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Studies of plant density increase – on maize hybrids of various genotypes on chernozem soil
Published March 11, 2014
87-92

The yield and crop safety of maize are influenced by numerous ecological, biological and agrotechnical factors. It is of special importance to study one of the agrotechnical elements, the plant density of maize hybrids, which is influenced by the growing area conditions and the selected hybrid.

We have investigated the effects of three ...different plant numbers (50 thousand plants ha-1, 70 thousand plants ha-1 and 90 thousand plants ha-1) on the yield of 12 maize hybrids of different genotypes in Hajdúság, on calcareous chernozem soil, in the Látókép Research Farm of the University of Debrecen, Centre for Agricultural Sciences, in 2013. The experiment was set in four replications, besides commonly applied agrotechnical actions. In the experiment, 1 hybrid of very early (Sarolta), 9 of early (P 9578, DKC 4014, DKC 4025, P 9175, NK Lucius, Reseda, P 37N01, DKC 4490, P 9494) and 2 of medium (Kenéz, SY Afinity) maturation were used.

With the increase of the plant number, the number of individuals per unit area increases. According to our experimental results, we have concluded that with the increase of the plant number, the yield increased in the average of the hybrids. In the average of the hybrids, in the case of 50 thousand plants ha-1, the yield was 13 130 kg ha-1, in the case of 70 thousand plants ha-1, it was 13 824 kg ha-1, while in the case of 90 thousand plants ha-1, the yield became 13 877 kg ha-1.

In addition to plant density increase, it is necessary to determine the optimal plant number that is the most favourable for the certain hybrid under the given conditions. To fulfil this aim, we have determined the optimal plant number corresponding to the maximum yield of the given hybrid, within the given plant number range. The optimal and applied plant numbers differ, since the optimal one could only be applied under ideal conditions. Since the agrotechnical actions cannot always be carried out in appropriate quality and one has to adapt to the weather conditions, thus we have determined a plant number range in the case of each hybrid. The hybrids were classified into categories of producible in narrow and broad plant number range.

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The effect of plant density on maize yield in average and extremely dry years
Published December 21, 2008
7-16

The yield safety of maize has not been satisfactory in Hungary for decades. Yield is influenced by the combination of several factors.
In recent years, the frequency of dry years increased and fertilization decreased. These factors call for a rational determination of the plant density.
I studied the relationship between plant density and... yield in 2003-2004 and 2007 on meadow soil. 
In 2003, the weather was dry. In the vegetation period, the amount of precipitation was 78.5 mm lower and the temperature was 0.97 °C higher than the average of 30 years, the number of hot days was 47-60 (days with a temperature higher than 30 °C). However, we obtained favourable results under experimental conditions in 2003 after wheat as a forecrop using the fertilizer Kemira Power. 
The weather in 2004 was favourable. In the vegetation period, the amount of precipitation was 93.2 mm higher than the average of 30 years.  Although, the distribution of the precipitation could have been more favourable. The yield of the hybrids ranged between 8.87-10.42 t/ha. Among the studied seven hybrids, the early hybrids gave the highest yield at the highest plant density of 90 thousand plants/ha (PR38Y09, PR38A67, PR37D25, PR37M34). However, FAO 400-500 hybrids gave favourable results also at the low plant density of 45 thousand plants/ha (8-9 t/ha). At this plant density, the aeration of the plant stock was better and the hybrids were prone to bringing several cobs. Yield stagnated with increasing plant density (60 thousand plants/ha), then at 75-90 thousand plants per ha, the yield started to increase again.
In 2004 the yield of hybrids was considerably higher than in the previous year. In contrast to yields of 8.87-10.42 t/ha in 2003, yields in 2004 were around 9-12 t/ha.
The yield of the hybrid XO 902 P is above 12 t/ha already at a plant density of 45 thousand plants/ha. It gives maximum yield at the plant density of 90 thousand plants/ha.
The hybrid PR38P92 showed a good response to changing plant density, but its yield was only 9 t/ha at the low plant density value.
In a favourable year, the yield of the hybrids PR38B85, PR37W05, PR37D25, PR37K85 at a plant density of 45 thousand plants/ha 11 t/ha, while at the higher plant density of 90 thousand plants/ha, it ranges around 13-15 t/ha.

Hybrids PR36K20, PR35Y54, PR34H31 have a good individual yield and they are prone to bringing several cobs in favourable years at a low plant density. Their maximum yield at the plant density of 90 thousand plants/ha is almost 16 t/ha.
In 2007, the weather was similar to that of the extremely dry year of 2003. The amount of precipitation in the vegetation period was 41.9 mm lower than the average of 30 years and its distribution was not favourable either.
In the optimum NPK fertilizer treatment at an optimum plant density, the yield of hybrids ranged between 9.32-10.73 t/ha. The highest yields of 10.22-10.73 t/ha were measured for hybrids PR38A79 (FAO 300) and PR35F73 at a relatively low plant density of 60 thousand plants/ha.
In the average of the hybrids, the optimum NPK dosage was N 131, P2O5 82, K2O 93 kg/ha active ingredient.

