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  • Utilisation of subsurface waters for soilless vegetable forcing in the Southern Great Plain region of Hungary
    43-45.
    Views:
    224

    For soilless vegetable production of the Southern Great Plain region in Hungary, there is enough water available, however, the origin and chemical composition of it are decisive from the point of view of practicability. The ground water is everywhere accessible, although its sodium and chloride content is almost always significant, moreover, human pollution may occur (e.g. nitrates and phosphates). A further unfavourable moment is the seasonal variation observed within the area of the same community. The abundant supply of water in the Quaternary strata are located in more than half of the cases within the upper 50 m region. As by the expected changes of the climate, a strategic increment of the importance of subsurface waters is anticipated. Their composition is relatively stable, and the prognoses are reliable for the same settlement. Salt content of the majority of water resources bearing hydrocarbonates is low, however, streaming of the subsurface waters tend to increase their sodium content and to diminish their calcium and magnesium, whereas the pH increases (mainly by ion-exchange). Water quality is decisive not only because of the interaction with the plants but also from the point of view of the distribution of water. Some micro-elements, mainly iron and secondarily manganese may cause problems, therefore, irrigation water ought to be prepared carefully. Production technology should be completed by a technical equipment using aeration for the elimination of ironinfluence of yields on rate of return of investment; (3) the role of increasing of added value content of products. Importance of the utilisation of alternative channels of distribution and the formation of producers' cooperatives are underlined, being based on calculation of return of investment.

  • Modelling and comparing two canopy shapes using FEM
    71-74.
    Views:
    171

    Central leader and Vase form canopy models were built using FEM. Their main characteristics were chosen to be the same. The models were virtually exposed to the effect of steady-state horizontal forced vibration in the frequency range of 0-20 Hz. Acceleration-frequency curves were calculated and drawn to find the best frequency values for the effective detachment and also to see the acceleration differences in the limbs. For the same purpose the direction of shaking was also changed. It was found that for the Central leader canopy shape multidirectional shaking would bring uniform detachment while for the Vase form trees also the unidirectional shakers were appropriate. The acceleration achieved for the Vase form models were much higher than for the Central leader type. The acceleration-frequency curve of the shaker unit can be used to find the best frequency for shaking.

  • A review of the bee pollination research on temperate zone crop plants in the past decade: results and the need of further studies
    7-23.
    Views:
    289

    Intense research was made on the pollination of cultivated crop plants in the temperate zone region during the past decade. Some 400 publications appeared on the subject and some additional 150 papers on the effect of pesticides to the most important pollinating insects, the honeybee and the wild bees. Progress of knowledge is discussed in this paper based on the most important publications. Most new results relate to field crops and deciduous fruit species and much less to field vegetables and small fruits. Great effort was taken to improve insect pollination of crops grown under cover. All these are connected to the utilization of the honeybee as a pollinating agent and much less to native or managed wild bees. However, a number of questions arose partly from the results of latest pollination research and partly from practical experiences in commercial plant production. These indicate several research tasks to understand and to solve the problems possibly in the near future. The questions concentrate on the effectiveness of bee visits in the pollination of individual crop plants and their different cultivars and on the reliable estimate of the overall amount of bees as well as on the control of bee density during the flowering periods of crops for optimal, controlled pollination in the changing environment of agricultural crop production.

  • Detection and identification of phytoplasmas in peach based on woody indexing and molecular methods
    35-41.
    Views:
    248

    Symptoms resembling phytoplasma disease have been observed on peach trees in a seed-source plantation of stone fruits in south Hungary quite recently. In this publication we report on the results of woody indexing of symptomatic peach trees on GF 305 indicator in the field and under greenhouse conditions as well as on molecular studies. Phytoplasma infection detected on GF 305 indicators in greenhouse and field indexing was confirmed by PCR. Nested PCR was conducted using universal primer pairs followed by group and subgroup specific primers for the second amplification. RFLP analysis of nested PCR products was performed using Rsal restriction enzyme. Based on the results of molecular studies it can be concluded that phytoplasmas, belonging to the European stone fruit yellows subgroup (16SrX-B) were identified in peach trees. Further studies on symptomatic peach trees originating from different parts of Hungary are in progress.

