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The authors have conducted studies to determine the traction efforts of the digging share of a machine for harvesting root crops and onions based on its technological parameters - speed and digging depth. The paper presents a design scheme and general view of the offered laboratory installation for determining the supply of a heap of onion sets to the digging share. The paper descries a methodology for conducting traction studies of the digging share of an onion harvesting machine and describes the operating principle of the digging tool of a harvesting machine, which ensures high-quality harvesting of root crops and onions with minimal energy consumption. As a result of the studies, the response function values of the digging share’s tractive effort have been obtained taking into account the varying speed and digging depth. When processing the results of a two-factor experiment, a first-order regression equation was obtained to describe the relationship between the traction resistance of the digging share of a machine for harvesting root crops and onions and its technological parameters RП = f(vП, h), and the main statistical characteristics of the experiment. It has been established that in order to ensure the quality of bulb extraction from the soil (minimal damage and loss of bulbs) as well as high performance of the harvesting machine, the digging share speed should amount to 0.8...1.2 m/s and the digging depth should equal 3...5 cm.

The paper presents the results of laboratory tests of the wear of soil tillage blades. The authors have developed an experimental unit with a linear-moving sample blade when interacting with an abrasive medium imitating the real soil. Physical properties of the abrasive medium can be changed by incorporating into the composition quartz particles, paraffin, ceresin, pulverized cement and other materials. The installation reproduces the operation of a blade shearing off soil particles of a loamy soil. The authors have obtained relationships between the inclination angle, the blade wear land width and length and the cutting path. As the depth of cutting increases, the wear rate increases in a parabolic manner. Due to the wavy irregularities of the furrow bottom, the wear rate decreases by 10...15%. It is caused by a load decrease of treated abrasive medium regardless of the blade material (steel or aluminum alloy). With the hardness of medium increases to more than 2 MPa, the blade wear rate increases, but the wear land angle to the furrow bottom decreases due to a changed wear mechanism. As fine dust particles concentration in abrasive medium increases, a facet formed on the blade edge contributes to its rapid blunting. As the cutting speed increases from 0.3 to 0.6 m/s, the blade wear rate increases by 25...30% due to raising soil resistance and the specific energy spent on soil deformation and destruction.

Positioning of a land cultivation unit on the fi eld determined by the specifi c location of its working tools is one of the precision farming criteria used in the cultivation of row crops. The navigation system provides reference-input signals as it determines the position of the machine-tractor unit (MTU) and its implements. When the MTU moves along the treated fi eld surface, its tools deviate from their trajectory due to the difference in density and soil moisture, as well as local inclines. The authors present a controlled mounted implement UNU-2, which together with the navigation system installed on the tractor allows determining the location and course position relative to the coordinates specifi ed by the navigation system. The paper also presents characteristics and operating principle of the device. Using the controllable mounted implement will allow positioning and changing the inclination angle of the tool on the prescribed fl at horizontal surface. This will ensure high accuracy of operations performed by the MTU, increase its technical performance level, and reduce labor costs. Thus, the use of tractors and controllable mounted implement based on navigation systems ensures the accuracy and effi ciency of such technological operations as planting and cultivatingof row crops. The development of a technical device for adjusting the trajectory of mounted implements increases the effi ciency of the MTU operation.

Today, post-harvest processing of breeding material requires using a screen seed cleaner that should be adequate in performance and comply with all the requirements for plant-breeding machines. For the research, use was made of a model bench of a screen seed cleaner with pre-determined kinematic parameters of the scree shoe and the inclination angles of screens. The experiments were conducted for five variants of the vibration amplitude of a screen shoe (7, 10, 14, 18 and 22 mm), with a change in the frequency of its vibration frequency from 169 to 470 min‑1. At the same time, the kinematic screen index varied within 6.9…19.3 m/sec2. The same experiments were carried out at two inclination angles of the screen shoe –6 and 9°. It has been shown that an increase in the kinematic indicator of screens leads to decreased clogging of screen holes. The optimal values of the kinematic indicator of screens with oblong holes, depending on the vibration amplitude, are within 11.0…15.0 m/sec2. The extraction coefficient of minor impurities in this case varies within 84.6…89.6%. With a large inclination angle of the screens (9°), the penetration rate of the upper screen (with round holes) is 3…10 times higher, and the lower screen (with rectangular holes) is clogged approximately 2 times more intensively than at an inclination angle of 6°. The authors have determined that for a screen seed cleaner to operate at the modes ensuring optimal processing of both small seeds and grain crops, the vibration amplitude of a screen shoe should equal 9 mm, and its vibration frequency shouldrange between 350 and 450 min‑1 at an inclination angle of screens amounting to 7°.

