The sound practice of keeping meadows and pastures, including the simultaneous use of long-term fallow lands in the crop rotation pattern, is possible only through improving the existing agrotechnical methods, sowing being the least energy-intensive among them. The study goal was to assess the uneven seeding of small-seeded crops using the technical modernization of a seeder equipped with mechanical seeding units and an innovative coulter group that ensures high-quality sowing. Comprehensive studies of the problems under consideration were carried out at Tver State Agricultural Academy. The authors present a systematic approach for assessing and implementing the technological process of sowing multi-species agrophytocenosis of small-seeded crops. The method includes the following stages: studying the profile of the soil layer necessary for even germination of seeds; analyzing the parameters of placing the seed material, taking into account the depth of planting, the inter-row spacing width, the width between the seeds in the rows and determining the modeled level of plant density; assessing the possibility of modernization and use of the grain-fertilizer seeder SZ-3.6 for the simultaneous sowing of seeds of two crops; designing and testing a combination opener for simultaneous strip sowing of two different crops. The data obtained aim to expand the theoretical and practical grounds for the development of new seeding machines and their working elements and introduce highly productive multicomponent agrophytocenoses for forage production. The following stages of research will optimize the methodology for studying the seeding parameters of agricultural plants to reduce the labor intensity and conduct field tests of the sowing section using various types of small-seeded crops.

One of the convective drying methods used to intensify the process of drying granular materials is the use of a device with a fluidized bed. The essential advantages of fluidized bed dryers are the uniform drying of all the particles in the bed and the ease of loading and unloading the material. The study goal was to conduct an experimental study of the hydrodynamics of the fluidized bed of millet and pea seeds and the determination of the first critical velocity (the rate of the beginning of fluidization) based on these data. The authors took small (millet) and large (pea) seeds for the experiment. Based on the experimental data obtained, they constructed pseudo-liquefaction curves - AP = f (v) for millet and peas to determine the first critical fluidization rates (0.73 m/s for millet and 1.68 m/s for peas). The experimentally found values of the first critical fluidization rate were compared with the values calculated by the equations of O.M. Todes, Wen and Yu, and Grace. The study showed that all the equations provide an acceptable accuracy of calculations, but the accuracy of using the equation of O.M. Todes is somewhat higher. Therefore it can be primarily recommended for engineering analysis. The first critical fluidization rates, calculated according to the formula of O.M. Todes, were, accordingly: 0.69 m/s for millet and 1.60 m/s for pea. The calculation and experimental data on the first critical fluidization rates for millet and peas agree satisfactorily (the relative error for millet is 5.5%, for peas - 4.8%). The sufficiently high accuracy of the first critical fluidization rates is explained by the correct geometric shape of the studied seeds, which is close to spherical. Therefore, the first critical fluidization speed of the studied seed material can be determined using the formula of O.M. Todes.

When tilling the soil with a vertical-rotary limiter of the raspberry row width, rotating knives perform its transverse transferring. In this regard, it is advisable to find the means to control the process. The study revealed the influence of the design parameters of the raspberry row width limiter on the pattern and degree of the lateral displacement of the cross-section of the cultivated soil strip. The authors assessed the intensity of the process of transverse soil redistribution by comparing the positions of the gravity centers of the treated strip cross-section before and after the tillage operation. The studies analyzed medium and heavy loams with a humus content of less than 2.5% and a wide range of variation in moisture content and contamination of the treated strip. With a rotor diameter of about 900 mm, the lateral displacement of the gravity center of the strip cross-section varies within the range of 50...100 mm. The authors found that the lateral displacement control of the soil layer is possible at a constant forward inclination angle of the rotation axis of the knife rotor, which is equal to 18°. This can be done by changing the lateral inclination angle of the specified axis towards the row spacing center in the range between 10 and 20°. As a result, a significant portion of the discarded soil returns to the treated strip surface, minimizing its outside throw-off and eliminating the possibility of injuring the raspberry shoots. The limiter proposed by the authors has a longitudinal baffle installed at an angle to the vertical with a minimum energy intensity of the process. It helps to maintain the cross-section of the surface of the row spacing of raspberries in a leveled state throughout the entire life of the plantation.

During the heating period, the supply air temperature is lower than that in industrial premises, and the cooled air is denser. Entering a warm room, it tends to move downward. This condition leads to the formation of chilled and stagnant zones. The article presents a theoretical study on the possibility of ensuring the maximum propagation range of a non-isothermal supply air jet by angular correction of the flow vector at the outlet of the ventilation unit. Based on the theory of free air distribution, the author analyzed and graphically visualized the flow trajectories of the supply air from the combined climate control unit with heat recovery in the production room in the range of outdoor temperatures from +10 to -40°C. Given the time period of outdoor temperatures, flat sections of a three-dimensional graph were built with a step of 10°C in the range from +10 to -30°C. The author found that the maximum service area of the installation is limited by the propagation range of the supply air jet. The area can be increased by changing the direction of the flow vector by an angle ranging between 0 and 34°. The value of the inclination angle of the flow vector of the supply air jet is determined by the obtained approximation dependency. Considering the regulation of the flow vector, the author used the formula of M.Z. Pechatnikov to determine the propagation range of a limited axisymmetric jet. The studies carried out made it possible to establish the relationship between the propagation range of the supply air jet of the installation and the outside temperature, the inclination angle of the flow vector, and the theoretical variation range of the inclination angle of the flow vector, ranging between 0 and 34°.

