Table of Contents

  • CONSERVING OF THE RESOURCES

    • TYPES OF TILLAGE AS A PREREQUISITE FOR RETENTION OR ALTERATION OF PHYSICAL AND MECHANICAL PROPERTIES OF SOIL

      pg(s) 11-16

      The physical and mechanical properties of soil change dynamically following each tillage and rainfall. Some of the more important ones are bulk density, (g cm−3), hydraulic conductivity in soils, saturated with water, (cm day−1), the rainfall curve, the temperature (оС) and the capacities of soil to retain water at saturation point (cm3 cm−3). Theoretically, only the upper 30 cm of soil layer experience change in the physical and mechanical properties, caused by tillage. The actual depth of the changes in the soil depends on the production technology selected. Various types of tillage are applied worldwide, corresponding to the level of development of socio-economic formations and of the production technologies. In Bulgaria, the traditional annual ploughing of soil is applied, including on slopes, giving a prerequisite for the subsequent negative consequences, such as activation of erosion processes and degradation.

  • MECHANIZATION IN AGRICULTURE

    • THE EXPERIMENTAL VALVE DEVICE FOR THE GRAIN CONSUMPTION REGULATION

      pg(s) 1150-5

      For the ensuring of uniform grain supply the silo has to be equipped with various portioning devices. The feature of the most widespread locks is the fact that at each lock opening – closing, the grain is damaged. In the article the authors describe the experimental valve device consisting of two regulating shutters: vertical and rotary. The developed experimental valve device minimizes grain damage at each cycle of an opening – closing. The statistical mathematical model is developed considering the influence on grain consumption of unloading crack height and a rotation angle of a rotary shutter. The obtained results will be used in the development of the automatic control system of grain consumption.

  • CONSERVING OF THE RESOURCES

    • RICE IRRIGATION TECHNOLOGY ON SALINE LANDS

      pg(s) 17-19

      Rice production on the irrigated lands of the Syr Darya river basin (the Aral Sea region) is a traditional specialization of the agricultural sector. If on the mildly saline soil rice yield reaches more than 5 t/ha, then on highly saline soil rice yield is below 2 t/ha, which makes its cultivation not profitable. Those lands degrade and eventually excluded from agricultural use. We studied the rice irrigation technology of saline lands, which enables to provide rice yield of 4 tons per hectare and above.

    • THE ASSESSMENT OF THE EFFECTS OF THE ATMOSPHERIC PRESSURE ON THE INTENSITY OF CO2 EMISSION FROM POLISSYA SOILS IN THE COLD TIME PERIOD

      pg(s) 20-22

      The paper presents the results of the investigations into the effects of the atmospheric pressure on the intensity of CO2 emission during the cold time period from podzolic soils of Ukraine’s Central Polissya. It is shown that due to global warming, the winter period getting milder, against the background of less intensive soil freezing, the part played by the atmospheric pressure in intensifying the carbon dioxide emission from the soils, along with their temperature, is becoming quite significant. It has been established that the values of CO2 emission from podzolic soils of Ukraine’s Polissya after the “the post – freezing” period (III) are significantly higher as compared to the corresponding values of “ the pre-freezing” period (I) of the cold period of 2015-2016.

    • ESTABLISHING THE INFLUENCE OF HEAVY METALS IN THE SLUDGE, ON THE YIELD AND QUALITY OF PRODUCTION ON SEVERAL SOIL VARIETIES

      pg(s) 23-25

      The aim of this experiment is to determine to what levels of toxic load with heavy metals reached different soil types under varied levels of sludge application. Determine the effects of different toxic loading soil on biomass yield and heavy metals content in crop production. The pot experiments are with two cropsperco(Brassica ssp. spantaula) and rye grass(Loliummultiflorum), in two swaths as an after-effect on the yield on four soil types: Carbonate Fluvisols,Leached Vertisols, Leached Cinnamon Forest and gray Forest.The different percentage of sludge level relative to the weight of soil was tested.

      It was found, that loading of various soils types with sludge up to 10% supported increasing effect of fertilization with sludge in perco and rye grass and to the same extent accumulation of heavy metals in them. Their concentrations, however, do not have phytotoxicity.

    • THE MODIFICATION OF SOIL PROPERTIES AND PLANT UPTAKE BY THE APPLICATION OF BIOEFFECTORS AND AMENDMENTS

      pg(s) 26-29

      Physico-chemical properties of biomass ashes and biochar were significantly different. Strong differences were also caused by the choice of feedstock materials for incineration, which is demonstrated by different composition and solubility of wood and straw ashes. Availability of nutrients was the highest for K among all tested macronutrients. The application of ash did not adversely affect the growth and yield of plants, neither the accumulation of nutrients in plants and soil. The inoculation of soil by bioeffectors did not affect plant yield but positively influenced the solubility of P. Ash and biochar support sorption and immobilization of toxic metals in soils causing either their lower accumulation in biomass or promoting the growth on the extremely contaminated soil. Both applied materials showed their ability to improve soil properties and support plant growth.

  • MECHANIZATION IN AGRICULTURE

    • THEORY OF TWO-DISC ANCHOR OPENER OF GRAIN DRILL

      pg(s) 6-8

      High seeding quality of grain crops under modern technologies causes increase of requirements to seeders opener. We developed a new design of the combined two-disk anchor opener which can qualitatively carry out their functions under modern technologies, in particular no-till. Research purpose is development of the functioning theory of the created new furrow-opener design which integrates in itself constructive elements of two-disk openers and anchor type openers and can works on roughly prepared soil with plant residues and provides the stable seeds sowing depth at the increased seeding speeds. When carrying out researches methods of mathematics, theoretical mechanics, modeling, researches results statistical analysis, drawing up programs for calculations on PC are used. Parameters of the combined two-disk opener with the advanced mechanism of sowing depth regulation are substantiated. On the basis of the scheme of a opener design it is proved need of using certain rigidity spring for stability seeding to a predetermined depth within the agrotechnology limit.

      Dependences for calculation of rational spring elasticity which take into account geometrical parameters of opener design are obtained. The pilot studies conducted in field conditions confirm advantages of new constructive decisions of this combined opener. It is established that the seeder with the combined two-disk anchor openers steadily puts seeds on a compacted seed bed that excludes inertial seeds ejection beyond the agrotechnology limits, including at the increased seeding speeds.

    • MODELING OF MACHINE-TRACTOR UNITS WORKFLOW ON THE USE OF BIOFUELS

      pg(s) 9-10

      It is considered in the work integrated mathematical model of the machine-tractor units (MTU) that takes into account the physic-chemical properties of biofuel. The novelty of this model is that it takes into account the impact of the working processes in the structural elements of the MTU, one by one influencing each other. This scientific approach to the calculation of the MTU provides the opportunity to evaluate objectively the impact of biofuel on the operational and technological indicators, taking into account the weather conditions, the physical and mechanical properties of the soil and other conditions that may diminish the impact of biofuel on the operation of the unit and distort the final results. In addition the model is adapted to use computer applications, which makes it possible to reduce significantly the complexity of the calculations and reduce the influence of the human factor.