  • Some flower characters, variety features and environmental effects affecting bee pollination of pear (Pyrus communis L.): a review of the results of latest research
    59-66.
    Views:
    306

    Intensive research has been implemented on different aspects of the bee pollination of pear in Hungary in the past decade, extending to the following topics: the effect of the opening sequence of the flowers within the inflorescence of pear cultivars on the effectiveness of bee pollination; the nectar production of flowers of pear cultivars; intensity of honeybee visitation and their foraging behaviour at the flowers of pear cultivars; flower constancy of honeybees to pear plantations; competition by weeds in bloom for bee pollination in flowering pear orchards; and some aspects to the bee pollination strategies of pear plantations (the effect of the limitation of bee pollination period on the set and the yield, possible compensation of frost damage of flowers by bee pollination in pear orchards, the optimal size of single cultivar block in pear plantations). The results of these studies are reviewed in this paper and some important aspects that need further studies are outlined.

     

  • Comparative study of cherry varieties used in intense culture
    71-74.
    Views:
    279

    Research in sweet cherry production is intensely stimulated worldwide. The programs started also in Hungary to develop technologies and to find suitable varieties for the purpose of intense cultivation. It means that dimension of crowns should be smaller, with higher number of plants per hectare. Understocks, which let grow the trees slower, are scarce in this species. On the one hand, the braking effect of the respective stocks is insufficient, they get old pretty soon, loose ramification, yield too small fruits and do not comply with the aims of intense cultivation. Experiences prove the necessity of stocks for intense culture, which are vital, growing, easily regenerating, and freely branching. Mahaleb (Prunus mahaleb), a strong growing stock, is still suitable. Further improvement is expected from the contribution of technological elements and the choice of variety. In the present paper, a 9-year old plantation is shown with trees trained to (slender) spindle, and the yield and fruit quality of the year 2009 has been analysed with 6 varieties involved.

  • Work organization and economic analysis of the postharvest of an unique Hungarian product
    11-14.
    Views:
    208

    We have viewed a business in the south of the Great Plain Region from an economic point of view in 2004-2005. The main activity there is pear growing and storage. Four varieties of different time of ripening and storing are grown there. We have measured all the relevant activities, worked out a local normative and prepared a detailed technology. The economic evaluation was based on this data. Activities, like disinfection, pre-storage disinfection and selection, in-storing and out-storing, classification after storage, packaging, as well as loading trucks, were monitored by variety. Storage loss was determined and widely varied according to varieties, length of storage and time of out-storing. Different varieties resulted in different quality classes after storage. Price depended on the quality classes. Economic evaluation was carried out when all the relevant costs and revenues were known. Fixed and variable costs of storage were determined, break-even point was calculate and the market position of the product was evaluated.

  • Experiments on the Resistance or Pepper Cultivars to Macrophomina phaseolina
    74-75.
    Views:
    220

    The ashy stern blight of pepper (Capsicum annuum) is often caused by Macrophomina phaseolina. Serious wilt disease occurred between 1994 and 1996 of pepper plants in Hungary. In 1996-98 screening experiments were made on many pepper cultivars. Culture (Knopp) solution experiments, pot experiments, greenhouse and field trials were carried out. We determined the incidence of disease by visual examinations, testing on PDA culture, and light microscope. There were significant differences in susceptibility of cultivars and breeding materials.

