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Composition and role of hoverfly (Diptera: Syrphidae) communities in an organic apple orchard
57-61Views:90The use of hoverfly (Syrphidae) larvae in biological control is gaining more attention where the damage by their prey, aphids is significant, especially in agricultural fields and orchards, where they lower the number of aphids. The present study focuses on one hand on faunistics, on the other hand on testing the different available collecting methods for later research. Collecting in an organic apple orchard near Debrecen yielded 525 specimens of Syrphidae mostly by netting but also with white tray traps. Collected species are differentiated according to their feeding (94.1% aphidophagous). The three species found in greatest numbers are Sphaerophoria scripta (Linnaeus, 1758), Melanostoma mellinum (Linnaeus, 1758) and Episyrphus balteatus (De Geer, 1776). The available information on their biology is reviewed and their potential value of hoverflies in biological control is discussed.
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The dynamics of biodiversity structure of soil microorganisms under the impact of biopreparations during potato growing season
67-74Views:147The use of biological preparations such as Phytotsid and Planryz contributes the increase of the general number of soil bacteria population by 13.0–36.1% in the case of potato variety Scarbnytsya and by 4.5–24.6% for potato variety Oberig compared with control. It also increases the number of saprophyte microflora, which compete with plant pathogens, micromycetes, and causes 1.2–1.8 times reduction in the number of soil fungi – Fusarium and Alternaria. During the application of Rovral Akvaflo the Shannon ecological index of species biodiversity is lower than during the biopreparation use. The decrease of species biodiversity was observed as well as strengthening the dominance of some species (dark pigmentation in fungi).
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Regulation in Hungary of the Use of Waste Water and Sewage Sludge in Agriculture
143-149Views:115Regulating the use of waste water and sewage sludge in agriculture in such a way as to prevent harmful effects on soil, vegetation, animals and man.
In European Union there is a Council Directive (86/278/EEC) on the protection of the environment, and in particular of the soil, when sewage sludge is used in agriculture.
In the enlargement process of the European Union the Hungarian Government created a new rule (50/2001. (IV. 3.) Government regulation) which regulate using of waste water and sewage sludge in agriculture. This Hungarian rule is legal and reconcilable with the Council Directive.
The Regulation lays down limit values for concentrations of heavy metals in the soil, in waste water, in sludge and for the maximum annual quantities of heavy metals which may be introduced into the soil.
Waste water, sludge and soil on which it is used must be sampled and analysed.
Sewage sludge must be treated for six months before being used in agriculture.
The use of waste water and sludge prohibited on grassland, on nature reserved areas, in ecological farming, and soil in witch fruit and vegetable crops are growing, with the exception of fruit trees.
The states soil conservation authority must keep records registering the following:
– the quantities of waste water and sludge produced;
– the composition and properties of sludge;
– the type of treatment carried out;
– the names and addresses of the recipients of the sludge and places where the sludge is to be used.
The Government every four years must prepare a consolidated report on the use of sludge in agriculture, specifying quantities used, criteria followed and any difficulties encountered. This report must be forwarded to the Commission.
Last but not least in the light of Member States reports, the Commission will if necessary submit appropriate proposals for increased protection of the soil and the environment. -
Interpretation of the multifunctional agriculture’s function in regional dimensions
177-181Views:107Many branches of science have been examining the concept of multifunctional agriculture. Different interpretations have come into being on global and regional dimensions as well. This study deals with certain interpretations of the concept of multifunctional agriculture. It compares the concepts about multifunctional agriculture of the United States, the Cairns-group, the least developed countries (the LDC-s), as well as the developed countries which import food (the G10), the concept of the EU and Hungary too. It states that the different approaches to the concept have been started by the agricultural problems which are typical of certain areas. These problems have been formed in each and every area by the threefold functions (economic, social and ecological), which are characteristics of rural areas.
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Data on the bumblebee assemblages (Apidae: Bombus spp.) lives in lands under agri-environment commitment
31-35Views:213The goal of agri-environmental schemes (AES) and greening programs are protecting and increasing biodiversity in agricultural lands. The evaluation of effectiveness of AES needs further investigations. For the purpose of investigations, species and species groups should be selected which can indicate the effects of changes in landscape use on biodiversity. Bumblebees are good indicators for this purpose.
