Table of Contents

  • Study plane-parallel motion movement combined seeding unit

    pg(s) 184-187

    Conducted analytical studies, resulted in the construction of a new mathematical model of plane-parallel motion combined simultaneous sowing unit and bandpass mineral fertilizers. If you use the original equation in the form of Lagrange II-the kind, the system was composed of six differential equations of motion, that describes the behavior of the combined unit with its plane-parallel motion. Defined analytical expressions for the forces, that act on the machine unit, can be solved on the PC.

  • Laboratory and field equipment workingout and the results of experimental studies of pre-harvesting sugar beet field conditions

    pg(s) 188-190

    Described in the scientific literature the results of experimental studies and performance test of the technological process of sugar beet harvesting conducted in recent years have shown that modern sugar-beet harvesters manufactured in Europe and America work with significant losses of sugar-bearing plant materials. These losses are due to generally poor topping quality of sugar beet on a root. Therefore, nowadays the search of technical solutions enabling to avoid these losses is of great to importance as it increases the yield of sugar-bearing plant materials per hectare of crops. The purpose of research is to reduce the losses of sugar-bearing plant materials in the course of separation process of sugar beet tops from heads of root crops on a root. While conducting research the methods of field experimental research on the measurement of physical parameters of the technological process were used, as well as methods of statistical processing of the measurement results with the use of computer. New experimental equipment was designed for the field experimental studies being equipped with modern electronic equipment with data transfer to a PC. As a result of the experimental investigation of the distribution heads heights above the ground of sugar beet roots confirmation has been received hypothesis that it does not deny the law of the normal distribution. The results of the multiple measurements enabled set limits of changes in their statistical characteristics, which are as follows: average statistical deviation σ = 20 … 30 mm, the expectation m = 40 … 60 mm. A new design of the laboratory equipment and results of the experimental studies, conducted on it, have given every reason to design and develop a new system of automatic adjustment of the height of cut tops, which can be used in designs of modern sugar-beet harvesting machines.

  • The batch-combined minimum tillage farming machine

    pg(s) 191-194

    The working members of the batch-combined machine for minimum tillage and crop tending are combined into two separate batches. By means of the first batch, there are performed simultaneously tilling and sowing operations, but the second is intended for surface tillage and crop tending. During just one field day, the machine is capable of performing 8…10 agricultural operations, and its working members can work in three modes: 1. Soil loosening without furrow slice overturning, when the main tillage unit (wedge) is in its working condition together with lateral knives (for the eroded soils); 2. Clod furrow slice pulverization and mixing, when the main tillage unit (wedge), lateral knives and rotary tiller are in their working conditions (for the non-eroded soils); 3.Cultivation of humid soils with a partial overturning of furrow slice, when the main tillage unit (wedge), lateral knives and rotary plough (instead of tiller) are in their working conditions. The cost of oil and lubricants and operating time are reduced by 2…2,5 times, and besides, the agrotechnical terms reduce considerably. The design formula for tillage output envisages both broken and unbroken soil strips. This formula can be also used for calculation of the machine output during cultivation, sowing, cutting the irrigation channels and so on. The proposed batch-combined machine can be also considered as energy-saving, resource-saving, environmental and advanced technology.

  • Optimization of tribological parameters in the design of rotary tiller blades

    pg(s) 195-199

    The argument of this paper is rotary the tiller blade, which undergoes severe surface wear during tillage of agricultural land. The study was conducted by comparing on H-shaped blades, of two different manufacturers, used in rotary tillers, mainly in the fields of Myzeqe, Lushnje. Our tests included the measurement of the abrasive wearing as weight loss of material of each blade to the end of lifecycle – recorded after every 10 hectares cultivated surface in field conditions. We experimented in laboratory the blade wearing through ‘pin on disk’ test. Another tribological parameter measured in the laboratory was the hardness in Vickers on cutting edge of the blade, before and after wearing. To make the targeted optimization, we initially computed a stressed situation on the blade cutting edge, and then processed through the SOLIDWORKS software, which generates a map of more stressed areas that lead to significant wear. By simulating with geometric parameters of tiller blades, we have sought the situation of stresses with less impact on wearing of tiller blades. This paper is also includes relevant recommendations.

  • Optimization of the frequency of the technical service of machines with reliance of reliability

    pg(s) 200-202

    A key element in the machinery management policy is its rational use by optimizing the periodicity of maintenance and repairs. The influence of the numerical characteristics and parameters of the reliability indicators distribution on the optimal periodicity of the maintenance has been investigated. Analytical dependencies for determining the complex reliability indicators of the objects at the optimal periodicity of the prophylactics are proposed.

