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Distribution and damage of bacterial canker on lemon bushes in the conditions of the Southern part of Azerbaijan
41-49Views:210This paper summarises and presents the results of two-year (2020–2021) field and laboratory studies on the spread and harmfulness of bacterial canker of citrus crops (Xanthomonas citri (Hasse) Dowson.) on mid-ripening lemon cultivars (Citrus limon L.). Experimental field research conducted by us in 2020–2021. It has been established that bacterial canker (Xanthomonas citri) is found mainly on lemon bushes (Citrus limon L.). The pathogen also causes canker (Xanthomonas citri) on kinkans (Fortunella margarita (Lour) Swingle.), poncirus (Poncirus (L.) Raf.), lime (Cirtus aurantiifolia (Christm.) Swingle.). Japanese cultivars of oranges (Citrus sinensis (L.) Osbeck.) and citron (Citrus medica L.) are distinguished by significant tolerance. The most resistant are tangerines (Cirtus reticulata Blanco.) – they are almost not affected by bacterial canker (Xanthomonas citri).
We have established environmental factors that contribute to the wide spread and development of bacterial canker (Xanthomonas citri) on lemon bushes in the southern part of Azerbaijan.
The main indicators of the harmfulness of bacterial canker (Xanthomonas citri) have been identified. The potential for the death of canker-infected lemon fruits has been established. The characteristic features of external and internal signs of the disease were established. A scheme for combating bacterial canker (Xanthomonas citri) has been developed, and the optimal concentration of fungicides that retard the growth and development of pathogens has also been established. Photographs of bacterial canker (Xanthomonas citri) damage to lemon fruits are presented.
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Inhibition of the spread of Sclerotinia sclerotiorum in aquaponics
5-8Views:651Sclerotinia sclerotiorum, which causes white mold, is a widespread pathogen. In 2020, a new host plant of this fungus, the watercress (Nasturtium officinale) was identified in Hungary in an aquaponic system. During the cultivation of watercress S. sclerotiorum was detected on the plant, the fungus caused a 30% yield loss. Fungicides should not be used against fungi in aquaponic systems. Non-chemical methods of integrated pest management should be used. These include biological control (resistant species, predators, pathogens, antagonist microorganisms), manipulation of physical barriers, traps, and the physical environment. In the aquaponic system, the removal of the growing medium (expanded clay aggregate pellets) solved the damage of Sclerotinia sclerotiorum 100%. By removing the expanded clay aggregate pellets, the environmental conditions became unfavorable for the development and further spread of the S. sclerotium fungus.
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The effects of fertilization on the protein related properties of winter wheat
67-69Views:469The yield and quality of wheat are mainly determined by the plant production system, thus we studied the effect of mineral fertilization.
The field trials were set up in 1983 at the Látókép Research Institute of the University of Debrecen. We examined effect of different Nfertilizer doses (60 kg ha-1 N/P/K, 120 kg ha-1 N/P/K) on Lupus, Mv Toldi and GK Csillag's protein properties in 2012. During the tests, three quality parameters were determined: wet gluten content (%), wet gluten spread (mm/h) and gluten index (%). In the experiment the effect of different doses of N-fertilizers significantly influenced by the wet gluten content and gluten index of Lupus.
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Occurrence of woolly cupgrass (Eriochloa villosa /Thunb./ Kunth) in Hajdú-Bihar county, Hungary
119-123Views:175Woolly cupgrass (Eriochloa villosa /Thunb./ Kunth) is native to East Asia, it spreads in several parts of the World and causes difficulties in plant protection, especially in maize. Difficulties in control of Eriochloa villosa originated from several reasons: seeds continue to germinate later in the season, significant part of seeds emerges from a deep layer of the soil, and the species is less susceptible to some herbicides applied to maize than other annual grass weeds.
The first report on the occurrence of woolly cupgrass in Hungary was published in 2008, and it reported about the appearance of this species near to Gesztely village (Borsod-Abaúj-Zemplén county), however, no information has been added about spread of the weed in Hungary until now.