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The effect of plant density to the yield results and the yield components of maize hybrids
Published May 16, 2017
89-93

Maize 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 flu...ctuation 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.

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Correlation between the weather in 2017 and the productivity of maize
Published June 30, 2018
89-93
In our research we examined the effect of the hybrid, the nutrient supply, the number of plants and the abiotic factors (temperature, amount of precipitation) on the yield, crop quality and yield stability of maize. We devoted special attention to the natural nutrient utilization ability and fertilizer reaction of... maize. The experiment took place in Hajdúszoboszló on chernozem soil, on a nearly 8 ha field. The size of one plot was 206 m2; therefore, this experiment was half-industrial. We tested six hybrids with different genetic characteristics and growing seasons. I analysed the correlation between the nutrient supply and the yield of maize hybrids with control treatment (treatment without fertilization) and with N 80, P2O5 60, K2O 70 kg ha-1 and N 160, P2O5 120, K2O 140 kg ha-1 fertilizer treatments. The yield increasing effect of the fertilizer also depended on the number of plants per hectare to a great extent. The number of plants of the six tested hybrids was 60, 70, and 80 thousand plants ha-1.
In Hajdúszoboszló in 2017, up to October, 445.8 mm of rain fell, which is in line with the average values of 30 years, and is only 45.7 mm less than those. In 2017, the effect of increasing the plant number was slighter. Averaged over the observed fertilizer treatments and hybrids, the yield was 9.10 t ha-1 with 60 thousand plants ha-1, 9.11 t ha-1 with 70 thousand plants ha-1 and 9.12 t ha-1 with 80 thousand plants ha-1. Without fertilization, in most cases, increasing the plant number from 60 thousand plants ha-1 to 70-80 thousand plants ha-1 does not increased the yield but decreased it. With N80+PK treatment the yield changed between 8.90 and 11.27 t ha-1. The effect of increasing the plant number was just slightly observable and did not show a clear tendency. The effect of changing the plant number, even with the highest dosage of fertilizers, could not be detected adequately. In contrast with the plant number, the effect of the different fertilizer treatments was expressly traceable. Compared to the control treatment (treatment without fertilization), with N80+PK fertilizer dosage with 60 thousand plants ha-1 the yield increased by 3.36–4.99 t ha-1. The smallest demonstrable proof, i.e. the LSD5% was 0.22 t ha-1, which means that fertilization, in each case, significantly increased the yield. When analysing the effect of fertilization in the average of the hybrids and the different plant numbers, a yield of 5.61 t ha-1 could be detected, which value was 10.12 t ha-1 with N80+PK treatment and 11.61 t ha-1 with N160+PK treatment. Thus, it can be calculated that compared to the treatment without fertilization, the N80+PK treatment increased the yield by 4.51 t ha-1, while compared to the N80+PK treatment, the N160+PK treatment increased the yield by 1.49 t ha-1. In addition to agrotechnical factors, in maize production, the impact of the crop year is specifically of high importance.
The average yield of hybrids (in the average of the different fertilizer treatments) was 6.81 t ha-1 in 2015, 11.86 t ha-1 in 2016 and 9.11 t ha-1 in 2017. When comparing the yield results against the precipitation data, it is clearly visible that the amount of rain fell in the January– October period is directly proportional to the average yield of maize. The effect of the crop year can be defined in a 5.05 t ha-1 difference in the yield.
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Effect of the plant density on different maize (Zea mays L.) hybrids yields and leaf area index (LAI) values
Published March 5, 2015
51-56

We have investigated the plant number reactions of three maize hybrids of various genotypes in a small-plot field experiment. The plant numbers were 50, 70 and 90 thousand ha-1, while the row distances were 45 and 76 cm. The experiment was set on the Látókép Experimental Farm of Centre for Agricultural Sciences of the University o...f Debrecen in four replications on calcareous chernozem soil.

The assimilation area and the leaf area index have important role in development of the crop yield. The studied three different genotype maize hybrids reached its maximum leaf area index at flowering. The maximum leaf area index increased linearly with increasing plant density. The season-hybrids reached less yield and leaf area index. According to our experimental results, we have concluded that with the decrease of the row spacing, the yield increased in the average of the hybrids. The studied hybrids reached the maximum yield at 70 and 90 plants ha-1 plant density. We determined the optimal plant number that is the most favourable for the certain hybrid under the given conditions.The higher plant density was favourable at 45 cm row spacing than 76 cm. The hybrids reached the maximum grain yield at 45 cm row spacing between 76 712–84 938 plants ha-1, while the optimum plant density at 76 cm row spacing changed between 61 875–65 876 plants ha-1.

