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Long-term experiments on chernozem soil in the University of Debrecen
357-369Views:201The impact of agrotechnical management practices (nutrient and water supply, crop rotation, crop protection, genotype) on the yields of winter wheat and maize and on the soil water and nutrient cycles was studied in long-term experiments set up in 1983 in Eastern Hungary on chernozem soil. The long-term experiments have shown that nitrogen fertilizer rates exceeding the N-optimum of winter wheat resulted in the accumulation of NO3-N in the soil. Winter wheat varieties can be classified into four groups based on their natural nutrient utilization and their fertilizer response. The fertilizer responses of wheat varieties depended on crop year (6.5–8.9 t ha-1 maximum yields in 2011–2015 years) and the genotypes (in 2012 the difference was ~3 t ha-1 among varieties). The optimum N(+PK) doses varied between 30–150 kg ha-1 in different crop years. In maize production fertilization, irrigation and crop rotation have decision role on the yields. The efficiency of fertilization modified by cropyear (in dry 891–1315 kg ha-1, in average 1927–4042 kg ha-1, in rainy cropyear 2051–4473 kg ha-1 yield surpluses of maize, respectively) and crop rotation (in monoculture 1315–4473 kg ha-1, in biculture 924–2727 kg ha-1 and triculture 891–2291 kg ha-1 yield surpluses of maize, respectively). The optimum fertilization could improve the water use efficiency in maize production.
Our long-term experiments gave important ecological and agronomic information to guide regional development of sustainable cropping systems.
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The Influence of Cropyear on the Yield and Yield Safety of Different Sunflower Hybrids
68-73Views:98The effectiveness of plant production is basically influenced by the ecological, biological and agricultural technical factors. There are many kinds of sunflower hybrids which differres in their adaptability. If we want to increase the efficiency of sunflower production, we have to design different technologies for each hybrid. In the last decade, the range of sunflower hybrids increased exceedingly. This is the reason why we have to do experiments with them and examine what the relationship among genotypes, the environment and the hybrids is.
We made our experiments at the Látóképi Experimental Station of the University of Debrecen. We had 57 hybrids in 2001, and 44 in 2002 and 2003. We used only just those hybrids which were planted in every year.
In 2001 the months at summer were hot and the distribution of rainfall was extreme. In the beginning of the year 2002, the summer was also hot. During the abscessing period, the temperature was under the 30 years average and the rainless period was typical. In 2003, the temperature was extrame and the rainfall during the growing season was dry. The yield average which was determined after the three years in the very early group averaged 3998,9 kg/ha. The best hybrids were the LG 5385 (4273,3 kg/ha) and the Magóg (4134,4 kg/ha). The early group’s average was 4129,4 kg/ha. The best hybrid was the Astor in the early group. The middle group’s average was 4169 kg/ha and the Zoltán had a better yield than average (4238 kg/ha). In the confectionary group the Iregi szürke csíkos (3579,9 kg/ha) reached the best yield and it is above the average to it’s group (3225 kg/ha).
To estimate the results, we used factor analysis. Its results allow us to say that rainfall first and second part of June has a negative influence on yield. Aswith to the yield, yield safety is also important to know, which shows the adaptability of the hybrid.
After examining the CV% in the three years we can say that the most stable hybrids were in the very early group Samanta (10,94 CV%) and the LG 5385 (12 CV%) In the early group, the most reliable hybrids were Altesse RM (6,9 CV%) and the Astor (10,8 CV%) and the end in the middle group the Lympil (10 CV%) and in the confectionary group the Birdy (9,8 CV%) and IS 8004 (12 CV%) were the best.