A significant population was discovered next to Debrecen (Hajdú-Bihar county) in summer, 2011, and then weed associations were examined in maize, sunflower and stubble-fields on several km2 in the area to estimate the Eriochloa villosa infection. The weed species was found on every maize field bordering with a ground cover of 0.5-4%. Woolly cupgrass occurred inside of the 50% of maize fields, and reached a ground cover of 76% in case of most infected area, in addition it was found in sunflower and stubble-fields.
The spread of woolly cupgrass is expected in this area, which requires the consideration of this species in the planning of weed management technologies. -
Examination of the American grapevine leafhopper (Scaphoideus titanus Ball) in Debrecen and Micske (Misca, West Romania)
77-81Views:366Grapevine flavescence dorée (FD) was detected first in Hungary in 2013 in Zala County (South-West-Hungary). The disease is a serious danger for grapevine growing and grapevine propagating production. In 2014, the pathogen has been found in several new places in Hungary, viz. in Vas and Fejér Counties, and it was also detected in the former location in Zala County. The american grapevine leafhopper (Scaphoideus titanus) is the main vector of the disease. This pest was detected first in Hungary in 2006 and then it has spread all over the country. Since we have not detailed distribution data of this pest in surroundings of Debrecen, therefore we made observations in this region in 2014. The presence of the pest was confirmed by yellow sticky cards in two locations in Debrecen and another site in West Romania near to Hungarian border. We found that S. titanus is present in each sampled sites that cause serious potential danger for the appearance and spread of Grapevine flavescence dorée (FD) in this region.
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The distribution of brown marmorated stink bug (Halyomorpha halys (Stål, 1855); Hemiptera: Pentatomidae) in the Northeast part of the Carpathian Lowland (West Ukraine)
191-194Views:452Halyomorpha halys (Stål, 1855) spread rapidly during the last five years and became common and abundant in Central Europe, especially in the urban environment. In the Carpathian basin, the West Ukrainian Transcarpathia county was the last region where this species has not been found yet. The first specimens of this invasive pest were sampled in Velyka Dobron’ in 2018 and in 2019 it was found in another neighbouring village and cities of Chop, Berehove and Uzhhorod. The data provided here is the first for West Ukraine and the second for the country following the published record from Odessa (SE Ukraine). Although H. halys is still less abundant and occupied mainly urban habitats, it will certainly cause nuisance for peoples and damages for farmers in the near future.
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Energy crops on less favoured (alkaline) soil
115-118Views:247The reduction in fossil energy and row material sources induces growing demand for renewable resources. The growing demand for herbal raw materials has land use impacts as well. One way to reduce the conflict between the food and energy crops can be the utilization of less favored areas by growing energy crops. Among the potentially available areas for this purpose the salt affected soils (SAS) occupy a significant territories. SAS with structural B-horizon (meadow solonetz soils) represent the most wide spread group of SAS in Hungary. About half of these soils have been reclaimed and used as arable land and the remaining 50% are used as grassland. Sweet sorghum production for manufacturing of alcohol production was investigated in a long term amelioration and fertilization experiment on a salt affected soil (meadow solonetz). By means of regression analyzes the effect of sodium content of the soil and increasing mineral fertilizer doses were studied. According to the multiple regression analysis only the effect of nitrogen fertilizer was significant. On the solonetz type salt affected soil the effect of water soluble salt content of the soil was not significant, but there was a closer correlation between the ammonium-lactate sodium content and the yield of sweet sorghum. The maximum green mass was 45–50 t ha-1, in the case of low Na content and high level of nitrogen fertilization.