The leaf area index values between the applied plant density for the flowering period (July 1, 24), we defined a significant differences. In the archived yields were significant differences at the 45 cm row spacing between 50 and 70, 90 thousand ha-1 plant density, while the number for the 76 cm row spacing used did not cause a significant differences in the yield. There were significant differences between the examined hybrids of yields.

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The effect of the plant density for the yield of the maize hybrids
Published May 23, 2006
50-61

In order to enchance the yield stability of maize, the effect of plant density on yields was studied on a typical meadow soil in Hajdúböszörmény between 2002-2004. In the plant density experiment, we used the method of Béla Győrffy. The plant densities applied therefore 20 to 100 thousand plants/ha by ten thousand scale. The application o...f fertilizer rates for the maize hibrids in every year were N: 110 P: 90 K: 120 kg/ha. We used a manual soiling-gun in the experiment. In every year we used plant protection techniques against monocotyledonous and dicotyledonous weeds. The harvest was done by hand. The facts were read by variancie analysis and linear regression analysis. The moisture and the temperatures were extreme in 2002, 2003, 2004. We have to mention defficiery of moisture in 2003 which is shown that the hot days number increased. After evaluating our findings we can conclude that most hybrids showed a significant correlation between increased plant density and the volume of yields. On the basis of the experiments we divided the hybrids into four groups: the first group included the hybrids suitable for increased plant density with a wide range of optimal density values; the second group included hybrids, which did not require high plant density, were capable of good individual performance and tended to grow several ears; the third group included flexible corn types, which grew longer ears in favourable years, thus yielded more; and the fourth group included the hybrids, which were sensitive to increased plant density and which showed a narrow range of optimal density values. Finally, plant density determines the yield; we have to consider optimal plant density intervals as well as optimal plant density, and we also have to place a high emphasis on the use of hybrid-specific technologies.

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Effects of the cropyear and the agronomical factors on agronomical elements of different sweet corn (Zea Mays L. convar. saccharata Koern.) genotypes in long-term experiment
Published December 16, 2012
105-110

In the crop season of 2010 (rainy year), we studied the effect of three agrotechnical factors (sowing time, fertilization, plant density) and four different genotypes on the agronomical characteristics of sweet corn on chernozem soil in the Hajdúság. The experiments were carried out at the Látókép Experimental Farm of the University of Deb...recen. In the experiment, two sowing dates (27 April, 26 May), six fertilization levels (control, N30+PK, N60+PK, N90+PK, N120+PK, N150+PK) and four genotypes (Jumbo, Enterprise, Prelude, Box-R) were used at two plant densities (45 thousand plants ha-1, 65 thousand plants ha-1). The amount of precipitation in the season of 2010 was 184 mm higher, while the average temperature was 0.8 oC higher in the studied months than the average of 30 years. Weather was more favourable for sweet maize at the first sowing date, if we consider the yields, however, if we evaluate the agronomical data and yield elements (number of cobs, cob length and diameter, the number of kernel rows, the number of kernels per row) it can be stated that the size of the fertile cobs was greater at the second sowing date due to the lower number of cobs. The largest number of fertile cobs was harvested in the case of the hybrid Enterprise (72367.9 ha-1) in the higher plant density treatment (65 thousand ha-1) at the fertilization level of N120+PK when the first sowing date was applied. The largest cobs were harvested from the hybrid Box-R (cob weight with husks: 516.7 g, number of kernels in one row: 45.7) at the lower plant density (45 thousand plants ha-1) in the second sowing date treatment. Cob diameter and the number of kernel rows were the highest for the hybrid Prelude.

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Comparative examination of a bacterium preparation (BACTOFIL® A10) and an artificial fertilizer [CA(NO3)2] on calcareous chernozem soil
Published November 3, 2010
75-80

In a small-pot experiment a bacterium preparation, Bactofil® A10 and an artificial fertilizer containing Ca(NO3)2 in different dosages were studied on calcareous chernozem soil, concerning the readily available nutrient content of soil (nitrate-nitrogen, AL-phosphorus, ALpotassium content of soil, some soil microbial char...acteristics (total number of bacteria and fungi, cellulose-decomposing and nitrifying bacteria, CO2-production of soil), and the amount of the plant biomass.
The readily available nutrient content of the calcareous chernozem soil increased due to the treatments, except for the change in the soil nitrate-nitrogen content, which did not measure up to the control due to the effect of high-dosage Bactofil.
The treatments also influenced the examined microbial characteristics of the soil positively. The artificial treatments significantly increased the total number of bacteria and the number of cellulose-decomposing and nitrifying bacteria. The low-dosage Bactofil significantly increased the number of cellulose-decomposing bacteria and both Bactofil dosage significantly increased the number of nitrifying bacteria. The measure of the soil respiration grew in all treatments, but significantly only in Ca(NO3)2 fertiliser treatments.
The quantity of the plant biomass was grew in a low-dosage Bactofil and significantly in the artificial fertiliser treatments. The highest plant biomass quantity was measured in the high-dosage artificial fertiliser treatment.
In the correlation analyses we found some medium positive correlation between the soil chemical, microbiological parameters examined, and the plant biomass in the case of both treatment-forms. 
Based on our results Ca(NO3)2 artificial fertiliser treatments on calcareous chernozem soil proved to be more stimulating regarding the
examined soil characteristics and the amount of the plant biomass, but the low-dosage Bactofil also positively influenced the majority of the
soil characteristics examined in terms of nutrient supply.