Industrial production of microalgae phytomass from agricultural waste for energy production purposes can solve the internal energy supply and environmental issues in the farm sector. The closed-cycle energy supply scheme is used in the livestock breeding facility to get hot water, feed additives to the cattle diet, biohumus, motor biofuels, and carbon dioxide, which is advisable to use in microalgae cultivation. The article presents a study of the experimental process of microalgae cultivation in a photobioreactor. The study goal was to determine the influence of technological conditions on the productivity of microalgae and obtain initial data for the development of closed cycles of using the energy potential of algamass in the heat and power supply of farm enterprises (e.g. dairy and poultry farms etc.). The authors carried out experiments using a photobioreactor for microalgae cultivation with an intelligent control system. The developed photobioreactor differs from the conventional variants by the pulsating hydrodynamic mode of feeding the nutrient solution. This modification increases the productivity of microalgae cultivation by up to 15%. The cultivation conditions of Chlorella vulgaris microalgae on combined nutrition showed a noticeable increase in crop productivity when adding cattle manure extract in the amount of 30 to 60% (vol.) to the nutrient medium. This factor can be used to design closed cycles of thermal and electrical supply of cattle farms based on third-generation biofuels obtained from microalgae phytomass.

Efficient performance of agricultural operations requires the active use of reclamation systems, e.g., bypass canals. One of the main factors that reduce the quality of reclamation is the accuracy of positioning the soil profile when cleaning or arranging canals. Excavating equipment is used to develop reclamation canals. Modernization of excavators by introducing automatic leveling systems (ALS) into their design can increase performance, accuracy, and, therefore, productivity. The authors consider three principal solutions of the ALS design during the operation of excavators: ALS2D control system, ALS satellite control system, ALS AUTO satellite leveling system. Field tests were carried out at the test site to check the quality of the embankment erection with a JCB JS205 excavator with the ALS. The data obtained were compared with the indicators of blading with a JCB JS205 excavator without the ALS. The research results showed that the most advanced option was the ALS AUTO satellite leveling system since the quality of the work performed practically does not depend on the human factor. Also, the excavator with the ALS AUTO satellite leveling system proved to have a lower deviation angle of the developed embankment from the design-specified angle per 1 sq. (2.4%) as contrasted to the ALS2D control system (8.3%) and the ALS satellite monitoring system (6%). The excavator without the ALS demonstrated a value of 11.1%. Therefore, it is advisable to modernize excavators by introducing the automatic leveling system, which will increase the performance by 200% and double the accuracy of the work performed.

One of the most common connection types in mechanical engineering and construction is the shaft-hole connection. The mechanical stresses caused by its loading are distributed in the contact zone of the loaded parts of the joint. In some cases, they can lead to destruction. Therefore, while designing, it is important to analyze the mechanical stresses in the contact zone. Traditionally, calculations assume that the contact stresses are distributed according to the cosine law. However, this is not entirely true, especially with different shaft and hole diameters. The authors examined theoretical studies of the contact zone of the shaft and the hole (including the cases of different diameters) and the stress distribution in the contact zone. Based on the studies, they performed numerical calculations in the APMWinMachine environment to determine the stresses in the volume of the shaft and the plate with a hole when loading the shaft-hole connection. The analyses were performed for the two-dimensional case by the finite element method in the APMStructure program. The results show that when the diameters in the connection are equal, the stress distribution is close to the cosine law. In this case, only one stress raiser occurs in the contact zone, which is located on the line of action of the loading force. However, if there is a slight discrepancy in the shaft and hole diameters, there are three stress raisers in which the connection may break - the central zone and two side zones. The angular distance between them can be determined based on the known theoretical formulas. The authors made an experiment with a plexiglass model, which qualitatively confirmed the correctness of the analysis performed.

In agriculture, the downsizing of the machinery fleet is still underway, which leads to a violation of the agrotechnical terms of technical operations, incomplete yields, and loss of products. Reproduction of the machine and tractor fleet in agriculture is possible provided there are financial sources: own (depreciation, profit) or borrowed funds. Based on the analysis of statistical data of Rosstat, the Ministry of Agriculture of Russia, publications in scientific journals, etc. the author established that the share of investments in machinery and equipment in the total volume of investments in fixed assets in agriculture in 2017-2019 was 30% less than in the Russian economy as a whole. In the structure of investment financing, the share of own funds was more than 50%, including the depreciation share of about 20%, which indicates that the reproduction mechanism does not work effectively enough. The volume of profit is also insufficient. In 2019, the share of enterprises with a profitability rate of more than 10% (making the reproduction process feasible) amounted to 55%. The high debt on loans (about 7% of the total revenue of agricultural organizations, 136% of the profit in 2019) makes it necessary to provide state support for the acquisition and search for ways to operate the reproduction mechanism more effectively.