In order to quantify the potential yield of natural grass vegetation the relationship between the soil forming processes and the grass vegetation
was investigated. Beyond the different forms of Na-accumulation, the spatial pattern (mosaic-like characteristic) is also an inseparable feature of salt affected soils. The difference in the water regime, caused by the micro-relief is the main cause of variability. The run-on water keeps the deeper parts of the catena position wet longer. The wet situation causes more intensive leaching. In the low-laying parts of salt affected soils species preferring wet situations (mainly Alopecurus pratensis) are in majority. On the higher parts of the micro-relief species tolerating dry situations (mainly Festuca pseudovina) are dominant. The yearly grass production of low laying areas can be 4–7 t ha-1 but because of prolonged wet conditions the grass is not grazed and mowing can only be in old state. This old grass is not proper for feeding, but it may be suitable as energy plant. -
Nyelvi kompetencia-elvárások a multikulturális munkaerő piacon
11-14Views:282Proficiency in a foreign language, especially when combined with knowledge of and skills in another professional area, is highly desirable in the multicultural marketplace. Just as business and media have experienced global changes over the last few decades, so, too, has grown the acceptence of English around the world as the lingua franca for economic and scientific exchange. Second language speakers increasingly turn to English as a requirement of international communication. It is more than understandable that in many European companies, proficiency in English may even be a hiring criterion (Inman, 1983). The spread of English thus privileges certain groups of people and may harm others who have less opportunity to learn it.
One can rightly conclude that we are in an age when communicative language skills in English are an indispensible component of literacy. Many claim that this may well entail significant changes in the social and individual values of nations and people.
This paper investigates some of those underlying social and economic processes that have over the past few decades brought English language literacy into the focus of the attention of many researchers and educators. In the framework of the paper, certain issues of the conceptual impact that these changes have (or are presumed to have) on English language education are also discussed. -
Rippl-Rónai’s color in the native parks: production and using of new, synthetic Wild sage color-mixture
59-64Views:346The climate changes is becoming more damaging to ornamental plants. Besides ornamental species and varieties of plants on public spaces. It will be necessary to use domestic, well adaptable climate-tolerant plant species.
One field of our growing ornamental plants researches from 2001 in the Centre of Agricultural Sciences of University of Debrecen, is studying drought patient, mainly Hungarian improved annual varieties, which are able to get acclimatized with the landscape. Moreover, we have in view to work out new, economical seedling production technologies. In the program, the excellent drought- and frost tolerant annuals and perennials belongs to the climate change tolerant plants. From the evaluated of species we want to create and spread the application. of the new types of ornamental horticulture culture.
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Tenability of ram semen
63-66Views:533It could be stated that the diluted semen of Awassi rams taken in the breeding season preserved its fertilizing abilityat different temperatures for different periods of time. The motility of spermatozoa kept at 23 vs. 8oC was checked daily. The largest spread of data was observed 24 hours after taking the semen, then the motility rate of cells showed a linear decrease. Motility results of fresh and frozen-thawed samples were compared also after heat resistance test and significant differences were found between these groups. Significant individual differences were observedin the sperm motility after heat resistance test.
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60th Anniversary of Hungarian Plant Protection Service
8-10Views:212The author briefly overview the history of the 60-year-old Hungarian Plant Protection Service, which has improved to a model by its ’golden age’ period with a well organized system and excellence of specialists on the chemistry period of Hungarian agriculture. The profound changes both in policy and economy resulted a serious structural changes which continue even nowadays. Meanwhile country borders have been opened than EU membership of Hungary have generated new challenges by appearance and spread of new pests.
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Status and Prospects of Integrated Pest Management in Apple Production in Hungary
307-316Views:203Farming methods supporting the ecological function of agriculture will play an even more dominant role in the near future than they do now, as much in Hungary as in the rest of the EU.
Several farming techniques supporting sustainable development have already evolved, and in this essay, I deal with integrated production i.e. integrated fruit production in Hungary and its perspectives. I analyze both European and Hungarian regulations on integrated production and their development.