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The effect of different herbicide on the number and activity of living microorganisms in soil
Published May 23, 2006
76-82

Sustainable plant growth, considering the difficulties of weed elimination, cannot be effective without the application of herbicides. However, these chemicals have enormous ecological implications, including effects on the microbiological communities of soils. It is advisable to use herbicides that have minimal secondary effects on the environ...ment and soil-living microorganisms. In contrast, herbicides with prolonged growth stimulating or inhibiting effects are not suitable, because both types have strong influences on the number and activity of bacteria, thus causing changes in the ecological equilibrium.
Preceding small plot experiments, laboratory tests were carried out to study the effect of herbicides used in maize cultures on the number of bacteria and growth of microscopic fungi.
Substances that were observed to have stronger influences were applied in small plot experiments set up in the experimental garden of the Department of Plant Protection of the University of Debrecen. We studied the effects of four herbicides (Acenit A88EC, Frontier 900 EC, Merlin SC and Wing EC) on the microbiological properties of the soil. These herbicides were used in different concentrations in maize culture, and we investigated the effects in different soil layers.
In the laboratory experiments, we determined the total number of bacteria and microscopic fungi and examined the growth of Aspergillus niger, Trichoderma sp. and Fusarium oxysporum on peptone-glucose agar containing herbicides.
During the small plot experiments, soil samples were collected 3 times a year from 2-20 cm depth. The total numbers of bacteria and microscopic fungi were determined by plate dilution method, while the method of most probable number (Pochon method) was used to determine the numbers of nitrifying bacteria and cellulose decomposing bacteria. To evaluate the microbiological activity of the soil samples we measured carbon-dioxide release (after 10 days incubation), nitrate production (after 14 days incubation) and the concentration of C and N in the biomass.
We can summarize our results as follows:
• In laboratory experiments, herbicides caused a decrease in the number of bacteria and inhibited the growth of microscopic fungi.
• Frontier 900 EC and Acenit A 880 EC had the strongest inhibiting effect on microorganisms.
• In small plot experiments, herbicide treatment decreased the total number of bacteria and microscopic fungi.
• Herbicides caused a significant increase in the number of nitrifying and cellulose decomposing bacteria.
• Different herbicides containing the same active compound had similar influences on soil microoorganisms.
• A significant increase was observed in the physiological processes of tolerant microorganisms surviving the effects of herbicides

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Evaluation of the Green bean variety candidate BU-16
Published July 28, 2008
75-81

This study presents the results of the variety comparison trials conducted with the French bean variety candidate BU-16 on sandy soil, during two years at the Research Center of the University of Debrecen.
The outstanding characteristics of this variety candidate are the early maturity, the showy pods (yellow, straight, cylindrical cross-sec...tion „pencil bean”) and the high yield potential.
The experiments were conducted with a randomized design, with five varieties and four replications. The varieties (of which two are foreign and three are domestic) were as follows: BU-16 fj, Maxidor, Paridor, Hungold and Budai piaci. The individual plots were 2 m wide and 4 m long. The seeds were sown at a density of 30 germs per m2, with a row spacing of 50 cm.
The following parameters were taken: time of flowering, time of green maturity, plant height, height of the lowest pod above ground level, number of pods per plant, distribution of the pods by the state of development (20 plants), usable pod length (1 kg of standard crop-yield), yield per hectare based on the number of plants per plot. The experiments were evaluated statistically with Excel and SPSS softwares.
Results obtained with the variety candidate BU-16:
– The time from the emergence to green maturity is 45 to 46 days, which is short as compared with the other cultivars studied.
– Plant height is 38cm (two years average), which is among the highest ones, together with Paridor.
– The pods are set high above the ground level similarly to Paridor, the height of the lowest pod is 19 cm.
– The average number of pods per plant is 13 (two years average) similarly to Paridor and to Maxidor.
– The distribution of pod size in 2007 is as follows: 68% of the pods of BU-16 is of the standars size, which is a good rate. The value of this trait for the other varieties is 60 to 63%, except for Paridor, the value of which is similar to that of BU-16.
– The usable pod length (10 to 14 cm) is 63% in 2007 and 84% in 2006. Similar pod length rates were obtained for Maxidor, while the rate for Paridor is as high as 91%.
– The total yield and the standard yield of BU-16 is among the highest ones.
According to the results obtained and presented above, the variety candidate BU-16 is the earliest maturing among the varieties tested with high yield potential which, however, is not significantly different from that of the others. Significant differences can only be detected in plant height and the number of pods per plant. Considering the results, BU-16 is to be further tested.