After examining yield and yield safety, our conclusions are that in the Hajdúsági löszhát, the very early group LG 5385, early group Altesse RM, middle group Lympil and the parandial group IS 8004 hybrid had the highest yield and the best yield stability. -
Examination of two artichoke cultivars under single year Hungarian climate conditions
112-115Views:71Based on the results of a previous experiment, we concluded that by choosing a suitable cultivar, it is possible to produce artichoke in a one-year cultivation system in Hungarian weather circumstances. The objective of the present experiment was to investigate the performance of two Californian artichoke cultivars (Green Globe, Imperial Star) under the local conditions. Experiments were conducted in 2002 and 2003, by using four
different sowing and two different planting dates (03.01. and 03.20. – planting 05.07.; 04.24. and 05.06. – planting 06.12.). For both cultivars, 100% of the plants initiated buds. In most of the cases, Imperial Star produced higher total and marketable yields than Green Globe did, while it formed bigger and more uniform buds. Our opinion is that the main reason for this result was that Imperial Star tolerated the dry and warm Hungarian summer much better. Irrespective of the variety by earlier sowing dates higher total yield was achieved. Based on our results, we found that under Hungarian circumstances, both cultivars could produce acceptable total yields. However, the weather circumstances of the given year influenced bud quality, and thus marketable yield, to a great extent. -
The Effect of Fertilization and Irrigation on Maize(Zea mays L.) Production
26-29Views:110In a long-term field experiment set up at the Látókép experimental station of the Center of Agricultural Sciences of Debrecen University, the data of the last five years (1995-1999) were analyzed to determine the crop production factors with the greatest influence on maize production and the relationship and interactions between irrigation and fertilization.
In the extremely dry year of 1995, fertilization was found to cause substantial yield depression in the absence of irrigation. According to results of analysis of variance, fertilization significantly reduced the maize yield by 40-90% compared to control plots. Under irrigated conditions, there was a considerable increase in the maize yield, the yield surplus being 4.4-9.4 t ha-1, depending on the nutrient supply level.
During the period from 1996-1999, when rainfall conditions were favorable for maize, fertilization significantly increased the maize yield even without irrigation over the average of the four years. The yield surplus due to fertilization was 3.9-4.6 t ha-1, depending on the fertilization rates. The maximum yield surplus was obtained on plots fertilized with 120 N kg ha-1, while at the rate of 240 N kg ha-1 the maize yield did not differ significantly from this value. During the period examined, corn yield was significantly higher at all three nutrient supply levels as the result of irrigation than in the non-irrigated treatment. As in the case of non-irrigated conditions, the highest fertilizer dose did not result in a substantial yield increase. An analysis of the interaction between fertilization and irrigation indicated that the yield-increasing effect of fertilization was not significantly different under irrigated and non-irrigated conditions. The significant year x irrigation interaction was confirmed by the fact that the yield surplus (1.3-2.3 t ha-1) differed greatly from the irrigation effect recorded in 1995. -
Effect of Soil Covering on the Soil Enzyme Activity of Integrated Orchard
20-29Views:82The purpose of our experiments is to discover the effect of different soil cover matters (agrofoil and black polyethylene) on the activity of some enzymes (phosphatase, saccharase, urease, catalase, dehydrogenase) occuring in soil. Soil samples were taken from a cider apple plantation of the Fruit Producing Research and Advisory Kht Újfehértó. The enzyme activity was measured according to Krámer and Erdei (1959a), Kuprevič and Tsherbakova (1956), Kuprevič et al. (1966), Frankenberger and Johanson (1983), Mersi and Schinner (1991). Soil moisture content was by conventional (drying chamber) method measured during every sampling and enzyme activity was transpolated to absolute dry soil. Results were estimated by mathematical methods (variation analysis, correlation counting). Soil samples were taken by trials 5 times (in every two months) a year in the vegetation period from March to November.
By recording the monthly changes of the enzyme activity we have observed the following. The activity of the phosphatase was generally the highest in May and the lowest in November. Depending on the trials, high values were also measured in March and September. The activity of the saccharase was generally the highest in November and the lowest in June, but at the same time peaks even occured in May and September. The highest urease avtivity was measured in September and November, and the lowest activity in May and July, also depending on the trials. In the year 2000, after a deep point in March, the activity of the catalase was the highest in November or by certain trials in September. In 2001, the lowest activity was also measured in March, but the highest activity appeared in November in case of one-minute trial, and in May in consequence of two-minute trial. Finally the activity of dehydrogenase was the highest in November and the lowest in July apart from the model years.
