ECOLOGICALLY SAFE TECHNOLOGIES OF GRASS FEED PRODUCTION

The aim of the research was to find out the possibilities for reducing the prime cost of environmentally safe technologies fo the preparation of herbaceous fodder by improving technical means. During the recent years, on major individual and co? operative farms there is being introduced a perspective roll technology of processing wilted green grass with subsequent sealing of rolls m a flexible film. The advantages of the green grass processing technology with subsequent sealing of rolls in a flexible film are: - environmental safety o f the technology (exclusion of pollution with silo saps, absence o f odour nuisance, absence o f compounds m the feed that are detrimental to animals and formed during the common siloing, its low acidity); - considerably lower dependence of forage processing on weather conditions, complete mechanisation of engineering processes; - the forage can be processed in small quantities, and for its storage no specialised containers are needed, which is a valuable feature for small farms; - increased nutritive value and good gustative qualities providing a possibility of essential raising the yields of milk and its quality (retention of all nutrients and vitamins), insignificant losses of nutrients during the harvesting and storage period (not more than 10-15%)

ENVIROMENT-FRIENDLY FARMING PROJECTS IN LATGALE

By evaluating the strong and the weak points o f the Latgale region we can assert that its power lies in its natural resources which are luxurious in their mild modesty, with the best-preserved environmental originality in the north-eastern part o f Eutrope. The weak point of Latgale is the poverty of the population and disarrayed infrastructure. To eliminate the weakness, balanced education o f the population is needed, as well as profitable farming projects and support investments. A co-operation project was worked out by the Latvian Council o f Science “Optimisation o f the economic and social development of Latgale During four years “Foundations o f farming in Latgale ” have been developed. This report deals with what has been done; in monographs, available just here, the members of the conference can obtain detailed information

STUDY OF THE DISTRIBUTION OF AIR TEMPERATURE IN A GREENHOUSE HEATED BY AIR TO AIR HEAT PUMP

The temperature distribution inside the experimental greenhouse heated by air to air heat pumps and its impact on the growth and productivity of tomato plants were studied. Experimental greenhouse located at SIA Rītausma facility in South-East Latvia.Two commercially available regular air to air heat‑pumps with a combined heat power of 10 kW were used. To measure the temperature distribution, 18 temperature sensors with solar radiation shields at different heights and positions among the plants were installed. Additional 4 temperature sensors were used to measure the air flow temperature at the heating elements. Reference air temperature was measured at an industrial production facility heated by a common gas heating system.Temperature was found to be homogenous within 1 °C. Observed temperatures were up to 4 °C lower than set on the control unit of the heat pump. This discrepancy was compensated by higher set values for the controlling unit. As research showed the temperature stability was better than at the water-heated industrial facility at time slots when the sun was suddenly cleared from clouds.The cooling of the experimental greenhouse by air conditioning during summer time was rather challenging for the tomato plants and productivity. 23% of plant stems died until the end of the season and the yield was 50% lower than in the reference greenhouse. The energy efficiency compared to the industrial facility was approx. 8 times better and the estimated CO2 emissions were 8-16 times smaller compared to gas heating. There were no increases of heating costs determined.Further studies are needed to optimize the heating parameters and reach the desired greenhouse productivity.

Theoretical background for increasing grip properties of wheeled tractors based on their rational ballasting

ArticleSaabunud / Received 30.07.2019 ; Aktsepteeritud / Accepted 07.10.2019 ; Avaldatud veebis / Published online 15.10.2019 ; Vastutav autor / Corresponding author: Jüri Olt e-mail: [email protected] correct selection of the level of mechanical ballasting for wheeled tractors is among the most important issues for increasing their utilisation efficiency, in particular, increasing their grip properties. The shortcoming of the earlier undertaken investigations was that they virtually did not take into account the allowed maximum pressure of the tractor’s wheels on the soil. At the same time, little attention was paid to the impact of the maximum load-carrying capacity of the wheel tyres. The aim of the paper is to eliminate these deficiencies. Because of the authors’ efforts, the new technique has been developed, which differs in that it employs the requirement of the tyre’s ecofilic properties. The implementation of this requirement implies setting the maximum allowed level of the tractor wheels’ pressure on the soil and taking into account the maximum load-carrying capacity of the wheel tyres as well as the vertically applied load on each of the tractor’s axes under the simultaneous action of both the horizontal and vertical components of the tractive resistance of the employed agricultural implement. The practical effectiveness of the new approach is shown by the example of determining the possibility and level of ballasting the specific wheeled tractor operating as part of a ploughing unit

A New Spiral Potato Cleaner to Enhance the Removal of Impurities and Soil Clods in Potato Harvesting