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Preliminary data on the effect of semi-synthetic baits for Noctuidae (Lepidoptera) on the non-target Lepidoptera species
Published June 2, 2015
71-80

Noctuidae are one of the most important Lepidoptera groups containing dangerous pest species. Monitoring and detection of these pest species is routinely performed by traps baited with sex-pheromones. Baits that attract both males and females were developed for improved pest management. First the effectiveness of different synthetic compounds w...as evaluated. We also tested semi-synthetic baits that contained both synthetic and natural components (wine and beer). These were more attractive for moths considering species richness and abundance. Disadvantage of this increased effectiveness is that the traps catch more non target, rare and even protected species. In this study we analysed the effect of semi-synthetic baits developed for Noctuid moths containing wine on other non-target Lepidopterans. In the six sampling sites traps caught 17158 individuals of 183 Lepidoptera species. The number of Noctuidae species was 124, while their proportion was 84.4%. The traps caught 813 individuals of 9 protected and 20 valuable species, which was only 4.7% of all Lepidopterans. In contrast the mean proportion of 33 dangerous and potential pest species was 31.3% (5375 individuals). Number and abundance of both protected and pest species were affected by landscape structure. The risks of catching non-target species was higher in species rich natural and semi-natural landscape. In homogenous arable lands the number and proportion of valuable Lepidopterans was not significant.

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The effect of production area on the development of yield producing factors of maize (Zea mays L.) hybrids of different genotypes
Published February 18, 2016
67-72

Maize yield amount development is determined by the given crop year and the genotype of the applied hybrid, but beside these also by the applied agrotechnical factors, in particular by sowing technology. The development of yield amount and yield producing factors of five maize hybrids of different genotypes has been studied in a small-plot fiel...d experiment by the application of different row spacings and plant density variants. The production of the individual plants shows decreasing tendency parallel to the increasing plant density, however, this decrement is compensated by the higher number of plants per unit production area. Individual plant production is determined by the development of yield producing factors, such as the length and the diameter of cobs, just as by the thousand seed weight – that were studied in the present research work as well.

In the present research work the decreasing row spacing resulted in a yield increment of 0.67 t ha-1 (4.53%) in 2013, while in contrast in 2014 yield was decreased by 1.75 t ha-1 (14.87%). The high amount of precipitation in March was determinant in 2013: it filled up the soil water stock and balanced the negative effect of the inadequate amount and distribution of precipitation during the vegetation period for the yield. Lower extent of yield increment (0.6 t ha-1) was registered in 2014 in case of the row spacing of 76 cm than in the previous year. In case of a row spacing of 45 cm the difference between the two crop years was 3.1 t ha-1. The highest impact on the yield production factors was found in all treatment combinations in case of the applied hybrid among the three studied treatment factors. In the crop year of 2014 the effect of plant density on cob diameter and thousand seed weight could be revealed as well. In case of the cob diameter significant difference was found between the plant densities of 70 000 and 90 000 plants ha-1, just as between the populations with densities of 50 000 and 90 000 plants ha-1. In case of the thousand seed weight significant differences could be found by the application of plant densities of 70 000 and 90 000 plants ha-1. The highest values of the studied yield producing factors were measured in case of the plant densities of 50 000 and 70 000 plants ha-1; increasing the plant density to 90 000 plants ha-1 resulted in rather decreasing values.