The role of bumblebees in pollination is well studied but in the case of different crops, much less detailed data are available. In 2018, bumblebee assemblages of 44 sites belonged to 8 different agricultural and semi-natural habitat types were studied in the surroundings of Sajószöged, Tiszaújváros and Derecske.
This study provides new distribution data of 8 bumblebee species in three 10×10 km UTM cells covering the sampling area. According to our results, the alfalfa and red clover fields and semi-natural grasslands has more species rich and abundant bumblebee assemblages than different crop fields (sunflower, oilseed radish and vegetable morrow) and can help protect bumblebee assemblages of agricultural lands. Based on the collected distribution and abundance data, the role of the bumblebees in pollination of the studied crops should be re-evaluated.
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Recent data about the fish consumption of great Cormorant in the area of Hortobágy Fish Farm Co
75-80Views:217The cormorant (Phalacrocorax carbo) is a bird species that nests sporadically but in colonies, besides larger fishponds and rivers in Hungary. The number of its individuals has been increasing during the last two decades. The species eats solely fish, therefore it can cause serious depredation of the fish stocks in fishponds of intensive system and after the freezing of the ponds, in larger rivers, which are not yet frozen. The aim of our research was to reveal the damages the birds can cause on the studied areas and the extent of the losses the Hortobágy Fish Farm Co. has to realize.
Our studies were carried out between April 2012 and November 2014. During cleaning, the investigation of the craw contents of the birds and their biometric studies were conducted. The results revealed the diverse food base of the species. In the samples, we have determined 379 fish individuals; in 368 cases, the exact fish species were determined, too. Significant differences were found between the consumed fish species rations of the units (P=0.05% beside). We have also found significant difference in the fish consumptions of adult males and females.
Under the ever harder fish production conditions, the presence and thus the permanent predation of the birds affect the fishermen. In favour of maintaining ecological balance as well as to hold the income of the fish farmers, elaboration of adequate protective and preventive methods will be needed in near future.
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Economic Aspects of Rural Tourism
55-71Views:72necessary to ensure the livelihoods of those leaving the agricultural sector and to supplement the incomes of those working in agriculture. I research rural development in four settlements in Hajdú-Bihar County, in Balmazújváros, Hortobágy, Tiszacsege and Egyek, all bordering Hortobágy National Park.
There are many alternative income sources in settlements in the Hortobágy area, such as organic farming, production herbs, hungaricums, small animals and arts and crafts, as well as rural tourism. Rural tourism is not for subsistence, but a supplementary income source, mainly available during the summer time. I made a survey of rural hosts in the four examined settlements, and according to my results, I constructed a model reflecting the cost-benefit relation, as well as the payment period conditions of rural tourism. I am going to show whether it is worth dealing with rural tourism, and if yes, under what conditions. Rural tourism contributes to the maintenance of rural modes of living, in this way it has significant cultural, economic, ecological and social aspects, as well. It is crucial for settlements to create the appropriate conditions needed for joining rural tourism, if it is worth joining at all, and to realise investments for all these. Rural tourism has strict requirements for the levels of environment, infrastructure and services. Studying the Western-European practices, Hungary is lagged behind in the conditions of rural tourism and rural hosts have done their activities mainly out of necessity and not to maintain traditions. Rural tourism may result in success only by co-operation and over the long-run. -
Investigation of the effects of biggame-preserves on forests with different species composition
21-24Views:144Hungary is well known for its high level game management. In order to develop a concentrated and more profitable gamemanagement new game preserves were established in the last few years. According to the law, in the game-preserves the game bearing capacity is not the most important parameter, because in these areas the feeding is continuous. In practice it means that in gamepreserves we find a much higher density of games than in nature. This causes a relative big loading of the area (of the herbaceous and arboreal), where the game-preserves are located.
Our aim is to study the ecological and management issues of forest- and game resources. The scene of these work is a gamepreserves related to the Nyírerdő Corporation (Nyíregyháza). We made forest structure survey to determine the main stand-forming tree species in the area of the game preserves as well as to estimate the number of the measuring points. -
Challenges and agroecological approaches in crop production
75-89Views:169Never has the need been greater for an ecosystem approach to agriculture. As our global population exceeds 9 billion in the next 30 years, with a concomitant demand for agricultural products, ever more pressure will be placed on our agricultural systems. Meanwhile, climate change is altering the ecological settings in which agriculture is practiced, demanding adaptation. Knowledge generated by long-term research will help to address one of the grand challenges of our time: how to meet sustainably the growing world demand for agricultural products – in a way that minimizes environmental harm and enhances the delivery of a diverse array of ecosystem services.