  • Optimizing the periodicity of machine maintenance with respect to the underused resource

    pg(s) 203-204

    The intensity of aging and wear of the components /aggregates and assemblies/ of the machines is different and hence the necessity of carrying out repair service interventions has different periodicity and volume.
    A model has been developed to optimize the periodicity of maintenance of machine components, taking into account the losses from the underuse of their resource.
    The influence of the parameters of the law and the economic indicators on the optimal periodicity of the maintenance was examined at the density of the distribution of work until failure to the Weibull distribution.

  • Innovative moments in training bachelor degree students in “Crop Production”

    pg(s) 205-207

    Dynamically developing plant growing continuously sets challenges to the system for training specialists, who have to be able to develop competitive and sustainable agriculture. In the conditions of market economy and various forms of land management, for the development of plant growing are needed managers and executives, who will be able to apply successfully the scientific principles of research, analysis, support and management of cost-effective agricultural production units. The degree programme Plant Growing provides preparation of such specialists. Education in Crop Science and Production offers such kind of training by application of innovation moments such as practical semester and development of integrated project.

  • Technological and economic aspects of drip irrigation of raspberries

    pg(s) 208-210

    Drip irrigation provides a fairly even mode of moisture in the soil and, along with this, favorable air, heat, microbiology and nutrition. As a result, there is an increase in yields and an improvement in the quality of production.
    In order to determine the impact of drip irrigation, on the size of the yield and the economic indicators, in the cultivation of raspberries in the soil and meteorological conditions of the area of the village of Chelopechene – Sofia researches of an everbearing variety “Lyulin” were carried out. Various options have been tested – from fully satisfying the daily needs of the culture by water, irrigation with 20% and 40% irrigation norms to non- irrigating conditions.
    The results obtained in years with different security of meteorological factors show that the drip irrigation of raspberries has a positive effect on the economic indicators of its cultivation, the costs of creating the raspberry crop, the irrigation system and the cultivation of the crop are redeemed for two or three years.

  • Role of mineral substrates in formation of humic compounds in soil

    pg(s) 211-214

    The effect of mineral matrices of loam, quartz sand, sand + 30% kaolinite, and sand + 15% bentonite on the dynamics of transformation of plant residues (PRs) of corn and red clover was studied. It is shown that the dynamics of PRs transformation has a wave pattern and depends both on the nature of mineral matrices and on the composition and properties of PRs. The kinetic parameters of corn and clover decomposition were studied, using a two-term exponential polynomial. The turnover period for the labile pool of clover and corn in all substrate (8-10 days) is typical for the organic acids and simple saccharides. The turnover time of the stable clover pool (0.95 years) and of the corn (1.60 years) corresponds to the turnover time of plant biomass.

  • Effect of using a complex of agro-technical practices on planosols

    pg(s) 215-219

    The problem of updating agricultural technology, particularly in the field of agriculture, is important for agriculture. Alternative technology solutions that meet the performance criteria are a prerequisite for successful economic activity.
    The aim of the study is to determine the effect of the application of an agro-technical complex of events, which successfully supports the soil fertility of the Planosoils and the sustainable level of productivity of the field crops.
    In the field experiment in the station for irrigation agricultural Pazardzhik Valley, in three-polar crop rotation maize-barley-rape are studied three factors – soil tillage system, mineral fertilization and ways of managing plant residues.
    The study found that the moisture content of the soil was mainly influenced by the type of treatment applied (loosening as a main plow and plowing as a pre-sowing) and the use of plant residues. The over compaction found in the beginning of the experiment in the 25-40 cm layer is partly overcome by performing a deep rupture to the depth of 35 cm. Despite the short period of the study, there was a certain decrease in the content of digestible potassium forms. The results show the activation of the microbiological activity after planting of the plant residues – an increase of the amount of the cellulose microorganisms and of the ammonifiable bacteria, the most noticeable in the high fertilization rate and the intensive treatments. The main part in the formation of crop rotation productivity is mineral fertilization. The impact of the tillage system is more marked in the first year of maize and especially during the third year of rape. Lack of fertilization influences yields significantly in rapeseed compared to maize and barley.

  • Sustainability of agricultural production and its impact on the policy and environment

    pg(s) 220-222

    The World Commission on Environmental Sustainability (1987: 43) identified sustainability as addressing current needs without compromising on the possibilities of taking the resources of future generations. Although this definition seems sufficiently well formulated, it has about 40 different definitions of the concept of sustainability in the context of policy actions and their implementation throughout the process.