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The effect of and interaction between the biological bases and the agrotechnical factors on maize yield
Published June 30, 2018
83-87
The effect of and interaction between the biological bases and the agrotechnical factors on maize yield In our research, we examined the effect of the hybrid, the nutrient supply, the number of plants and the abiotic factors (temperature, amount of precipitation) on the yield, crop quality and yield stability of m...aize. We devoted special attention to the natural nutrient utilization ability and fertilizer reaction of maize. The experiment took place in Hajdúszoboszló on chernozem soil, on a nearly 8 ha field. The size of one plot was 206 m2; therefore, this experiment was half-industrial. We tested six hybrids with different genetic characteristics and growing seasons.
We analysed the correlation between the nutrient supply and the yield of maize hybrids with a control treatment (treatment without fertilization) and with N 80, P2O5 60, K2O 70 kg ha-1 and N 160, P2O5 120, K2O 140 kg ha-1 fertilizer treatments. The yield increasing effect of the fertilizer also depended on the number of plants per hectare to a great extent. The number of plants of the six tested hybrids was 60, 70, and 80 thousand plants ha-1.
In 2015, the highest yield was produced by hybrid P9241 with N80+PK and 70 thousand plants per hectare. With the N160+PK fertilizer dosage, the same hybrid responded the best, followed by hybrids P9486 and DKC4717. Using the same fertilizer treatment, the 80 thousand plants per hectare population density resulted in decrease in the yield with most of the examined hybrids. In 2016, with the increase in the number of plants per hectare, even with non-fertilised treatment (control treatment), the yield could be increased in the case of each hybrid.
Averaged over the different hybrids and fertilizer treatments, applying 80 thousand plants ha-1 instead of 60 thousand resulted in 1.0 ha-1 yield increase. In 2017, the number of plants had a slighter effect. With N160+PK treatment, in most cases no significant difference can be observed. The value of LSD5%: plant number: 0.20 t ha-1, hybrid: 0.28 t ha-1, interaction: 0.48 t ha-1. With N160+PK treatment, the hybrids produced yields between 10.07 and 12.45 t ha-1. When examining the three years in the average of the number of plants, with treatment without fertilisation, the average yield of hybrids reached 7.53 t ha-1. With N80+PK treatment, this value was 9.71 t ha-1 and with doubling the fertilizer dosage, this value increased to 10.42 t ha-1. No economic profit was gained as a result of applying double dosage of fertilizer; therefore, the N80+PK dosage can be considered ideal.
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Test of the Plant Density Reaction of Genotype Sunflower Hybrids
Published December 6, 2005
113-119

In order to produce sunflower in Hungary today it is important to develop hybrid-specific cropping technologies. The ever widening number of hybrids makes the constant examination of genotypes necessary from the viewpoint of genotype-environment interactions and critical elements. Plant density as a complex factor puts strain on the pathologica...l features, yield and quality of sunflower. The experiment’s main objective is to find the optimal plant density for both the genotype and external factors.
As a result it can be stated that the optimal crop density is between 45,000-75,000 plant/ha. In 2001 the optimal density was 55,000 plant/ha. The Aréna PR and the Alexandra PR hybrids produced the greatest yields (3511 kgha-1; 3338 kgha-1). In the growing season of 2002, the yields were higher than in the previous year and the optimal crop density was 45,000-65,000 plant/ha. The best yields were produced by the Aréna PR and Alexandra PR hybrids in this year again (4102 kgha-1; 4267 kgha-1) and in 2003, 45,000-65,000 plant/ha proved to be the best crop density. The highest yield was produced by the Alexandra PR.
Analyzing the growing seasons of 2001, 2002 and 2003 it can be declared that as a result of dry climate of the three years yields were higher. It can be stated that the yield is decreased by higher than average of precipitation in the growing season.

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The effect of grazing of various cattle breeds on botanical composition of low-lying pasture in Hortobágy
Published August 29, 2017
57-63

Coenological surveys were conducted in the Hortobágy National Park (Pap-ere and Zám-puszta) in May 2015 and 2016. During the tests,a total of 40 permanent plots were analyzed on grasslands grazed by extensive cattle (Hungarian Grey) and mixed genotype intensive cattle. The presence of plant species, percentages of... total coverage of species and vegetation cover were recorded. Two habitat types were chosen according to their moisture content: wet salt marsh meadow (Bolboschoenetum maritimi) and drier salt meadows (Beckmannion eruciformis).

We compared the impact of increased number of animals (2016 years) and the low number of animals (2015 years, initial state) and the grazing exclusion on vegetations.
We tested: (i) what is the impact of grazing on the vegetation, (ii) how do species composition and vegetation charachteristics differ in the two habitat types (iii) and is there a difference in the impact of different cattle breeds (Hungarian gray, intensive beef cattle) grazing on the grasslands species composition? During the investigation we found, (i) that the greatest number of species was recorded in 2015, on the area that received moderate to intensive grazing (14.3 species per m2). Somewhat the number of species was reduced in 2016 due to more intensive grazing. The control group had the lowest number of species (11.7 species per m2). The undergrass and legumes cover significantly increased on intensive grazed lands. (ii) Our results indicate that the effects of different grazing differ in the two studied habitat types. On the drier grasslands greater number of species were found (16.2 species per m2), oppositely to the wet grassland (11.2 species per m2). The cover of the undergrasses was higher in the drier habitat than in the wet. (iii) The extensive beef cattle left a bigger number of species (16 species per m2) than the intensive beef cattle (11.4 species per m2). The grass cover was more intense on areas grazed by intensive cattle. The absolute and potential weeds cover showed a higher value on areas grazed by Hungarian Grey. Our two-year results suggest that grazing by both extensive and intensive cattle breeds can be a proper tool for the conservation management of alkali grasslands.