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Examination of nutrient leaching dynamics of Solidago virgaurea in Hévíz Lake and Hévíz canal
207-211Views:109The different nitrogen and phosphorus elements are prime constituents of the ecosystem and can exert a major effect on aquatic species and the overall ecological cycle. During our investigation we examined the nutrient leaching dynamics in decomposing leaf litter (stem and leaf blades) of Solidago virgaurea. We chose four different sampling sites during the winter period with different water temperatures in the Hévíz Lake and Hévíz canal. The bottles containing the plant material and water were incubated at natural temperatures and the fluid was removed at particular times. Water parameters such as pH level, conductivity, nutrients (ammonium and phosphates) were measured. In the case of Solidago leaf, we obtained higher values for all parameters compared to the stem ones.
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The Effect of Year and Irrigation on the Yield Quantity and Quality of the Potato
12-16Views:101In Hungary, the growing area of potato area reduced dramatically in the last few decades, additionally we are lagging behind the Western European countries as regards yields and the competitiveness of production is further decreased by the great alternation in yields from year to year, the unpredictable market conditions, bad consumption habits and many times unfortunately the lack of quality products.
The ecological and climatic conditions of Hungary are not everywhere suitable for potato, in the area of Debrecen the amount of rainfall was lower, and the monthly average temperature was higher than the requirement of potato in its growing season in 2002 and 2003.
The experiment was carried out at the experimental site of the University of Debrecen, Farm and Regional Research Institute, at Látókép. In our experiment we examined the yield and some quality parameters of 8 and 9 medium-early varieties in large parcels in 2002 and 2003 respectively. Out of the examined varieties 3 are of Dutch, and 6 are of Hungarian breeding.
The experiment was set up on 49.5 m2 parcels on calcareous chernozem soil after winter wheat as a forecrop in both years. The 9 varieties were examined in 4 repetitions in randomized blocks, out of which two repetitions were irrigated, and two were non-irrigated.
We examined the yields of the varieties, the distribution of tubers according to size and their percentages, and the changes in specific parameters of quality and inner content due to irrigation. We studied the dry matter content, the starch content, the under-water mass, the amount of reducing sugars, the colour index of frying and the element contents of tubers.
Summing up, it can be stated that among the agrotechnical year effect, variety and irrigation factors have considerable impact on potato yield quality and quantity. On the basis of our results, it can be stated that in potato production variety should be chosen in accordance with the aim of production and technology should be adapted to that specific variety. -
Fish consumption of the great cormorant in the area of Hortobágy Fish Farm
81-84Views:133The cormorant (Phalacrocorax carbo) is a bird species that nests sporadically but in colonies, besides larger fishponds and rivers in Hungary. The number of its individuals has been increasing during the last two decades. The species eats solely fish, therefore it can cause serious depredation of the fish stocks in fishponds of intensive system and after the freezing of the ponds, in larger rivers, which are not yet frozen. The aim of our research is to reveal the damages the birds can cause on the studied areas and the extent of the losses the Hortobágy Fish Farm Co. has to realize.
Our studies were carried out between April 2012 and November 2013. During cleaning, the investigation of the crop contents of the birds and their biometric studies were conducted. The results revealed the diverse nutrition base of the species. In the samples, we have determined 300 identified fish individuals; in 289 cases, the exact fish species were determined, too. Although statistical differences were found between the given pond unit and the consuming of the corresponding fish species (P=0.05% beside), this cannot be considered as absolutely certain.
Our investigation is of considerable significance in terms of nature preservation and not least, it has substantial financial concerns too. Under the ever harder fish production conditions, the presence and thus the permanent nutrition of the bird affect the fishermen. In favour of the maintaining of the natural ecological balance and the income of the fishers, the elaboration of adequate protective and efficient preventive processes will be necessary in the near future.