It is obvious that in the orchards of Europe, integrated production is gaining ground. We can expect the increased spread of this western trend to Hungary, too, because one of the conditions for remaining on the market will be a product from integrated production. However, we cannot expect any rapid increase in the future. In my opinion, there are three ways to propagate integrated production:
− changes in the approach of farmers;
− vocational training of farmers because of the greater „knowledge-demand”; improving the consultant network;
− strict monitoring of the production process. -
Characteristics of roe deer bot fly infection in the southern part of the Great Hungarian Plain
57-60Views:299I am investigating the occurance of one of the diseases caused by parasites in plain roe deer populations, namely a botfly larvae, Cephenemyiastimulator, (Clark, 1815) ranged among the Oestridae family. Nasal botfly larvae are common roe deer parasites and are generally spread nationwide. The subject of the present survey is the processing of the data gained about roe deer bucks of the year 2009 and their infestation indices. I investigated botfly larvae in 90 bucks’ nasal and pharyngeal cavity. We have found botfly larva in 18.9% of the examined bucks (prevalence), this means 17 infected specimen. I collected 218 pieces of larvae from the samples, with a 12.8 pieces average intensity. In my investigations prevalence was lower and mean intensity was higher than in previous Hungarian researches. This was manifested both in my overall data, and in our examinations by the different age groups.
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The Present and Future of Tokay Aszú
87-92Views:210Tokay wine is Hungary’s noblest wine. Beyond doubt, it is one of those uniquely Hungarian products, which has been without rival for centuries. Today the role of quality has become increasingly important and consumers who are ready to pay more for quality wines expect it. This wine will be able to get back its original popularity if the message of its excellence reaches the public. Knowledge of historical wine-producing regions constitutes a part of basic education and wine-marketing could take important measures to spread it since good products need to be sold properly and consumers require information about wines – with gastronomy – and wine producing regions.
With foreign invested capital, advantageous changes have been started in Tokay-Hegyalja. However, there is much still to do in order to produce, sell and consume Tokay wine on such conditions that are really worthy of a Hungaricum. It is essential to approach the famous oenologists of Europe and the world and to establish suitable production conditions for every winegrower. In addition to following consciously prepared wine-marketing directions, our country needs to make an expected name for this Hungaricum. These aims are important mainly because of approaching EU-accession. There is timely to study on what conditions Hungarian viticulture and oenology could access. It would be a great success of the Hungarian delegation if they could make current Hungarian laws of Tokay-wine-production accepted in the EU. Of course, all of these would be valid after EU-accession. During the pre-accession period, our country needs to fulfil several stipulations. For example, origin-protection, establishment of a registry system, law harmonisation, development of an institutional system.
Strengthening of home consumption has always been an inspirational tool in a product’s life cycle. It is important not only to take the requirements of foreigners into consideration and to produce for export, but we also need to satisfy the home market. Considerable stress should be laid on establishing and preserving viticulture. Increasingly, buyers expect high standards and they are ready to pay more for quality wines. They also demand appropriate professional information and consultation. So there is a lot to do and theoretical approach should be followed by action. In order to get to know what quality expectations exist, we have to examine the consumers of the Hungarian wine-market. Study of the Hungarian people’s consumption behaviour, referring to Tokay „aszú”, was closely connected with my work.
Participants of my study were consumers who buy Tokay „aszú” mainly in shopping centres, supermarkets and low-price shops specified for wine selling. Wine shops have important roles as they give opportunity for salespersons to make closer relationships with buyers. These shops could be communication channels of spreading wine culture. It would be favourable if in every town or city there were at least one wine shop giving the opportunity of consultation besides commercial activity and also providing services that support the improvement of wine culture’s position. The majority of questioned people spend less than 4.000 Forints on buying of Tokay „aszú” in a year. Results of the questionnaire survey support the fact that there is a demand for these wine-specialities, but lack of money strongly effects demand.