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Examination of plant number and sowing date in different crop years
Published March 11, 2014
79-82

We examinated three agrotechnical factors in 2011, 2012 and 2013 (sowing time, nutrient factor and plant density), as well as five different effects of genotypes on the crop of corn, on brown soil in the Hajdúság. The experiment was set next to the 47 main road in Debrecen, at the 6th kilometre stone.

In the present process...ing I would like to touch on the effects of sowing time and plant density, as I do not have the chance to present the whole experiment results here. It is true for all three years that the humidity factors differ from the long years’ average, so the genotypes had different reactions on it. According to our results we found out that the late sowing time’s result had the most successful crop yield result with 9975 kg ha-1, while examining the plant density the result of the highest plant density proved to be the best with 9967 kg ha-1.

We take the critical season in corns’ life cycle process into consideration when examining the results: June, July and August months’ humidity and temperature markers. According to the results in the tested 3 months we had 227 mm humidity with 10 days, when the average temperature was over 25 °C. The same factors in 2012 were 135.5 mm humidity with 37 days of average temperatures of 25 °C and in 2013 we recorded 102.5 mm humidity with 24 of these days.

Our goal is to help the farmers in the Hajdúság with the results of our sowing times, hybrid choice and plant density results.

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58
79
Investigation of directions of crossing in maize (Zea mays L.)
Published November 15, 2007
43-48

In Hungary, we examined eight features of twelve direct cross hybrids over a period of three years. The twelve hybrids were derived from direct and reciprocal crosses of four parental lines. We did not find significant differences in the cases of stalk diameter and leaf number in the average of 3 years in any of the hybrids. Statistically expla...inable differences in primary branches were observed in hybrids UDH5 and UDH8 and also in UDH6 and UDH11. It was evident in both instances that degrees of heterosis in reciprocal crosses far exceeded those of direct ones. High tassel branch number was dominant over the low one; consequently, parents with higher tassel numbers enforced their effects during the formation of this trait in hybrids. We experienced positive correlation (r=0.67**) between plant height and main ear height. A positive correlation (r=0.89**) was also found between the tassel length of the main axis above the lowest and the upper side branch. We observed a medium correlation (r=-0.42**) between the number of primary lateral branches and plant height. The number of primary lateral branches showed the highest heterosis. These results can be utilized in practical selection and seed production.

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19
28
The application of bentonite and zeolite for soil amelioration in acidic sandy soil
Published November 2, 2009
131-137

In a pot experiment, we have studied the effect of bentonite and zeolite in different dosages [control; 5; 10; 15; 20 g kg-1] on acidic (pHH2O=5.65) humus sandy soil. The experiment was set up in 2007 and 2008 in the greenhouse of the UD CASE Department of Agrochemistry and Soil Science. As a test plant, perennial ryegrass... (Lolium perenne L.) was used. 
In laboratory examinations, pH(H2O), pH(KCl), hidrolytic acidity, nitrate-N content, readily available phosphorus and potassium content were determined. Among soil microbial parameters, the total number of bacteria, the cellulose-decomposing bacteria, the carbon-dioxide production, the microbial biomass-C content of soil, and the saccharase enzyme activity were measured. In the experiment the biomass of the test plant was determined.
The effect of bentonite and zeolite in different dosages can be summarized as follows:
− The pH increased under the effect of low dosages. With the increasing of the pH the hydrolytic acidity - at the bentonite treatments significantly – decreased. 
− Regarding the readily available nutrient content of the soil, low and medium dosages proved to be effective. High dosages of bentonite treatments reduced the nitrate-N content, the readily available phosphorus, and potassium content of soil, by zeolite treatments the high dosages reduced the nitrate-N content of soil. 
− Regarding the measured soil microbial parameters in both treatments low and medium dosages proved to be also effective, but the high dosages didn’t cause decreasing at the total number of bacteria, and by zeolite treatments the biomass-C content of soil.
− Also the bentonite and zeolite treatments enlarged the biomass of the test plant. We experienced significant increasing by bentonite treatments by the effect of medium and high dosages, while in zeolite treatments only the high dosage caused significantly increasing in plant biomass. The largest dosages decrease the plant biomass. 
− Under the statistical analysis we found many medium and tight correlation between the studied parameters. 