There were essential differences in rainfall of the two experimental years which was reflected in the enzyme activities. There was a poor positive significant relationship between soil moisture content and enzyme activity values in case of phosphatase, saccharase, urease (r=0,426; 0,480; 0,396) respectively. In case of catalase1 (r=0,518), catalase (r=0,556), dehydrogenase (r=0,559) we obtained a medium strong positive relationship between soil moisture content and enzyme activity values. By evaluating the effect of different trials in case of every examined enzyme significantly higher values were detected in soils covered by agrofoil (a porous black polyethylene) than in soils covered by black polyethylene or in uncovered soils. Moreover, the soil covered by black polyethylene showed significantly higher enzyme activities (besides phosphatase) than the control soil. Thus soil-covering meant statistically significant advantages in enzyme activity as opposed to uncovered soil proved. -
Effect of Storage on Fruitquality of Apricot (Prunus Armeniaca)
164-169Views:96The quality of a product is determined by numerous characteristics. As quality characteristics are polygenic, they cannot be improved easily. Moreover, there often is a negative correlation between the different parameters in the case of apricot. The firmness of fruits decreases with increasing size. The year effect also has a great influence on the expression of the potential quality of the given cultivar.
Our examinations were carried out in 2004 at Boldogkőváralja, in the cold storage plant of the Northcot Ltd. We monitored the development of fruits from fructification until harvest, and also the quality changes during storage. 100 fruits were observed from each cultivar directly after harvest. We measured height, width, weight, firmness, dry matter content and seed weight. From each cultivar, 100 fruits were stored, of which 25 fruits were observed each week. The value and the dynamics of the changes in the parameters compared to the values at harvest varied greatly for the different cultivars. Strong correlations between the parameters have not been found within one cultivar either. The heavier fruits did not lose more weight, either in absolute value or relatively, than the lighter fruits. The increase in the firmness of fruits was not accompanied with a desirable decrease in the dry matter content. -
Determining elements of variety-specific maize production technology
157-161Views:62Our aim was to work out such new maize fertilizer methods and models which can reduce the harmful effects of fertilization, can
maintain the soil fertility and can moderate the yield fluctuation (nowadays 50-60 %).
The soil of our experimental projects was meadow soil. The soil could be characterized by high clay content and pour phosphorus and
medium potassium contents. In the last decade, out of ten years six years were dry and hot in our region. So the importance of crop-rotation
is increasing and we have to strive for using the appropriate crop rotation.
The yields of maize in monoculture crop rotation decreased by 1-3 t ha-1 in each dry year during the experiment (1983, 1990, 1992,
1993, 1994, 1995, 1998, 2000, 2003, and 2007). The most favourable forecrop of maize was wheat, medium was the biculture crop rotation
and the worst crop rotation was the monoculture.
There is a strong correlation between the sowing time and the yield of maize hybrids, but this interactive effect can be modified by the
amount and distribution of precipitation in the vegetation period. At the early sowing time, the grain moistures were 5-12 % lower compared
to the late sowing time and 4-5 % lower compared to the optimum sowing treatment.
There are great differences among the plant density of different maize hybrids. There are hybrids sensitive to higher plant density and
there are hybrids with wide and narrow optimum plant densities.
The agro-ecological optimum fertilizer dosage of hybrids with a longer season (FAO 400-500) was N 30-40 kg ha-1 higher in favourable
years as compared to early hybrids.
We can summarize our results by saying that we have to use hybrid-specific technologies in maize production. In the future, we have to
increase the level of inputs and have to apply the best appropriate hybrids and with respect to the agroecologial conditions, we can better
utilize the genetic yield potential. -
The scientific background of competitive maize production
33-46Views:272The effect and interaction of crop production factors on maize yield has been examined for nearly 40 years at the Látókép Experiment Site of the University of Debrecen in a long-term field experiment that is unique and acknowledged in Europe. The research aim is to evaluate the effect of fertilisation, tillage, genotype, sowing, plant density, crop protection and irrigation. The analysis of the database of the examined period makes it possible to evaluate maize yield, as well as the effect of crop production factors and crop year, as well as the interaction between these factors.