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Influence of phytophagous mammals environment-forming activity on the soil invertase fermentative activity in conditions of mining impact region
127-130Views:101Excretorial and fossorial activity of mammals is an important part of environment-forming activity. Mammals have influences on important biogeocenotic processes, especially on the soil processes. Determination the maintenance of soil invertase as one of diagnostic description the ecological state allowed defining limits of oscillation index in dump areas and in clean (control) native areas. The obtained results of the investigation indicate the soil depth, duration of experiment and type of area influence on soil invertase activity with the high statistical level of significance. Positive influence is revealed on invertase activity changing on dump areas, where an active excretorial and fossorial activity of phytophagous mammals was observed.
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Testing of paraffin oil efficiency against grape powdery mildew in Eger wine region
73-80Views:397The 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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A partial botanical survey of a gamepreserve
27-30Views:216Hungary is internationally well known for its high level game management. An important part of game management is indoor game keeping. In Hungary more and more game preserves were founded all over the country. The role of these game preserves to retain forest stands outside of the closed area. According to the law, in the game-preserves the game bearing capacity is not the most important parameter, because in these areas the feeding is continuous. In practice it means that in game-preserves we find a much higher density of games than in nature. This causes a relative big loading of the area (of the herbaceous and arboreal), where the game-preserves are located. Our aim is to study the ecological and management issues of forest- and game resources. The scene of these work is a game-preserve related to the Nyírerdő Corporation (Nyíregyháza).
We have done a botanical survey (plant coverage, life-form spectrum) in the three previous units and in the control area (outside of the game-preserve) as well. Our results show the difference in case of the state of herbaceous plants between areas with higher and lower game density. -
Preparatory studies for modelling production on protected grasslands
64-69Views:151There is a mutual dependence between nature conservation activity and agriculture in Hungary, as the management of the protected areas cannot be achieved without ecological farming methods. Moreover, viable economic activity can be only imagined through the harmonization of agricultural and nature conservation interests. From a nature conservation point of view, grass management systems play the greatest role in domestic agricultural systems. Yet, due to the prohibition of certain management methods and the spatial and temporal restraints on grazing, nature conservation activities have priority on protected grasslands. While nature conservation activity is still of prominent importance, it is not equally suitable for the economical management of protected grasslands per se. With our examinations, we would like to emphasize the common interests of these mutually dependent activities and to promote bilateral cooperation. Our aim is to model the production of grass on the great pastureland of Hajdúbagos. Potential grass production levels are easily calculable with a computer model based on data collected through a series of test harvests, as well as by factoring in changing climatic factors and by simulating the effects of grazing animal species and stocks. This model is not only useful for determining the optimal number of the grazing animal stock and grazing method, and therefore the most suitable management strategy, but it also supports local farmers to be able to plan their activities. In this way, both nature conservation and economic aims can be easily harmonized, which would be an important factor for the sustainable development of rural areas.
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Production technology development of millet at different ecological conditions
63-67Views:135The millet is a very special plant with good adaptation that gives the possibility for the late sowing and secondary production. However the effects of late sowing modifies the efficiency of the agrotechnological elements. The exainations – focused on this aspect – was conducted in the DU RINY and DU RIK in small plots in four replications in 2014. Among the examined factors (sowing time, nutrient supply, growing area) sowing time had the largest effect. The effectiveness of the agrotechnological elements decreases under unfavourable circumstances caused by the late sowing.
The agrotechnical elements modifies the yields in the examined genotype. Sowing time had the biggest effect on the yields of millet. The genotype „Maxi” had the highest yield in the different treatment variations.
The yield differences were significant between the sowing time and plant density variations, but the nutrient supply had not significant effect (the rate of precipitation was unfavourable in 2014 season).
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The system of fertigation-advising by the open-field vegetable growing with environment-protecting view
319-321Views:85The changed economical surroundings and the more strict ecological rules induced a need of changes also of the system of advisory on nutrient-supply of vegetable growing. There were many experiences and scientific results born after the last summarizing vegetable fertilization directives (1981), which allowed finishing a new system of advisory mentioned and presented above. We are sure, that the new directives, based on the modern view of vegetable production and also laying on economical possibilities will help the domestic vegetable production to stay competitive on the domestic and the foreign markets both.
