Table of Contents


    • Justification of kinematic parameters of coupling for wide-span row-crop unit

      pg(s) 156-158

      Effective use of the KhTZ-160 tractor is possible, with the specified width, combining the implementation of the main technological process with an additional, i.e. sowing with cultivation. Shows the results of calculations of the transverse displacements of the working bodies as a function of their placement along the width of unit and along its length relative to the transverse geometric axis that passes through the kinematic the center of the tractor without taking into account the curvature of the trajectory of tractor and possible changes in the position of kinematic center along the unit. The largest values of the transverse displacements of the working bodies, which are placed at a distance of 2.6 m, i.e. at the machine which is attached to the rear hinged system of the tractor, reach 14.5 cm at maximum angles of rotation of the unit (3 degrees). The smallest transverse movements of the working bodies are observed when placed on a geometric axis that passes through the axis of the rear wheels (less than 1 cm). The lateral movements of working bodies of 18-row wide-coverage row-crop unit depending on the tractor turning angle and their placement in the unit are considered. Kinematic parameters and coupling scheme are recommended.


    • Biogeochemistry of lignin in soils of mountainous landscapes

      pg(s) 159-162

      The relative proportions of lignin phenols are determined by the phylogenetic origin of plants and allow the formation of various low- and high-molecular-weight products of lignin decomposition in the soil, which are involved in humus formation. A whole spectrum of transition vegetation zones are concentrated in the mountain landscapes. The immediate aim of this work was to study the transformation of lignin structures in the soils of different mountainous ecosystems of Tian-Shan and Caucasus. The determination of the lignin in the plants, and soils involved the alkaline oxidation with copper oxide at 170° C under pressure in a nitrogen environment. The phenolic components of the lignin were separated using a gas-liquid chromatography. The composition of lignin phenols in soils serves as a molecular trace of land vegetation and palaroenviromnents.

    • The increase in the yield of vegetables in greenhouses using supercavitation treatment of irrigation water

      pg(s) 163-166

      The use of hydrodynamic and thermophysical effects of cavitation (cavitational technology) facilitates mechanical thermolysis of the water structure with free hydrogen bonds production, dispersion and solution annealing treatment to produce resistant emulsions, suspensions, and mixtures finally promising to improve and intensify the processes in various industries. There are given the results of the cavitation treatment effect on the properties of water which at times is a dispersed phase and at other times is a dispersion medium. In agriculture the use of the cavitation-treated water allows to get a crop capacity gain for greenhouse vegetable cultures up to 30 % with simultaneous reduction of plants morbidity. It is obvious that the major factors influencing the produced effect are the increased oxygen content of the treated (activated) water as well as the complex physical and chemical processes occurring under the cavitation effect: redox reactions that proceed in the water between the dissolved substances and the water splitting products emerging in cavitation bubbles and passing into the solution after their collapse; reactions between the dissolved gases inside cavitation bubbles; chain reactions in the solution initiated by the products of splitting in impurities cavitation bubbles; macromolecules break-down and its initiated polymerization; water structure change with the production of free hydrogen bonds, etc.

    • Design of irrigation systems for gardens by alternating greywater and well water

      pg(s) 167-170

      Water is the basic source of life for plants, animals, and humans. However, the impact of climate change drastically reduces its sources. Rational consumption of clean water leads to the need for finding alternative water sources for irrigation of gardens. As an alternative source, greywater can play an important role. Greywater is waste water from households, which does not contain faecal compounds. The aim of this paper to present design concepts of systems for collecting, purifying and application of greywater and well water for irrigation of gardens. The concept is developed using previous own research results, as well as available literature, on the benefits and risks of using greywater, and the effects of purifying greywater and well water through various treatment systems. The paper presents two systems: (1) a system which allows the storage and irrigation using raw greywater and (2) a system where greywater supply is not continuous. The second system is suitable not only for households but also for other facilities, e.g. touristic, recreational and weekend resorts. This system proposes alternate irrigation with grey and well water for resolving two problems: inappropriate greywater quality and inappropriate water quantity. In general, the system reduces the risk of soil degradation and is water saving by automatically adjusting irrigation with regard to the soil moisture content.