Based on the different tillage methods, it can be concluded that autumn ploughing provides the highest yield, but its effect significantly differed in irrigated and non-irrigated treatments. The periodical application of strip tillage is justified in areas with favourable soil conditions and free from compated layers (e.g. strip – strip – ploughing – loosening). Under conditions prone to drought, but especially in several consecutive years, a plant density of 70–80 thousand crops per hectare should be used in the case of favourable precipitation supply, but 60 thousand crops per hectare should not be exceeded in dry crop years. The yield increasing effect of fertilisation is significant both under non-irrigated and irrigated conditions, but it is much more moderate in the non-irrigated treatment.
Selecting the optimum sowing date is of key importance from the aspect of maize yield, especially in dry crop years. Irrigation is not enough in itself without intensive nutrient management, since it may lead to yield decrease.
The results of research, development and innovation, which are based on the performed long-term field experiment, contribute to the production technological methods which provide an opportunity to use sowing seeds, fertilisers and pesticides in a regionally tailored and differentiated way, adapted to the specific needs of the given plot, as well as to plan each operation and to implement precision maize production.
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The purple coneflower’s (Echinacea purpurea L.) nutrient requirements investigation in a small plot trial
95-99Views:135During our research, we investigated the purple coneflower's (Echinacea purpurea L.) drug yield and drying loss change with different fertilization settings in a small-plot trial. We measured the raw and dry drug yield, which we harvested in 2016 and in 2017, as well as the drying loss of these yields. Harvest and all other works were performed manually. We dried the harvested herba under prenumbra for three weeks. Based on the obtained data, every fertilization settings’ yield was less than that of the control plots in 2016. We measured the highest drying loss in relation to the N60P80K120 supply in this year. In 2017, we measured the highest yield data in the N75P100K150 fertilization setting.We made single-factor variance analysis to investigate the connection between the quantity of the raw, the dried herba, the drying loss and the different nutrient settings -
Application of mycorrhizae and rhizobacteria inoculations in the cultivation of processing tomato under water shortage
111-118Views:44The effect of mycorrhizal fungi and plant growth promoting rhizobacteria on some physiological properties, yield and soluble solid content (Brix) of ‘Uno Rosso’ F1 processing tomato was studied under water scarcity. Inoculation was performed with mycorrhizal fungi (M) and rhizobacteria preparation (PH) at sowing (M1, PH1) and sowing + planting (M2, PH2). The treated and untreated plants were grown with regular irrigation (RI = ET100%), with deficit irrigation (DI = ET50%) and without irrigation (I0). In drought, the canopy temperature of plants inoculated with arbuscular mycorrhizal fungi (M1, M2) decreased significantly, however, the decrease was small in those treated with the bacterium (PH1, PH2), while the SPAD value of the leaves of plants treated only with Phylazonit increased significantly. On two occasions, inoculations (M2, PH2) significantly increased the total yield and marketable yield, however, under water deficiency, a higher rate of green yield was detected than untreated plants. In dry year using deficit irrigation, the one-time inoculation (M1, PH1) provided a more favorable Brix value, while the double treatments reduced the Brix. In moderate water scarcity, the use of mycorrhizal inoculation (M2) is preferable, while under weak water stress, the use of rhizobacteria inoculation (PH2) is more favorable.
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Magnesium uptake dynamism of maize (Zea mays L.) on prairie soil
83-89Views:70Different influence factors on the magnesium (Mg) uptake in case of three maize hybrids with different long vegetation period have been investigated at the Experimental Station of the University of Debrecen, Centre of Agricultural Sciences and Engineering, at Debrecen-Látókép. The soil of the experiment is a calcareous chernozem, based on loess, with high fertility, that is characteristic for soils of the region Hajdúság.