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Improvement of black locust (Robinia pseudoacacia L.) growing under marginal site conditions in Hungary: case studies
129-133Views:341In Hungary, black locust (Robinia pseudoacacia L.) is considered as an important exotic stand-forming tree species growing mostly under unfavourable ecological conditions for forest management. Due to climate change effects, its importance is increasing in many other countries, too. As a result of a selection programme, new black locust clones were tested in clone trials. Juvenile growth of 12 micropropagated black locust clones in two plots series established at different dates were evaluated in central Hungary under marginal site conditions. At age of 7 the clone R. p. ‘Bácska’ (‘KH 56A2/5’), at age of 10 the clones R.p. ‘Homoki’ (‘MB17D3/4’) and ‘PV201E2/4’ appeared to be especially promising for mass production. Based on the data obtained from the performed trials, it can also be concluded that tissue culture can be considered as a suitable tool for propagating superior individuals and offers new prospects for the rapid cloning of selected genotypes used for plantation forestry.
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The impact of sowingdate and production area on the yield of white lupin (Lupinus albus L.) on Nyírség brown forest soil
133-137Views:130The lupine is very sensitive to the different ecological conditions. The examinations of lupine was started in 2003 and our aim is determine yield components which directly affecting crop yields (flower, pod and seed number per plants) in different sowing times (3 times, two weeks apart) and growing area area (240, 480, 720 cm2) combinations. According to our results the sowing times, the growing area and the meteorological conditions are influence on yield significantly. Our data suggest that the early sowing and large growing area combination is favourable to rate of fertilized plants and to development of yield. Later sowing reduces the seed yield depending on the cropyear. In our experiment, the decrease of yield was in the unfavourable year (2003) 20–96%, and in the most favourable meteorological conditions (2004) 10–79%, and in rich rainfall year (2005) 15–88%.
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Preface
5Views:32In the frame of a common “Hungarian-Ukrainian Intergovernmental S&T Cooperation Programme” which title is “Change of soils ecological characteristics of Ukraine and Hungary in the conditions of anthropogenic transformed ecosystems and optimization of biological processes of plants primary feeds elements mobilization” a Workshop was held in Debrecen. The member institutes of project participated with different presentation in this program.
The title of Workshop was: “Anthropogenic effect on the properties of Middle and Eastern European chernozem soils and on the sustainable agricultural production”.
The aim of the Workshop was to give relevant information about the present situation of the Middle and Eastern European Chernozem soils, especially emphasize the effect of different loading on the quality (properties) of chernozem soils. With the Workshop we would like to create a tradition for discussion about the anthropogenic effect on the soil properties and through it on the productivity of different soils. It was a forum for discussion of research results related to problems and possibilities for prevention of soil quality. With this possibility we would like to contribute to the sustainable agricultural production.
The papers were read for the publisher and we would like to show them in a separate supplement of Journal of Agricultural Sciences, Acta Agraria Debreceniensis as one of the results of the project.
The papers comply with the requirements of the scientific issue except those two which show the university and the department of the Ukrainian partner taking part in this project.
The participant Institutes of the project:
- Dnepropetrovsk National University, Faculty of Biology and Ecology;
- Kryvyi Rig Botanical Garden NAS of Ukraine, Plant Physiology & Soil Biology Department;
- Department of Agrochemistry and Soil Sciences of Centre for Agricultural and Applied Economics;
- Research Institute of Karcag, Centre for Agricultural and Applied Economics. The collaboration with Ukrainian partners was successful and we have confidence in the further cooperation in scientific research. -
Effect of cropping technologies on the yield of dry bean variety ’Diana’
37-41Views:125An experiment on three dry bean varieties (Start, Hópehely, Diana), using different sowing-times, fertilizers and plant densities was performed on sandy soil in the University of Debrecen, Centre for Agricultural Sciences, Research Institute of Nyíregyháza in 2015. The aim of the experiment was to study which treatment gives the highest yield, and whether the different treatments result in significant differences in the yields. In this paper the dry bean yield at ‘Diana’ variety is analyzed.
The treatments were done with three fertilizer doses and three plant densities at different sowing-times (April 24; May 8; May 18). As a result of the high temperature and the drought during the growth season, the yields we harvested were in low, which shows the ecological sensitivity of the plant we examined.