The Following summarises the history of Tokay wine, tasks of Hungary and the expected effects relating to EU-accession. Regulation of oenology and the wine-market, referring to quality wines and main results of the survey are also overviewed in the text. -
Host plant preference of Metcalfa pruinosa (Say, 1830) (Hemiptera: Flatidae) in the north of Hungary
84-95Views:472Citrus flatid planthopper, a native insect to North America had for a long time a scarce economic importance there. However, being polyphagous made little damage on citrus trees and some ornamentals. In 1979 it was introduced to Italy where it established and spread quickly. It is now an invasive alien species continually spreading in South and Central Europe causing considerable damage in fruit crops and various ornamentals. Present study shows the results of a series of observations carried out from 2011 to 2015 at a number of habitats in north of Hungary. The pest could be found at each habitat but the hedge, the tree row, the gardens and the orchard/vineyard were the most infested. Frequency and population density of Metcalfa pruinosa were considerable on Asteraceae, Cannabaceae, Fabaceae, Juglandaceae, Lamiaceae, Rosaceae and Sapindaceae. Typical vegetation could be functionally classified as ornamental plants, trees/shrubs, fruit plants, weeds and feral plants. Feral plants – some of them also invasive alien species – were found at each habitat. Plant species native to America were among them the most populated. As the hedgerows were neglected, and most gardens, orchards and vineyards abandoned, these are excellent conditions for the quick and long-lasting establishment of the pest as well as they may be reservoirs to infest cultivated fruit crops and ornamentals. The hedgerow was situated along a railway line. The length of similar hedges can be merely in Pest county several hundred km, which means M. pruinosa has plenty of opportunity for spreading along the railway and infest agricultural and ornamental cultures. On the surveyed alfalfa and maize fields, accidentally very few nymphs and adults were observed. Although, the population density of M. pruinosa was considerable on many hostplants, economic damage or yield losses could not be detected. Economic or significant damage was observed only on roses, raspberries and stinging nettle. This later is cultivated in Germany and Finland. The applied horticultural oil was efficient.
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The egg production of hungarian speckled hen and speckled transylvanian naked neck hen
11-15Views:174Our Faculty has been dealing with the cross-breeding of Hungarian speckled hen to maintain the breed since 1977. We keep two breeds of the Hungarian speckled hen, the bare-neck variant and the feathered-neck type on the pilot farm. Because of the spread of intensive poultry keeping the population of these breeds has become endangered. Beside the gene preservation, we endeavour to find the best way for the production-purpose
utilisation of the speckled hen stock. We examined the egg production of these breeds. -
Overview of the evolutionary history and the role in citric acid production of alternative oxidase
83-88Views:281All organisms are exposed to countless environmental effects, which influence in a disadvantageous way their life processes. They continuously adapt to the changing conditions and respond to the stress impacts by defence mechanisms. Through different signal transduction pathways they are able to increase or decrease the expression of their genes and consequently modify their metabolic processes. My interest focuses on alternative oxidase (AOX) enzyme whose expression is often increased under biotic and abiotic stress. The so far proven and putative functions of the AOX play a role in the ability of organisms to adapt to different conditions, such as heavy metals accumulation, pathogenic infection, oxidative stress and lack of oxygen or nutrients.
AOX is a member of the di-iron carboxylate protein family. Members of the di-iron carboxylate protein family are present in all kingdoms of life. They are considered to have ancient origin. It is believed that their sulfide-resistant and oxygen-reducing ability played a role in the survival of organisms during the transition between the anaerobic and the aerobic world. It is assumed that the AOX arose in eukaryotes through a primary endosymbiotic event, and this event made possible the development of mitochondria. Afterwords, vertical inheritance, and secondary and tertiary endosimbiotic events led to its spread among eukaryotes. It is assumed that bacteria obtained AOX by horizontal gene transfer from plants.
AOX-catalyzed alternative respiration plays an important role in the operation of energy-producing and biosynthesizing system of microorganisms. In these cases, the regeneration of reduced cofactors is an essential condition, and therefore may be rate-limiting for biotechnological processes, including the citric acid production.
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Self Pollination and Fruit Quality-Comparative Research of Sweet Cherry Cultivars
295-299Views:253In fruit production – among stone fruits – sweet cherry is considered to have great promise, but species of sweet cherry need improvement. Cherry plantations are advanced in years, therefore putting into operation high productivity plantations is an important field of research. Through clonal selection and cross-breeding, several new cherry species were created in the recent past in Hungary. Spread of these species is also important. In our factorial cherry production, we use high trunk trees and trees with large crowns. Intensive plantations are very few in number.