    • Surface water resources assessment methodologies application in case of Vit river

      pg(s) 171-173

      The surface water resource determination is an important issue related to most reliable water management, which in some districts of Bulgaria in some periods are not enough. In this aspect, the present work is part of the effort to create an operational tool to assess the annual resource. Annual, because this is one of the periods of planning the water use, on the other hand annual averaging significantly simplifies the water balance equation.
      There are several methods in world practice for this purpose: modeling the process “rainfall – runoff”; regionalization in typical water quantities depending on physico-geographic factors; balance approach. The first one require a serious resource of information and time, mainly used to analyze the impact of decay factors and climate change rather than on operational purposes. The method of hydrological regionalization is already operational in use, but as far as it is based on registered river flow, it is important to clarify the influence of anthropogenic factors. The water balance method is widely used for the purposes of the Water Framework Directive, both for the assessment of the water bodies’ resources influenced by human activity, as well as for analysis of pressure and water stress, for water economic balances, for the management of water abstractions and river basins. It applies to WB category “lake” – large dams; WB with resource dependent on technological input from dams or derivations; WB with additional flow of water transfer, etc. Vit is one of the main bays in Northern Bulgaria, combining a mountainous, hilly and plain area, on average in area, presenting relatively well the characteristics of formation of the river flow. There are three significant dams, two irrigation systems, derivations and water transfers and a significant number of smaller consumers. In this sense, the basin is chosen as representative, with the opportunity to demonstrate the methods. The balance method is applied to typical sub-basins for the period 2015 -2017.
      As a result, a hydrological evaluation of the surface water resource was made for the selected sub-basins based on the registered flow and the water balance assessment of the surface water resource for the same sub-basins. A comparison was made, conclusions were drawn about the advantages and disadvantages of the methods and their applicability in practice.

    • The impact of long rotation cycle forest management on soil and water properties in Hemiboreal region

      pg(s) 174-177

      More than a half of Latvia’s territory is covered with forests, and forest sector is important for the national economy. Despite the high economic importance of timber resources, forest utilization in Latvia is moderately intensive, as long rotation cycle (70-100 years for most widespread tree species) is used and strict environmental regulations are in force. Meanwhile, due to the climate change and growing demand for renewable resources, intensification of forest management is ongoing and expected to continue. Studies on the interactions between forest, soil and water are of high importance to ensure sustainably intensified forestry. Forest felling, transportation of logs, collection of slash, stump extraction, drainage system establishment and maintenance, forest road construction, beaver population management, use of water protection structures and riparian bufferzones are apparent components of forestry that may exacerbate, change or improve quality of water, soil and stands, and as such, require research and practical application of relevant protection measures.

    • Multi-component adsorption of heavy metal ions from aqueous solutions onto low cost adsorbent based on rice husks

      pg(s) 178-181

      A novel low cost adsorbent based on rice husks was obtained by slow pyrolysis at temperature 350°C and was characterized by means of SEM, Hg-porosimetry and N2-adsorption. The adsorption properties of the investigated material towards Fe(III), Pb(II), Cr(III) and Cu(II) ions in multi-component aqueous solutions with different concentrations and acidity were studied in a batch system. The adsorption of metals is significantly affected by the pH value. Equilibrium experimental data were fitted to linear Langmuir and Freundlich model and maximum adsorption capacities were calculated. Kinetic of adsorption in multi-component solutions was also investigated

    • The influence of perennial legumes, legume-festulolium mixtures and their mulch on soil mineral nitrogen under organic cropping conditions

      pg(s) 182-185

      Legumes are one of the major nitrogen sources in arable organic farms. Often the aboveground mass of perennial legume is used for green manure. The study was aimed to explore the aboveground mass of perennial legumes and their mixtures with festulolium, used as mulch, to estimate soil mineral N variation under organic cropping conditions. The perennial legumes (Trifolium pratense L., Medicago sativa L.) and their mixtures with festulolium (x Festuliolium) and their aboveground mass management methods: removed from the field (cut twice for forage), mixed management (the first cut – removed from the field, the second and third cuts – mulched), mulching (4 times) in organic arable farming system were applied. After ploughing up of mulches, the dynamics of soil mineral nitrogen content depended on the incorporated carbon and nitrogen of mulch, its C/N and meteorological conditions during the whole vegetation period. The compatibility of nitrogen release from incorporated organic matter and cereal nitrogen demand was established not every years. The amount of soil mineral N in the autumn can be controlled by growing mixtures of legumes and festulolium and by incorporating a limited amount of mulch into the soil.

    • Geoinformation mapping for providing the rational use and protection of soil

      pg(s) 186-189

      The approach to design of the system of geoinformation mapping to support making the land management project or management decisions for soil conservation were shown in the study. Developing the conceptual, logical and physical models of geodatabase to provide mapping of arable land condition was shown in the study. A set of thematic maps, designed as combination of relief, climatic and soil conditions, would be very effective to the land management in optimizing the rational use and protection of land.

    • Reduction of losses from drought by optimizing the use of water resources for irrigation of agricultural crops

      pg(s) 190-192

      Drought is a major problem for plant breeding in the country during dry years. This, in parallel with the increase in the technical capabilities of agriculture, has put more emphasis on overcoming the drought phenomenon. For this purpose, efforts have been made both in the development of relevant technical concepts and in the development of appropriate methodologies and technologies. The most important activity in this direction is the redistribution of water resources mostly over time. The report presents some aspects of overcoming the effects of drought by optimizing the use of water resources.