Sustainability in the agricultural field suggests the conservation and maintenance of a natural environment of soil. Nevertheless, in the potato production chain, the mechanized harvest is carried out with the concurring removal of impurities and fertile soil. The authors have developed a new spiral potato cleaner which is able to capture and efficiently remove soil lumps of various sizes and shapes, as well as various plant residues. Theoretical and experimental studies have been performed on this soil clod cleaner to determine the structural and kinematic parameters that provide efficient capturing, motion and sifting down of the soil, through the gaps between the helices of its cleaning spirals. An analytical description of the motion of the clod of soil has been made and a system of differential equations has been compiled, whose numerical solution made it possible to determine the indicated reasonable operative parameters of the developed spiral potato cleaner. The results of the experimental research confirmed those ones obtained through the numerical solution of the mathematical model, i.e., rational angular speed ω of the rotation of the spirals from 20.0 to 30.0 rad s−1 and the radius R of spirals between 0.12 and 0.15 m

Air Heating Solar Collector for Hemp Drying

Attempts to use solar energy for drying of hemp (and other agricultural production) have been made in this work. Air is heated in solar collector approximately to 40 – 60 degrees Celsius, which also results in decreasing of the humidity of this air from 60 % (normal ambient air humidity) to 18 - 8 % respectively. Then such hot dry air is used for drying of hemp or other agricultural production.A new construction of air heating solar collector – a cylindrical solar collector has been worked out

The effect of a lateral airflow created on nozzle tip on the spray droplets deposition

Saabunud / Received 02.09.2021 ; Aktsepteeritud / Accepted 11.12.2021 ; Avaldatud veebis / Published online 11.12.2021 ; Vastutav autor / Corresponding author: Jüri Olt [email protected] application efficacy of a plant protection products by using a pneumatic device to change the dispersion of spray droplets is depended on the intensity of crosswind. The laboratory investigations of the spraying process of plants by means of the nozzles of a pneumatic system determined the quality indicators of pressure in the injection process of 0.4 MPa – the droplet coating density of 19–46 pcs cm2 –1 for the weighted mean droplet diameters (WMD) in the other experimental variants was within 304–543 μm. These indicators were compared with those for the standard, anti-drift and air injection nozzle types in which the droplet coating density was 23–59 pcs cm2 –1 and the weighted mean droplet diameters (WMD) were in the range of 350 to 485 μm. An analytical dependence was obtained of the influence of the lateral airflow and air pressure in the pneumatic system upon the amount of the deposited spray liquid

Study of the steering of a wide span vehicle controlled by a local positioning system

Controlled traffic farming allows to minimize traffic-induced soil compaction by a permanent separation of the crop zone from the traffic lanes used by wide span tractors. The Authors developed an agricultural wide span vehicle equipped with a skid equipment for turning and an automatic driving system prototype based on a laser beam. The aim of this work was to study the kinematic conditions that control the steering of this machine. Furthermore, the accuracy and the maximum delay time of the signal transmission by the automatic driving system of the set-up was also assessed. In comparison with crawler tractors, the turning of the agricultural wide span vehicle needs a smaller difference in the moments applied to its right- and left-side wheels. For the predetermined accuracy of the beam position relative to the plant rows, ±ds = ±0.025 m, the accuracy of the direction of the laser beam at a distance S=200 m should not be more than ±0.07° and ±0.0014°, considering a run length of 1000 m. Furthermore, at a speed V=2.5 m s–1 a trajectory deviation φ≤5° requires a topmost delay time of the control signal of Δtmax=0.11 s is required

Research of possibilities for efficient use of wide span tractor (vehicle) for controlled traffic farming

In part, the economic effect gained from the introduction of controlled traffic farming can be directly determined by the area of the field lost under the engineering (or traffic) zone of the vehicles involved. With a wide span tractor, as with other vehicles, the area lost under the traffic zone will depend upon how efficiently operations in the field are organised. The purpose of the present investigation is to substantiate the design and other parameters of the wide span tractor from a position of efficient land use in controlled traffic farming. Theoretical studies, synthesis of the construction diagram and parameters of the wide span tractor were carried out using computer simulation of its operation. These studies indicated that planning of the field for controlled traffic farming with the use of a wide span tractor should take into consideration its track width and its field operational parameters. The use of a contemporary design of wide span tractor with a track width more than 7.5 m results in field traffic zone losses of no more than 5 -6 %, which is quite acceptable. Practical use of a wide span tractor for controlled traffic farming needs automatic steering to reduce field traffic zone area losses by a factor of 1.5 times compared with manual steering

Research of a contact stresses in swivel elements of flexible shaft in screw conveyor for transportation of agricultural materials

Saabunud / Received 12.03.2022 ; Aktsepteeritud / Accepted 28.04.2022 ; Avaldatud veebis / Published online 28.04.2022 ; Vastutav autor / Corresponding author: Jüri Olt ; [email protected] paper presents the new design of the rotating part with ball-bearing swivel joints between its sections for flexible screw conveyors. The new design provides for the improvement of the operation efficiency and loading capacity, the enhancement of the technological capabilities and the reduction of the admissible curvature radius. The contact stresses in the swivel element as the most loaded area in the rotating part have been analysed. It has been established that the maximum contact stresses arise at the points of contact between the ball and the flat surface of the slot in the cylindrical bushing. The recommended design limitation range for the cavity cone angle is within about 30–50. The relation between the loads and the stresses depending on the operating conditions has been modelled with the use of computer modelling. The comparison of the computer modelling results and the obtained calculation data has proved that the difference between the respective values varies within the range of 11–26%