We concluded that the poorest yield was harvested at the third sowing-time. There was no significant difference in the yields at the first and second sowing- time. Examining all the three fertilizer treatments we applied at the experiment, we achieved the highest yields in the control plots. It might be due to the weak efficiency of nitrogen fertilizer under the extremely dry conditions. The highest yield was harvested at the control treatments during the second sowing-time. Regarding the effect of the plant densities, the highest crop yield was achieved at the treatment using 400 000 germs ha-1, followed by 300 000 germs ha-1 and 200 000 germs ha-1.
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Correlations of the global, regional and local factors of the anthropogenic effects on the water reserves of the Earth’s crust
85-92Views:102The decrease in Earth's drinking water resources and the degradation of its quality has become a critical problem. Our planet's total water supply is estimated to be around 2 billion km3s. This is only 1% of Earth's own weight. Of this small amount only a tiny 3% is fresh water, of which 79% is forzen in glaciers and 1% is present as surface waters.The ratio of water stored in soil is around 20%. This is 0.2% of the total water supply. Our study aims to summarize the layered groundwater aquifer systems and its changes which are the results of anthropogenic effects in both global and hungarian respects and also for the region of Debrecen.In particular with regard to the geological and ecological level where irreversible
processes take place. All this is discussed in the context of cause and effect. Pointing out the dangers of excessive deep groundwater extraction and the contamination caused by toxic substances that are the byproducts of modern life. In addition we discuss the Water Directive of the European Union which gives a policy for community action concerning the goal to achive the status of „in good condition” for our waters till 2015. -
Testing disease resistance in autumn wheat genotypes by means of field experiments
30-40Views:94According to our scientific results we can state that we have to use integrated pesticides management in crop protection against the diseases of winter wheat. One of the most important elements of IPM is to select a genotype characterised by good resistance to diseases (and by high yield ability and excellent baking quality). It is especially important that the wheat variety have tolerance against not only to one or two leaf and spike (grain) diseases, but „complex” tolerance. It is not necessary to give up the growing of a variety which has susceptibility to different diseases because we can protect it using appropriate chemical management. In the intensive growing stage of wheat (BBCH 32-37) we can use a noncompulsary fungicide-treatment (depending on e. g. the infection, ecological conditions) and, at the beginning of the flowering stage
(BBCH 59-65), we have to use a compulsary fungicide-treatment (in spite of e. g. special weather conditions, resistance genotype)to ensure high yield and good quality. -
Comparative analysis on the fertiliser responses of Martonvásár maize hybrids in long-term experiments
111-117Views:78The results of experiments carried out in the Agricultural Research Institute of the Hungarian Academy of Sciences clearly show that in the case of hybrids grown in a monoculture greater fertiliser responses can be achieved with increasing rates of N fertiliser than in crop rotations. In the monoculture experiment the parameters investigated reached their maximum values at a rate of 240 kg/ha N fertiliser, with the exception of 1000-kernel mass and starch content. In both cases the starch content was highest in the untreated control, gradually declining as the N rates increased. Among the parameters recorded in the crop rotation, the values of the dry grain yield, the 1000-kernel mass, the protein yield and the starch yield were greatest at the 160 kg/ha N fertiliser rate, exhibiting a decrease at 240 kg/ha. Maximum values for the protein content and SPAD index were recorded at the highest N rate. It is important to note, however, that although the N treatments caused significant differences compared to the untreated control, the differences between the N treatments were not significant.
In the given experimental year the values achieved for the untreated control in the crop rotation could only be achieved in the monoculture experiment at a fertiliser rate of 160 kg/ha N, indicating that N fertiliser rates could be reduced using a satisfactory crop sequence, which could be beneficial from the point of view of environmental pollution, crop protection and cost reduction.
The weather in 2006 was favourable for maize production, allowing comparative analysis to be made of the genetically determined traits of the hybrids. Among the three hybrids grown in the monoculture experiment, Maraton produced the best yield, giving maximum values of the parameters tested at a fertiliser rate of 240 kg/ha N. The poorest results were recorded for Mv 277, which could be attributed to the fact that the hybrid belongs to the FAO 200 maturity group, while the other hybrids had higher FAO numbers. Maraton also gave the highest yields in the crop rotation experiment at the 160 kg/ha N level. All three hybrids were found to make excellent use of the natural nutrient content of the soil.
It was proved that the protein content of maize hybrids can only be slightly improved by N fertilisation, as this trait is genetically coded, while the starch content depends to the greatest extent on the ecological factors experienced during the growing season.