Upon irrigation is the experiment divided to main plots, by different hybrids into sub-plots, while treatments of five nutrientsupply levels with fixed N:P2O5:K2O rate (beside control)mean sub-subplots. Soil samples were taken from the upper, cultivated soil layer 3 times during the year 2008. Their pH has been measures in a 0.01 M CaCl2-solution and their Mg-content from the same solution and from ammonium-lactate acetic acid (AL) extract. Plant samples were taken seven times in the vegetation period, of which we measured the Mg-content. Beside this, the during the
vegetation period by maize biomass extracted Mg-amount has been calculated using fresh and dry matter weights. The effects of irrigation, hybrids and nutrient-supply levels on the soil pH and on the AL- and CaCl2-extractable Mg-amount have been studied, as well. After that I tried to find a correlation between soil pH and the Mg-content of soil determined in different extractants, beside this between the by the two solutions extracted Mg-amount. -
The impacts of spring basal and side dressing on maize yield
83-86Views:172The yield potential of maize is very high. According to Tollenaar (1983), maize yield potential is as high as 25 t ha-1 (absolute dry yield) which is the highest among all cereals. In order to fully utilise this high yield potential, proper nutrient replenishment is of chief importance among all agrotechnical factors.
The aim of research was to examine the effect of nitrogen fertiliser applied as basal and side dressing on maize yield.
The measurements were performed at the Látókép experiment site (47° 33’ N, 21° 26’ E, 111 m asl) of the Centre for Agricultural Sciences of the University of Debrecen on mid-heavy calcareous chernozem soil with deep humus layer in an established experiment in 2011, 2012 and 2013. The trial design was split-split-plot with two replications.
Based on the experiment results, it can be established that the nutrient uptake of maize is greatly dependent on the amount of water store in the soil. From the aspect of the development of the maize plant and water supply, the most determinant factor was the distribution of precipitation over the growing season and not the amount precipitation. This is shown by the fact there was only 276 mm precipitation – which was favourably distributed – in 2012 to increase the availability of nutrients and the main average was the highest in this year (14.394 t ha-1).
Spring basal dressing helped maize development in all three years even on chernozem soil which is well supplied with nutrients. Although the effect of side dressing did not result in any yield increase, it could still contribute to mitigating the stress effects caused by environmental factors. Altogether, nutrient supply adapted to the various development stages of maize can favourably affect the success of maize production.
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The role of green manure crops in Hungarian plant production
49-53Views:201According to the data of KSH (Hungarian Central Statistical Office), the sowing area of cereals in the crop year 2016 was over 2.56 million ha, on which winter wheat and maize were produced in a rate of around 50–50%. Regarding these data it is obvious that the domestic cropping structure has been simplified and become unilateral. This unfavourable crop rotation system causes several problems. The number of Hungarian livestock decreased in the past decades. The amount of manure was 24 million tons in 1960, but only hardly 4.5 million tons of organic manure was applied in 2016. Therefore, the importance of other possibilities, alternatives for organic matter recovery have become enhanced. This is especially important from the aspect of sustainable plant production. The fact that the European Union has introduced new directives for subsidiaries in 2015 has to be noted as well.
The objective of the set experiment is to find new technological solutions that are suitable for the execution of sustainable plant production by inadequate crop rotation, organic substance recovery conditions or under more unfavourable climatic conditions.
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Testing a biological active plant extract’s antifungal effect against soil fungi
247-252Views:95In Hungary today is about 5 million hectares of agricultural land contaminated with ragweed. The ragweed problem a year is about 60 billion HUF to be paid, of which 30 billion are used to reduce the agricultural damage. Experiments with ragweed pollen has mainly been carried out in connection with terms of allergy. The other biochemical experiments and studies with this plant, have so far been the scientific horizons of public life, boosted the edge. We wanted to demonstrate that the ragweed, which is a weed, containsbiological active (for example: antifungal) compounds. For our experiments in the previous cycle of flowering, plants were collected manually, with its roots and with each plant part. The extraction of the substance from dry plant – meal was carried out using appropriate solvents. The biological activity of ragweed-extracts were tested against fungi isolated from soils and meadow with different mode of cultivation. Our results suggest that ragweed contains biologically active substances, which inhibit the growth of fungi, depending on the concentration of active ingredients of the plant.
