organic matter on the yield and quality of flax products has been proved. Increasing the organic matter content in the soil from 1.5 to 2.0 –2.5 % improved seed yield by 16–35 % due to an increase in bolls (+22–39 %) and seeds per plant (+46–65 %), flax straw – by 10–33 % due to an increase in technical stem length (+6–13 %), fiber – by 14–37 %, including long fiber – by 15–43 % by increasing the number and size of bast bundles (+5 – 20 and 5 –28 %), as well as the number of elementary fibers in the bundle (+10 –15 %) and their transverse size (+7 –10 %). The quality of retted flax straw was improved by 1–2 numbers by increasing its content of long fiber fraction by 7–11 % rd. and improving color uniformity by 16–21 %. The increase in quality of long flax rolled and beaten tow by 1 number is due to an increase in its strick of flax length (+8–13 %) and strength (+3–8 %).