Our goal is to study the morphological and physiological properties of new sweet cherry cultivars. The most important aim is to combine the productive area of foliage and the fruit quality. The present study shows the self pollination, fruit setting and fruit quality parameters. -
e-services for the farmers
11-19Views:194Nowadays the different IT tools and use of the internet have appeared almost in every sectors of the economy, so it may give several benefits and help to the agricultural producers. In this article I give a brief overview about e-government and its’ opportunities, then I give a short description of a few important governmental and specialized administration on-line services which are provided to the farmers. According to many experts using of informatics may cause essential change in the operation of the administration because of the fact that the electronic administration may evolve. Generally speaking, today the egovernment services are already an indispensable device to the reformation of the public administration, the modification of services which suits to people's demands and the creation of the more adaptable, clearer public administration. The electronic
documents are free from formal errors which is either important for clients or offices. The cases can be arranged even from home in 24 hours of the day. The spread and success of the use of electronic services depend not only on the quality of services, but the IT readiness of the target audience is also very important factor. Unfortunately the affect of e-gap is bigger in case of the farmers. -
The Developmental Possibilities for Methods of Real Estate and Farm Property Evaluation in Agriculture
241-247Views:186Different methods for evaluating property have gained greater importance in agriculture since the change of regime. The open market evaluation could be the best method if the agricultural property had significant turnover, which could serve as a reliable comparison. However, there is no notable turnover, and selling is scarce. And, when there is some, the sales contracts are not available. On the other hand, the open market evaluation is almost the only one assessing method in Western Europe and in the United States. The matrix comparing market data in my methodological development helps to estimate the effects of the elements which determinate real estate value of farms.
Another method for evaluating farm property is the discounted future earnings. Enterprises are able to produce series of income continuously during their working periods, which can be considered as perpetuity. This is the base of the discounted future earning evaluation. Determination of income generating capacity is not an easy task. It is also difficult to choose the proper rate of capitalization. If this rate is higher than the usual level, the property will be underestimated. If it is lower, the property will be overrated. According to my calculations the profitability of certain farms of animal breeding may be evaluated under different operating conditions. Furthermore, the capitalisation interest rate may be determined in an objective way.
The problem of applying the depreciated replacement cost evaluation method is that there are big deviations among investment costs in tenders of contractors; moreover the estimations of special depreciation forms are rather subjective. One of the process’s greatest difficulties for reliability is that it is doubtful whether depreciated replacement cost could reach the real market value. The utilisation of this method may be spread further in the future by standardising average gross replacement cost of building as well as by measuring depreciation more objectively. -
Testing of paraffin oil efficiency against grape powdery mildew in Eger wine region
73-80Views:575The aim of the present study was to examine the efficiency of paraffin oil against powdery mildew in Eger wine region. The experiment has been carried out in 2013 and 2014 with Chardonnay and Kékfrankos grape varieties, which have different resistance against powdery mildew. The effectiveness of the oil was examined on leaves and clusters (frequency and intensity). This oil was effective against Erysiphe necator infection on field trials in Chile and Brazil. The spread of downy mildew (Plasmopara viticola) was also inhibited by this material in some experiments conducted in Spain and France.
The differences between oil treatments represented the sensitivity of the grape varieties in accordance with the applied dosages. The oil was effective against powdery mildew with different extent as a result of the so called ”vintage effect”. In 2013, the treatment of the highest dosage (D3) didn’t differed significantly in frequency and intensity of infection from the regular treatment (clusters of Kékfrankos, leaves of Chardonnay). In 2014, the oil was not so effective against powdery mildew compared to 2013. No remarkable differences were detected between the treatments due to the strong pressure of powdery mildew. Furthermore, no any effect of the lowest dosage (D1) was detected in the case of the sensitive clusters of Chardonnay and leaves of Kékfrankos in both experimental years.