     

  • Vegetative Indicators of sour cherry cultivars and resistant clons
    55-58.
    Views:
    305

    Sour cherry is a hungaricum. Hungary has several excellent and self fertile sour cherry cultivars. Hungarian sour cherries have a name for fruit quality and they are suitable for fresh consumption. Today breeding is focused not only on fruit quality, but also on disease resistance. The new, investigated cultivars have these characteristics too. But growth characteristics are also very important because they contribute to successful production. The vegetative and generative properties of the cultivars are different. If a cultivar is very productive, the ignorance of cultivar-specific pruning may result in the decrease in tree condition and fruit quality. The properties of producing fruiting wood greatly determine the renewal capabilities of cultivars. Knowing these properties is essential in case of sour cherries, the fruit species that requires a lot of sunlight and tends to produce bare wood. The research of candidate cultivars until now focused on fruit quality. Our aim was to investigate the vegetative characteristics of the resistant ‘bosnyák’ cultivar group in detail, defining the growth characteristics of these cultivars.

  • Irrigation Requirements for Grape Crop under Climate Changes Conditions in Egypt
    23-27.
    Views:
    408

    The present work is mainly directed to discuss sensitivity of climate changes upon the irrigation demand for grape crop in Egypt. The Penman Monteith equation was used to calculate reference Evapotranspiration (ETo) under current and future climate for the two locations (El Menya and El Beheira). The historical climate data for ten years from (2000 – 2010) was used as current climate to calculate irrigation requirement for grape crop under Egyptian conditions. Two climate changes scenarios have been applied as changes in temperature. The first scenario supposed that increasing in temperature of 1.5°C would happen, and the second scenario supposed that increasing of 3.5°C would happen to calculate reference Evapotranspiration and irrigation requirement for future climate. The results showed that the evapotranspiration and irrigation requirement for grape crop at El Menya location higher than El Beheira location. Irrigation demand for grape plant under two climate changes scenario will increase in El Menya and El Beheira locations. El Menya location will take the highest irrigation demand under climate changes. Therefore, possible adaptation countermeasures should be developed to mitigate the negative effects of climate changes for the sustainable development of agro-ecosystems in Egypt.

  • Challenges of the vegetable and fruit market
    83-89.
    Views:
    461

    The situation of the horticulture sectors have been in the limelight of the professional and economic decision makers all over Europe. This article analyses the situation of the sector from economic point of view and reveals the main reasons of its low income and high risk. It concludes that one of the biggest problems is the trading uncertainty in the vegetable and fruit sector that is caused by the asymmetric market structure of the post-regime era. Since sizes of vegetable and fruit plantations do not allow producers to supply individually the extremely concentrated food retail trade or the processing trade they must find alternative ways for trading their products. The study introduces two alternative solutions. One alternative is foundation of modern multi-level producer co-operatives with the help of EU subsidies. Secondary and tertiary co-operatives may achieve better market position and lower trading price risk with managing production, professional marketing, and improving the information flow. The other alternative is searching for new trading channels such as local provision, restructuring of local markets, and direct trade (home delivery and pick-it-yourself programmes). The shorter producer-consumer distance means better quality at lower price for customers and income in the case of smaller amount of products for producers. It is concluded that both solutions together or separately may help individual producers in their trading problems. However, whichever way they choose, producers must co-operate.

  • The use of rootstocks for European (Prunus domestica) and for Japanese (Prunus salicina) plums (review)
    7-13.
    Views:
    882

    The worldwide tendency to increase the intensity of fruit growing technologies prefers generally for every fruit species rootstocks with week or mediocre vigour. From this viewpoint, the use of rootstocks for plums are rather unilateral in Hungary, where 95–99% of plum plantations are grafted on mirobalan seedlings (P. cerasifera v. mirobalana). The score of plum rootstocks abroad is much more diversified. The present study summarises the respective knowledge referring to the literature available.

  • Studies on some seed traits of Iris pumila L., Adonis vernalis L., Primula veris Huds. and Alkanna tinctoria (L.) Tausch.
    36-40.
    Views:
    215

    In this study we summarize the results of a five-years period concerning seed traits examinations on Iris pumila, Adonis vernalis, Primula veris and Alkanna tinctoria, with special attention to seed dimensions, seed mass and other traits concerning plant fitness, to their variability and the relationship among them. We found tight correlation between seed weight and seed dimensions in Adonis and Primula, at the same time no correlation exists among the same characters in Alkanna tinctoria. Consequently, the seed weight and seed dimensions can be used as synonyms in the form of „seed size" only after preliminary detection of correlations among them.

