The working bodies of screw volumetric machines are complex-profile cycloidal screw surfaces. This article deals with the problem of technological preparation for the production of such surfaces, associated with the uncertainty of the technological capabilities of a special processing strategy. To solve this problem, an analytical expression of the criterion was proposed, which makes it possible to assess the applicability of the processing strategy for the given geometric parameters. The adequacy of the proposed criterion is confirmed by machine and natural experiments.

Currently, there are practically no mechanization tools on the market that combine grass removal (mowing) and the levelling loosening of the upper soil layer, while cutting the root systems contained in the soil in one pass. The purpose of the study was to provide a theoretical rationale of the modifi ed design of the working tool of the combined rotary mower, as well as to conduct its laboratory and fi eld studies. Complex theoretical, laboratory and fi eld studies were carried out using the equipment of the Department of Technological and Transport Machines and Complexes, the Department of Technology of Processing and Storage of Agricultural Products of Tver State Agricultural Academy and recognized methods of experimental research. In the course of theoretical studies, the main parameters of the new working tool were determined, which enabled two technological processes to be carried out in one pass: grass mowing and cutting with loosening of the top soil layer (0…10 cm). On the basis of the obtained data, a workable model of the working tool was designed. When tested in laboratory conditions, regardless of the operating modes and the initial state of the cultivated soil, improved agrophysical properties were observed in terms of absolute humidity and saturation with root residues. It was found that the most optimal level of absolute humidity for the impact of the working tool on soils of light-loamy granulometric composition was 20%, while the best structural and density indicators were observed at all values of soil saturation with root residues; thgey averaged 2.24 units and 1.26 g/cm3. It has been established that at low operating speeds, it is advisable to use a higher rotation speed of the working tool (at 150 rpm), at the same time, with an increase in speed, the speed of rotation should be reduced (to 110 rpm). As a result of fi eld experiments, convincing data were obtained on the feasibility of using a new working tool that provides eff ective mowing of grassland vegetation (the purity of the stem cut is 95.6%) and loosening of the surface layer of the soil (0…10 cm), increasing the structural coeffi cient by 26.8% while optimizing the density and grinding of root systems. The next stages of the study include developing and manufacturing a workable design of a combined rotary mower prototype that ensures the optimal energy intensity of performance and the required quality of technological processes.

The research aim was to study the peculiarities of the formation of productivity of current varieties of oats of domestic selection (Argamak, Krechet, Yakov) when grown on different backgrounds of mineral nutrition (1-natural fertility (without fertilizers), 2 – N16P16K16 when sown +N45 in the feeding (tillering phase), 3 – N16P16K16 during sowing +N90 in feeding) and foliar treatments in the tillering phase with humic preparation Humate+7; give recommendations to the production based on the results obtained. Comprehensive research was conducted in 2018–2020 on the fields of the Educational Scientific and Innovative Production Center “Agrotechnopark” of the Tver State Agricultural Academy. Field and laboratory researches of photosynthetic activity indicators, crop structure, yield accounting, grain quality, mathematical processing of the results were carried out according to well-tested methods in agriculture. It was found that the greatest responsiveness to the applied fertilizers was distinguished by seed oats of the Yakov variety. The crops of this variety were obtained with foliar treatment at the tillering stage with a 1% working solution of Humate+7 against the background of application of N16P16K16 at sowing and N90 in feeding grain yield. It is equal to 4.77 t/ha with the greatest grain in the experience – 559 g/l (which corresponds to the grain of the 1st class), and the lowest filminess is 23.4%. These features of the fertilizer system had a positive effect on the crops of all the studied varieties of oats. That allows us to recommend their production as the most promising. At the same time, it is worth noting that non-root feeding with Humate+7 is effective both in conditions of reducing doses of mineral fertilizers and in their complete absence, increasing grain yield by an average of 27.0%–31.5%. The increase in crop productivity is associated with an increase in the photosynthetic activity of plants in crops and an improvement in the main parameters of the crop structure (the density of the productive stem, the weight of grain from the panicle).