The paper presents some application fi elds and examples of applying electrotechnology in agricultural production as exemplifi ed by the use of electric, magnetic and electromagnetic fi elds. The authors determined promising research areas concerning the application of electrotechnology in gardening: the use of magnetized water for watering tree crops and bushes; the use of a strong electric fi eld of high voltage to produce a fi ne electroaerosol in the form of fog or cloud of electrically charged solution droplets (chemical preparation to combat diseases and pests of garden crops) to increase the preparation effi ciency (from25 to 75%) and reduce the environmental impact. The paper presents the designs of technical devices for obtaining magnetized water. The authors offer an original magnetic fi eld source consisting of an inductor with windings and a ferrite core and having additional features for regulating the rotation speed of the magnetic fi eld, and the formation of magnetic fi elds with different harmonic composition, depending on the shape of the output voltage of a transistor frequency converter. The paper also provides a description of an electric circuit (powered by a battery or a low-power rectifi er) of a small-sized source of a strong electric fi eld using high-frequency transformers, the mass and size of which are reduced twice at such frequencies.

The paper studies a rotary tiller having a horizontal rotation axis of working tools, which allows to improve the quality of soil tillage as compared with passive working elements. The authors have calculated the power required for soil tillage with a rotary tiller КФГ-3.6 and determined the relationship between the power and the rotary tiller parameters: the body movement speed, the peripheral speed of a knife blade point, the depth of soil tillage, the knife feed, and the cutting arc length. Using the methods of step-by-step regression analysis, the authors determined a regression equation that adequately approximates the relationship between power per unit operating width and the studied parameters. The multiple correlation coeffi cient of the regression equation with the movement speed factors of the rotary tiller frame, the length of the cutting arc, the knife feed equals 0.95. It has been established that for calculating the specifi c power required for rotary tillage, with a given number of knives on the rotary tiller circumference, three parameters need to be taken into account: the movement speed of the cutter frame, the cutting arc length, and the knife feed. The signifi cant effect on the specifi c power of the cutting arc length is explained by the fact that, along with soil cutting with a blade, power requirements are also affected by soil crushing and wedging with the knife.

The most promising of the previously known approaches in the use of theories in the practice of water supply of plants is the approach based on the bioenergy theory of productivity. The paper contains a brief review of conventional approaches to the use of theories and discoveries in the practice of water supply of plants and methods of its evaluation. It is proposed to estimate the need of plants for water by the amount that should be spent on transpiration to reduce the plant leaf temperature to the optimum temperature for photosynthesis by evaporative cooling. It is shown that optical radiation, along with photosynthetic radiation, has other effects on plants (thermal, photoperiodic, photomorphogenic, etc.). The authors suggest identifying the transferability of indicators (criteria) describing the basic conditions of the external environment on thermodynamic basis. Thus, the research purpose is to justify the analytical dependence to take into account the influence of these factors on the water supply of plants. With the help of experimental measurements and calculations of evaporated water, two samples of water lost in evaporative cooling are obtained, which have the same characteristics. On the basis of the carried out researches, the analytical dependence of evaporated water at constant illumination is obtained in the form of a polynomial of the second degree. It is shown that when lighting is switched on, the evaporated water first decreases, and then the phase of active photosynthesis occurs, and the amount of evaporated water grows. It has been found that taking account of bioenergetic aspects, the plant should be provided with water at an average rate of 0.7 g/h, and with the onset of the active phase of photosynthesis, an hourly amendment should be made according to the obtained dependence.