    The variability of seed traits is higher in natural categories (individuals, morphs) than in seed mass categories as speculative groups. When we need homogeneous plant stand (e.g. for an introduction experiment) it is suggested to use seeds pre-selected in this way. For ex situ conservation, where the central goal is to maintain the genetic variability, seeds originated from different individuals are preferred.

     

  • Reducing nitrate content in lettuce using polyolefin-coated fertilizers
    35-38.
    Views:
    198

    Pot experiments were conducted in order to investigate the effects of the controlled-release characteristic, nitrogen form and application method of polyolefin-coated fertilizers on the nitrate content and yield of lettuce (Lactuca sativa L.). Comparing broadcast application of polyolefin-coated urea (POCU) and urea at four fertilization levels, it was found that application of POCU decreased the nitrate content and increased the yield, due solely to its controlled-release characteristic. Comparing band applications of POCU or polyolefin-coated diammonium-phosphate (POC-DAP) to broadcast application of ammonium nitrate, it was found that a band application of both urea and ammonium containing polyolefin-coated fertilizers can decrease nitrate content in lettuce, without causing any significant yield decrease. This was a combined effect of the controlled-release characteristic and realized ammonium nutrition. Comparing effects of broadcast, band and spot applications of POC-DAP, it was found that nitrate content, was the lowest in the spot application treatment. However, considering both nitrate content and yield, band application was found to be the most effective application method.

     

  • Growing experiments with a medicinal mushroom Agaricus blazei (MURRILL)
    45-48.
    Views:
    361

    The demand of natural and medicinal products has been increased for the past years. These products are often made from herbal and medicinal plants, and recently the mushroom products are much called. Nearby some well known species (like Lentinula edodes or Ganoderma lucidum) some not respected biomedicines are available in Hungary. Agaricus blazei (Murrill) is a Basidiomycota fungus, with almond-like taste and nice texture. This medicinal mushroom proved to be useful in cancer therapy and against some bacterial and viral diseases. In our experiment we tested 8 Agaricus blazei strains on fermented mushroom compost. The yields, average mushroom size, productivity and biological efficiency of the species were measured. Our data demonstrate that it is possible to get fruit bodies less than 2 months, and strain "837", "2603" and "MaHe" are suggested for further experiments. These strains gave the highest yield and efficiency in the cultivation.

  • Drought stress monitoring by laboratory and satellite spectral methods in an apple orchard
    7-9.
    Views:
    408

    An orchard can be examined on the basis of spectral data, using such methods with which the reflected radiation can be divided into a large number of (several hundreds) small spectral channel (some nm). Based on the spectral characteristics of the canopy, or the different index numbers calculated from hyperspectral data the water supply conditions of foliage can be well characterized. The research site is an intensive apple orchard, which located in Debrecen University, Centre for Agricultural and Applied Economic Sciences, Farm and Regional Research Institute at Pallag. During our experiments the evaluation of spectral, non-invasive measurement method are carried out for detecting stress symptoms caused by drought. Furthermore, MODIS NDVI time series data were analyzed for orchards situated in North-Eastern part of Hungary in drought effected and wet years in order to detect differences. Significant differences in NDVI values were detected after the end of June.

  • New evaluation method to detect physiological stress in fruit trees by airborne hyperspectral image spectroscopy
    37-40.
    Views:
    349