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The effect of plant density to the yield results and the yield components of maize hybrids
89-93Views:133Maize is the crop that is produced on the second largest area in our country, in Hungary. It is planted on nearly 25% of the country’s growing area and it was produced on 1 090 439 hectares in 2016. Despite the continuous development of the biological basis and production
technology, the growth of the yield results is not constant, its fluctuation is significant. It can be even up to 60%, because of the extremity of the years. The exploitation of the yield potential of modern hybrids is possible if we harmonize the effects of the ecological factors and properly applied instruments of agro technology and by these we ensure their interaction to reach a favorable outcome. The applied plant density is an important, well researched, but at industrial level a not enough utilized element of the maize production.
The results of the extensive tests, done between 2009 and 2015, showed that the genotype, the year effect and the plant density are in strong correlation with each other determining the yield results. In the past seven years the examined genotypes reached the highest yield
performance at the highest plant densities. The early hybrids (RM90–95, FAO 200–300) are capable of producing them at higher plant density, while in case of the mid and late maturity varieties the further increasing of the density after reaching the optimum level led to yield depression.
According to our experimental results, the yield is in close positive correlation with the increase of the plant density. The effect of the growing season has great significance in forming the yield results and this determines the applicable plant density too.
The yield of maize is determined by a resultant of components. The main component is the number of ears per plant and the amount of kernels per ear, which is calculated from the number of kernels on an ear and the weight of them. The number of the kernels on an ear is
calculated from the number of rows on the cob multiplied by the number of seeds in one row on the cob. In dry years, at lower yield levels the yield decreases because of the shorter ears, while at the higher levels the number of kernels in a row and the thousand-kernel weight decreases,causing yield depression this way. From our examinations it turned out that the plant density reaction of a genotype is individual, every variety reaches its maximum kernel number per hectare – in other words the maximum yield - in an individual way. -
The effect of different genotype cattle grazing on the nutrient content of saline grasslands vegetation
46-50Views:173Maintaining saline grasslands in good condition, preserving their yield and diversity is important not only for the purpose of nature conservation, but also for farming. Therefore, the primary purpose of our study is to analyse the effect of pasture use of the smaller weight extensive and the larger weight intensive beef cattle on the grassland vegetation and nutrient content. In this way, we can answer the question whether grazing for nature conservation can be achieved with more profitable, more economical and more intense varieties.
The tests were carried out in May 2016 and May 2017, in the Hortobágy National Park (Pap-ere and Zám puszta), where a total of 16 sample areas were analysed. These areas are grazed with extensive beef cattle (Hungarian grey) and mixed genotype of intensive cattle. The associations were selected along a moisture gradient, such as wet salt marsh (Bolboschoenetum maritimi) and drier saline meadow (Beckmannion eruciformis). All the vegetative material collected both years in May was analysed for the following parameters: dry matter, crude protein, crude fibre and life-sustaining net energy content. We compared the effects of medium grazing (0.46 livestock/ha) and abandonment on vegetation and nutrient content.
We examined the effect of (i) grazing, (ii) different grasslands (salt marsh, saline meadow) and (iii) grazing of different cattle breeds (Hungarian grey, intensive beef) on the nutrient content of the vegetation of grasslands Based on our results, it was found that grazing had an impact on crude protein and life-sustaining net energy content. The highest crude protein content (12.75 m/m%) was obtained in the year 2017 in the area where higher density had been grazed for two years. For the lifesustaining net energy, the highest value (5.05 MJ/kg d.m.) was also obtained in 2017 and the lowest in 2016. Furthermore, it was found that there was no significant difference between the effect of the two cattle breeds on the parameters examined. Significant effects were observed only in the case of life-sustaining net energy: in the area of intensive beef cattle we received a higher value (5.15 MJ/kg body weight) than in the area with extensive beef cattle (4.96 MJ/kg body weight).