The accelerated pace of technical and technological innovations, robotization and digitalization contribute to the development and transformation of agricultural machinery and equipment. Digital services introduced in the agribusiness sector make it possible to increase the efficiency of sectoral management, the rate of capital turnover, the efficiency of resource use, the transparency of state support provision, and reduce the costs of agricultural producers necessary for reporting the financial outcomes of their activity. The use of modern digital technologies makes it possible to increase the efficiency of sowing and harvesting operations, vectorize the crop area, as well as accurately and quickly determine the vegetation index. The use of the precision farming technology contributes to the minimization of uncertainty factors, ensures the planning and rational use of production processes, and leads to an increase in labor productivity and quality. Automated setting up of agricultural machinery helps maximize its productivity, eliminating the need for constant manual adjustments, and reducing the workload on the operator. Despite the intensive introduction of digital technologies in agriculture, due to the specific features of the industry, it is not possible to ensure completely remote digital farm production. Poor coverage of rural areas with the Internet network, the lack of free funds for small and medium-size businesses to purchase equipment and technologies, as well as the lack of highly qualified personnel hamper the full use of new digital solutions. Analysis of digital transformations in agriculture has shown that the speed and scale of ongoing transformations lead to the development of certain imbalances in the sector. A negative consequence of the massive digitalization of production is the redundancy of labor resources, which has negative social effects. Further digitalization of the agribusiness sector must ensure a symbiosis between online technological solutions and the offline “field” work of specialists.

On-farm compound feed production from self-produced raw materials is favorable to agricultural enterprises under present-day conditions. The authors carried out a comparative technical and economic study of the conventional and modular small-scale on-farm compound feed plants with a capacity of 2 tons per hour, designed for agricultural enterprises with an average livestock population of 6.. .8 thousand pigs. The proposed modular plant consists of two modules - the operative storage of raw materials and the main module of grinding and mixing. Modules with installed equipment are delivered and placed on a light foundation, connected by transport equipment and with tanks for raw materials and finished products. The conventional factory is a technological line housed in a hangar and used for crushing, metering, and mixing raw materials. It consists of a separator, a hammer mill, weighing equipment, a mixer, containers for raw materials and finished products, transport, and aspiration equipment. The technical and economic analysis has shown that the erection and operation of the on-farm modular enterprise require 41% less capital investments than a traditional compound feed plant of the same capacity. The use of a small-scale modular plant will reduce operating costs by 23.8% (from 3094 to 2358 thousand rubles), increase the specific economic effect from the compound feed production by 1.6% (from 8.64 to 8.78 thousand rubles per ton) and return on margin by 4% (from 10.2 to 10.6%), reduce the payback period by 42% (from 0.8 to 0.46 years), and increase the net present value by 3% (from 66167 to 68216 thousand rubles), as compared to a conventional enterprise. The modular on-farm plants producing loose compound feed with a productivity of up to 3 tons per hour are profitable and economically sound as they can increase production efficiency of compound feeds for farm animals.'

The article is dedicated to Yuri Aleksandrovich Konkin, Full Member of the Russian Academy of Sciences, Doctor of Economics, Professor, Honored Worker of Sciences of the Russian Federation, Honorary Worker of Higher Education of Russia. After graduating with honors from the Faculty of Agricultural Mechanization of Moscow Institute of Agricultural Mechanization and Electrification (MIMESKH), Yu.A. Konkin came a long way from an assistant, associate professor, and professor of the Department of Farm Production Organization to Rector of Moscow Institute of Agricultural Engineering named after VP. Goryachkin - a leading university for the training of highly qualified engineering personnel. Yuri Konkin as an enthusiastic inborn organizer, a talented teacher, and a scientist, actively tried to improve the quality of teaching economic subjects while training agricultural engineering specialists. About 80 DSc and PhD theses have been defended under the supervision of Academician Yu.A. Konkin, the founder of the scientific school on the depreciation and service life of equipment, the restoration and renewal of the machinery fleet, the economics of agricultural machinery repair. Many of his students later became professors, key experts in the field of agricultural economics. The creative legacy of Yuri Konkin contains more than 200 scientific works and study manuals. His scientific and pedagogical activity was marked by seven government awards, including the Order of the Badge of Honor, four gold medals of the Exhibition of Economic Achievements, "For the Success Achieved in the Development of the National Economy of the USSR."

The origins of the scientific school of engineering and economics are inextricably linked with the development of agroeconomic science at MIMESH-MIISP-MSAU named after V.P. Goryachkin. The Department of the Production Management of Socialist Agricultural Enterprises, established in 1932, contributed much to the development of the scientific school of engineering and economics. The scientific school of engineering and economics has been accumulating research potential and experience in educational and methodological work. It has opened up new research areas in the economics of farm mechanization and electrification, contributing to the formation and improvement of educational and research structures. The worthy contribution to the establishment and development of the University's scientific school of engineering and economic was made by Nikolai S. Vlasov, Doctor of Economics, Professor, Honored Scientist of the RSFSR, and Professor Yuri Aleksandrovich Konkin, Academician of the Russian Academy of Sciences, Doctor of Economics, celebrating his 90th anniversary on October 21, 2021.