    Nowadays airborne remote sensing data are increasingly used in precision agriculture. The fast space-time dependent localization of stresses in orchards, which allows for a more efficient application of horticultural technologies, could lead to improved sustainable precise management. The disadvantage of the near field multi and hyper spectroscopy is the spot sample taking, which can apply independently only for experimental survey in plantations. The traditional satellite images is optionally suitable for precision investigation because of the low spectral and ground resolution on field condition. The presented airborne hyperspectral image spectroscopy reduces above mentioned disadvantages and at the same time provides newer analyzing possibility to the user. In this paper we demonstrate the conditions of data base collection and some informative examination possibility. The estimating of the board band vegetation indices calculated from reflectance is well known in practice of the biomass stress examinations. In this method the N-dimension spectral data cube enables to calculate numerous special narrow band indexes and to evaluate maps. This paper aims at investigating the applied hyperspectral analysis for fruit tree stress detection. In our study, hyperspectral data were collected by an AISADUAL hyperspectral image spectroscopy system, with high (0,5-1,5 m) ground resolution. The research focused on determining of leaves condition in different fruit plantations in the peach orchard near Siófok. Moreover the spectral reflectance analyses could provide more information about plant condition due to changes in the absorption of incident light in the visible and near infrared range of the spectrum.

  • Ultrastructural and biochemical aspects of normal and hyperhydric eucalypt
    61-69.
    Views:
    440

    Hyperhydricity was observed throughout in vitro multiplication phase of a Eucalyptus grandis clone. Ultrastructural approach of tissue and cell differentiation, izoenzyme patterns, binding protein (BiP) expression, and pigment content were performed. Hyperhydric tissues showed a reduction in cell wall deposition, reduction of membranous organelles, higher cell vacuolation, and more intercellular spaces than its normal counterpart. Additionally, several vesicles were present in hyperhydric cells suggesting the occurrence of organelle autophagy by autophagic vacuole. Lower pigment content, intercellular spaces on the epidermis and the induction of a molecular chaperone (BiP) were observed in hyperhydric phenotype. Evidences of schizolysigenous process of intercellular space formation are compatible with a stress condition. Although plastoglobulli were observed in normal and hyperhydric chloroplasts, they were more evident in the normal ones. Abnormal stomata also reflected a disruptive situation and morphogenesis disturbances which would difficult plant acclimatization. Further observation of the epidermis ultrastructure allows us to conclude that the presence of intercellular spaces on its surface may be constraining the recovery and development of hyperhydric plants. Similarly to BiP, other proteins such as esterase (EST), acid phosphatase (ACP), malate dehydrogenase (MDH) and peroxidase (PDX) are possible to be used as stress markers in in vitro conditions. Our results confirm earlier findings about negative effects of hyperhydricity on in vitro plant morphogenesis and ultrastructure, which in eucalypt is associated with a stressful condition contributing to lower propagation ratios.

  • The inheritance and durability of scab resistance in apple progenies
    39-46.
    Views:
    298

    In order to select the appropriate parent cultivars and maintain the durability of resistance, it is important to clarify the mechanisms of inheritance of scab resistance depending on the parents. It has been known that the progeny segregation ratios based on scab-resistance do not depend only on the genotype of the resistance locus but also on the genetical makeup of the donor and recipient parents as well as on the susceptible parent.

    The aim of this study has been to demonstrate what factors in the Vf, Vr and VA scab-resistant cultivars — combined with susceptible and resistant parents — affect the inheritance and durability of resistance in seedlings in their first 4 year's growing four years' growth. After inoculating apple seedlings sown in 2001 with the suspension of Venturia inaequalis (Cke.) Wint. in the greenhouse, we studied the segregation ratios of the progenies into reaction classes. Seedlings showing resistance in the greenhouse were also evaluated for scab-resistance after they had been moved to the field and had naturally been infected with the pathogen in 2002 and 2004.

    The majority of our results obtained in the greenhouse test, similarly to earlier experiences, have not justified monogenic inheritance at the phenotypic level. The effect of susceptible parent cultivars on the segregation ratio of progenies have become apparent again. The high infection rate of seedlings in the field trials, which had previously exhibited varying degrees of resistance in the greenhouse test, has raised concern. Our data has raised further doubts, concerning the durability of Vf resistance in Hungary. It is assumed that the composition of natural field populations of Venturia inaequalis in Szigetcsép has changed. The complexity of Vf resistance has been confirmed. The high infection rate in the progenies derived from Vf resistant cultivars draws the attention to the importance of utilizing additional sources of resistance.