In summary, the oil treatment has an effect against powdery mildew, however this efficiency largely depends on the vintage characteristics and the pressure of powdery mildew. Further investigations are neccessary, for example field trials with combinations of other sprays. The oil can be useable as fungicide with proper care in eco-friendly integrated and bio (ecological) viticulture.
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The effect of different compost rates on the yield of ryegrass (Lolium perenne L.)
95-98Views:300Protection of natural resources and sustainable natural resources management are essential for the long-term survival of humanity. This makes necessary nowadays the development of environmentally conscious living and spread of that in the future. The amount of organic waste materials, produced during human activities, could be decreased by composting instead of dispose them in landfills. Applying appropriate treatment technology and additives, the compost could be used as fertilizer for horticultural crops and it could increase the easily available nutrient content of soils. Compost utilization prevents nutrient deficiencies and by using the optimal rate, we could reach significant yield increases.
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The influence of the fertilizing system on the petroleum residues biodegradation on a preluvosoil under control polluted
251-254Views:209The paper presents the partial results of researches regarding the agrochemical melioration of soils under control polluted by petroleum residues that took place at the Agricultural and Research and Development Station in Oradea, Bihor County.
The experimental device was made out of 1 m2 microparcels, spread out in subdivided parcels, in four repetitions, having tree factors: A - the pollution by crude oil from Suplacu de Barcău, B – the mineral fertilization, and C – the organic fertilization.
The experience was set out on a preluvosoil în the year 1993 and the soil was cultivated with millet in the first 3 years and with spring wheat in the last 7 years of research.
The researches carried out in Oradea had the objective of establishing the effects of the fertilizing system on the petroleum residue biodegradation on a preluvosoil under control polluted with crude oil from Suplacu de Barcău, Bihor County. -
Energy Use of Biomass
264-272Views:217In this study, energy utilization of biomass is introduced with a short description of renewable energy sources and utilization possibilities of biomass.
Presently, the necessity of renewable energy sources is increasingly obvious. Among renewables, energy from biomass is to be highlighted, since this allows versatile, cheap utilization of the sun’s energy. In this respect, Hungary has advantages. Direct heat utilization and biogas production are available procedures today, whereas biodiesel and bioethanol are expected to spread in the near future. Biogas production is possibly the most versatile method for biomass conversion: it can produce energy from materials inapplicable for other utilization; at the same time, it is capable of neutralizing harmful wastes; in the end, it produces also valuable fermentative products, from bio-manure useful in agriculture, to pharmaceutical raw materials. -
75 years of the chestnut blight fungus Cryphonectria parasitica (Murr.) Barr in Europe
82-85Views:494The chestnut blight fungus Cryphonectria parasitica is a native pathogen in East Asia and has been introduced into North America and Europe. Historical records and population genetic studies revealed at least three major introduction events from Asia into Europe.
Nowadays, chestnut blight is present in almost the entire distribution range of European chestnut, i.e. from the Iberian Peninsula to the Caucasus. The C. parasitica population in most countries has been studied in respect to the diversity of vegetative compatibility (vc) types and the occurrence of hypovirulence. The vc type diversity of the different populations varied considerably. Typically, a high diversity of vc types has been found in areas with a long history of chestnut blight and where sexual recombination between divergent genotypes commonly has occurred. On the other hand, newly established populations often showed a low diversity with only one, or a few vc types present.
Hypovirulence, i.e. the occurrence of C. parasitica isolates infected by Cryphonectria hypovirus 1 has been found widespread in Europe. Natural dissemination and active biological control applications have lead to a high prevalence of the hypovirus and to the recovery of many chestnut stands. Virulent cankers became hypovirus-infected within a short time and ceased expansion. There is concern that the diversity of vegetative compatibility types could increase in Europe through sexual reproduction between C. parasitica genotypes originating from different introductions. A higher level of vegetative incompatibility would not only hamper hypovirus spread within a population but could also select for lower virulence in CHV-1 and subsequently lead to an erosion of biological control. Recent studies, however, indicate that the vc type barriers are not so restrictive than previously assumed and that so far no evidence for an erosion of biological control system in high diversity populations can be observed.