Our results have also shown that cattle grazing is of the utmost importance for the maintenance of both wet and mesophilous habitats. Based on our three-year study, we can say that grazing by both extensive and intensive cattle breeds is suitable for the management of saline habitats.
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The effect of crop year and agrotechnical factors on the yield of various maturity groups of Limagrain maize hybirds
19-23Views:130The Limagrain maize hybrids in different maturity groups were examined at the Látókép Experimental Station of the Centre of Agricultural Sciences and Engineering, University of Debrecen on a calcareous chernozem soil with loam texture, between 2001 and 2007 in a multifactorial long-term field trial. Doses of fertilizers: 1 N:0.75 P2O5:0.88 K2O fixed proportion of NPK doses. The basic dose of nitrogen is 30 kg ha-1. The application of fertilization was 1, 2, 3, 4, and 5 times more than the basic dose, beside of untreated control. The long-term field trial is performed in none irrigated and in irrigated version.
The goal of the study was to analyze the effect of precipitation (environment factor) in one hand, and to evaluate the effect of fertilization and irrigation (agrotechnical factors) on the yield of maize hybrids in different maturity groups in the other hand. At the same time I studied the effect of interaction of different factors on the yield of maize.Analysis the yield of Limagrain hybrids revealed: the years considerably affected the level of the yield. In dry years the yield was 1.351 t ha-1 less, than in rainy years. As the effect of fertilization the yield increased, the statistically proved biggest increment was at level of 90 kg N ha-1. Evaluating the maturity groups, FAO 300 hybrids reached higher level of yield.
In non irrigated conditions in the average of the seven years 60 kg N ha-1 was sufficient to reach the maximum yield. The efficiency of fertilization on yield in irrigated version increased, 120 kg N ha-1 assured the reliable level of yield.
Without irrigation in comparison to the results of FAO 200 group, with the growth of FAO numbers the yield is increasing in all cases. The most significant increase was at FAO 300 (3.562 t ha-1). With irrigation the greatest difference in yield was in FAO 400 (+2.720 t ha-1) compared to FAO 200. -
Preliminary results of the combined production of duckweed Spirodela polyrhiza and common carp (Cyprinus carpio) in an aquaponic system
83-89Views:65As a result of population growth, increasin amount of food is needed, and agriculture is under an increasing burden to meet these needs. Traditional agriculture is often attacked due to its environmental impact. We must find alternative, environmentally friendly ways to produce more food. Aquaponics is a closed system in which we can produce both fish and plants at the same time. Duckweed species are small, aquatic, floating plants belonging to angiosperms. It can potentially be an alternative protein source, due to its high protein content, good amino acid supply, and rapid growth. Under suitable conditions, it doubles its weight in 2–4 days, and can reach a yield of 30 t ha-1 year-1in dry matter. It forms a carpet on top of the water and can be found in slow-moving or still waters. Since they are resistant to a wide range of nutrient concentrations, they are also suitable for cleaning wastewater (such as eutrophicated lakes, sewage reservoirs, liquid manure storage). Fish feed is the primary nutrient source for aquaponic systems, which usually contains fishmeal. If duckweed can be used as an alternative for fishmeal in the feed, it could improve the sustainability of the aquaponic and aquaculture systems. In this study, the aim was to develop an optimal harvesting protocol for duckweed Spirodela polyrhiza under aquaponic conditions. In a four weeks experiments, four harvesting protocols were set up, a control where only biomass measurements were made, a 25% group where 25% of the biomass at the time of measurement was harvested, and a 50% and a 75% group where at the time of measurement 50% and 75% of the biomass was harvested. Three replicates were used per treatment. We weighed the biomass every week and removed the amount corresponding to the group. Based on the preliminary results, it can be said that more biomass was obtained in the groups with the 25% harvesting protocol and the control group.