  • Study of Erwinia amylovora colonization and migration on blossoms of susceptible and tolerant apple cultivars
    15-19.
    Views:
    257

    The stigmata of detached flowers of susceptible and tolerant apple cultivars were inoculated with about 104 gfp labeled Erwinia amylovora . There were no apparent differences in the colonization, multiplication and survival of the bacteria on the stigmatic surface of the culivars. Bacteria were washed down to the hypanthium surface 24 hours after inoculation. The visual symptoms of the infection were the discoloration and shrinkage of the floral parts. The gradual browning associated with the infection appeared first on the surface of the hypanthium followed by the discoloration of the style. The color of the filaments turned into brown only 120 hours after the inoculation. Bacterial cells were not detected in the tissues of the styles and filaments. The traits of the hypanthium surface are of prominent importance in the progression of the infection. The wrinkled surface, the convex shape of the outer epidermal cell walls with thin cuticle and the sunken stomata helped to preserve a water film for a longer period providing medium for the motility of the bacteria in the susceptible cultivar. Bacteria were restricted to small water droplets on the flat and waxy surface of the hypanthium of the tolerant cultivar and only a few were able to enter the tissues.

    Large bacterium aggregations were detected in the intercellular spaces of the parenchyma of the susceptible cultivar 48 hours after the inoculation. In the next period the Erwinia amylovora cells gradually invaded the intercellulars of the hypanthium wall, the wall of the ovary and the pedicel. Low level of bacterium aggregation was found in the intercellulars of the tolerant cultivars. It is suggested that the progression of the infection was inhibited also by physiological factors.

  • Assessment of fruit firmness of pepper using non-destructive physical measurements, in response to different growing and pruning technologies
    59-62.
    Views:
    218

    The European market demands vegetable products of the highest quality and this commercial quality must be maintained till the goods reach the customer. One of these important quality parameters is the fruit firmness of pepper.

    The experiments were aimed at to find out the influence of different growing methods (soil or rockwool-based) and pruning technologies (to 1, 2, 3 or 4 shoots) on the yield and fruit firmness of three pepper varieties (HO F1, Karpia Fl and Pritavit F1) which are common in Hungary. Fruit firmness was measured by the non-destructive impact method.

    On the basis of the results, in unheated forcing the pruning to 1, 2 or 3 shoots can be suggested for all three varieties, as well as the utilisation of rockwool in their growing.

    The non-destructive impact method has been found suitable for testing the fruit firmness of pepper varieties. In the experiments involving different growing mediums pepper stands were found to show significant differences, however the different pruning methods had no significant influence on fruit firmness.

  • The effect of spring frosts on the nectar production and the bee visitation of fruit trees
    86-89.
    Views:
    702

    Fruit tree species suffered very strong spring frosts in 1997 in Hungary. This caused partial or total damages at buds and flowers depending on site and time of blooming. It was demonstrated at a number of experiments that frost and cold weather also strongly affected the nectar production of surviving flowers. No or very little amount of nectar was measured in flowers first of all of early blooming fruit tree species (apricot) but also of pear and apple in some places. In spite of this fact intensive honeybee visitation was detected in the flowers of fruit trees that suffered partial frost damage only at those sites where honeybee colonies were placed in or at the experimental plantations and the lack of sufficient amount of nectar did not affected bee behaviour seriously on fruit flowers. This means that bad nectar production failed to affect bee visitation of fruit trees definitely. The reason for this was the fact that not only fruit trees but another early bee plants (wild plants, too) suffered frost damage. Accordingly, in lack of forage bees intensively searched for food at blooming fruit trees with some living flowers. Consequently, there was an acceptable yield at those plantations where bud and flower damage was not complete. Accordingly, intensive bee visitation (that is moving additional bee colonies to overpopulate fruit orchards with honeybees) can be an effective tool to decrease or eliminate the detrimental effect of spring frost on the yield of fruit trees where bud or fruit damage is not too high.

     

  • Ecological characteristics of natural and culturated species, their comparison in Prunus genus
    7-16
    Views:
    417

    Plum species are found native throughout the nothern hemisphere, but mostly in the temperate zone. The earliest writings about plum date back some 2000 years (De Candolle, 1894; Cullinan, 1937) puts the age of plums at 2000-4000 years old (Bagenal, 1954). However, the stone core findings suggest a greater past. The question is difficult to conclude because the large number of species of the genus are taxonomically unclear and spread over a wide geographical area. The taxonomic position of stone fruit species and varieties can also be different, especially for Prunus species (Kárpáti, 1967; Terpó, 1974; Raming & Cociu, 1991; Faust & Surányi, 1997; Surányi, 2013).  The study analyzes the average relative ecological value measurement numbers of 75 species, including 120 cultivars, in terms of diversity and similarity. It is novel that, based on the sources, the author used the Ellenberg-Borhid values for the European, Asian, North American and other species, expanding them with transitional subgenera (e.g. Microcerasus). It was also possible to pay attention to a North African, Central and South American Prunus/Prunophora species. Following the accounting of economic and fruiting values, the species, subspecies, and varieties of the European and Mediterranean regions are the finalists, but species hybrid plums, rootstocks, or Prunus species whose values have not yet been known can play a role. Although the kéköny is a known species, it can become a cultivated fruit species due to the high antioxidant content of the fruit (Hegedűs & Halász, 2019).

  • Effects of initial spacing on the stand structure and yield of young black locust (Robinia pseudoacacia L.) stands
    37-39.
    Views:
    267

    The choice of the right initial spacing of stands is one of the most decisive operations of a successful afforestation. It is even more important in the case of fast growing tree species grown in plantations; it is expressed in their early phase of development and in wood quality. The results of a 5-year long experiment with four treatments will be presented in this paper. They proved the priority of an initial spacing of 1.61.0 m in the majority of quality This treatment has been proved optimal exploitation of growing space by the young trees.

  • The effect of wear of petrol engine power brush cutters on their vibration exposure
    37-44.
    Views:
    279

    The matter of noise and vibration exposure has an accentuated emphasis in the environmental protection policy of the European Union. In practice, the focus is on the evaluation of noise -strain. The evaluation on human beings' vibration-strain is in focus in recent years. At the Technical Department in Corvinus University of Budapest Faculty of Horticultural Sciences we evaluate in PhD training form the possible ways of alleviation and revealance of noise and vibration-strain in gardening devices and machineries. According to the latest development in gardening culture, small gardening machines are more and more widespread. There is a law in Hungary for the compulsory grass-cutting, especially on 'ragweed' (Ambrosia elatior). Along highways, public territories, parks workmen at least six months are in charge to terminate these weed-crops meanwhile they are endangered by serious harmful effects. The operators of hand-held power tools are exposed comprehensive levels of hand-arm vibration at the tool-hand interface. Many studies indicate that extended exposure to mechanical vibration can induce degeneration of the vascular and sensioneural systems in the hand called hand-arm vibration syndrome (HAVS). The precise mechanism for the initiation and development of HAVS is unclear to date. Measurement and risk assessment of hand-transmitted vibration is mostly based on the guidelines and dose-response relationship provided in the ISO-5349 standard. These guidelines suggest that the magnitude, frequency, direction and duration of vibration exposure are the most important variables for the risk assessment of hand-arm vibration. This current study is focusing on brush cutters owned by one of the biggest caretaker company. These machines have similar brand and age but different in usage time. We inquired seven brush cutters through two years. The manufacturer repaid the vibration level of the new machines, but they doesn't examine, whether extent of the vibration emission is changing for the proper use. We wanted to know that are there any differences between the values of vibration specification after certain time of usage. Is it possible to monitor the alternate movements on graphs according to the vibration sciences? By Ill octave band frequency and FFT analysis we can point at that these brush cutters can show differences in critical frequencies. These biases can influence the hand-arm system and its vibration-strain burdening.

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