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23
32
Microbiological and Chemical Characterization of Different Composts
Published May 11, 2003
106-111

Composting of agricultural waste is considered particularly important from the point-of-view of environmental protection. Degradation of organic substance results in a significant reduction of waste volume.
The end product of the composting process, mature compost, can be used as soil coverage against excess loss of wastes, for mulching, for... organic manure etc. The problem of composting has come into limelight in environmental studies and in agriculture.
The quality of the mature compost is determined by physical, chemical and biological parameters of the composting process which, in turn, depend on initial composition of the raw materials, the technology, e.g. regular mixing and moistening and on environmental factors. Quality is the key question in compost use.
We studied the composting process in compost windrows of different raw material composition. We measured temperature, humidity content, pH, organic substance content, nitrogen and carbon content.
We counted the number of bacteria, microscopic fungy, ammonifying and cellulose decomposing microorganisms. We directed the composting process with turning weekly (to provide oxygen) and watering (to provide humidity content 40-60%).
We set up windrows of 1 m3 volume from dry plant substances (cornstalk, pea straw, tomato stalk and crop, weeds) and cow manure not older than 1 week. The cow manure was used at ratios of 0%, 35%, 50%, 65% and 100%, respectively.
We measured changes in compost temperature relationship with outside temperature until they were almoust the same. Humidity was 40-60% in most cases.
At the beginning of the process, pH was slightly acidic-neutral; it later becomes neutral-slightly alkaline (pH: 6.93-8.02) as ammonia is liberated from proteins.
At the end of the process, pH decreased again, due to humification.
Organic substance content decreased as microorganisms mineralized them. Organic carbon content decreased gradually due to microorganisms used it as an energy.
Total nitrogen content increased until middle of july and decreased gradually until than.
The carbon/nitrogen rate were higher in the beginning, it decreased until july-august and increased by smaller degree until end of the process.
The number of bacteria was higher in the first three weeks and between june-september. The number of cellulose degrading bacteria was the highest in the first three month, the number of ammonifying bacteria was the highest from the end of may until sepember.
The number of microscopic fungy was significant in the second part of process, after july.

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18
31
The Evaluation of Grazed Grasslands on the Hortobágy
Published May 11, 2003
50-54

The sward composition of different grasslands on Puszta Hortobágy has been developed according to prevailing abiotic and biotic factors. The abiotic conditions have been more or less constans for long periods of time, and the abiotic factors are determined by ecological conditions (climate, soil, topography). Among biotic factors grazing of he...rbivores was important in the development of Hortobágy grasslands for centuries (Sipos and Varga, 1993). Result of three-year investigations on the sward composition of grasslands utilised in different ways are presented. Data on ground cover, number of plant species, representation of different plant groups (grasses, sedge and bent-grass, herbs, legumes) and weeds are reported from six different grazed grassland types from Puszta Hortobágy.
In 1999-2001 a sward composition survey was conducted. Sample areas of 2x2 m2 were marked out in three replicates: on temporarily waterlogged grassland grazed by cattle (A), on dry grassland grazed by cattle (B), on dry grassland grazed by sheep (C), on dry grassland grazed by buffaloes (D), on dry grassland grazed by buffaloes and geese (E), on dry grassland cut for hay in May then grazed by geese (F). On the sample areas sward composition of grasslands was estimated according to Balázs (1949).
The average ground cover of different grasslands ranged between 60 and 100% (Table 2). The lowest value was found for grasslands C and E, which are grazed by sheep (C) and buffaloes and geese alternately (E). In these grasslands were some open spaces, on the other grasslands completely closed swards covers were observed.
The species diversity of these natural grasslands are high (Table 2). The grassland F, which were cut for hay in May had the lowest diversity (17-21). The highest number of species was found on grassland A and B (32-51), on other grazed grasslands (C, D, E) had 29-48 species.
The different plant groups had different representation in the total ground cover (Table 3). The number of herbs was always higher then that of grasses, but the cover of herbs was lower then that of grasses. The legumes and the sedge and bent grasses were present in high abundance in grassland A, but in the other grasslands were not.
The composition of herbs should be a warning for future utilisation systems on some grasslands of Hortobágy. Some species of herbs, e.g. Achillea millefolium, Artemisia vulgaris, Carduus acanthoides, Cirsium arvense, Cirsium vulgare Eryngium campestre, Galium mollugo, Galium verum, Ononis spinosa, Rumex crispus, Verbascum phlomoideus, Phragmites australis can be invasive on short grasslands.

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24
29
Effect of genotypes and cropyear on thedifferent cultivation parameters of asparagus (Asparagus officinalis L.)
Published February 25, 2014
31-34

The experiments were performed in the Research Institute of Nyíregyháza Research Institutes and Study Farm, Centre for Agricultural Sciences University of Debrecen of 1500 m2 asparagus plantation. The asparagus was planted in 2011. We were determine the number of shoots, plant height and fold thicknes of asparagus hybrid. We can co...ntinuously monitored the growing parameters of asparagus. The harvest of asparagus was started in 2013, so we were able to measure to quantity. The weather was characterized by warm and matched precipitation in the growing season (April–July) in 2011 and 2012. Contrarily, the weather was very hot and dry after the late frost in 2013. The Vitalim produced the largest quantity, then the Cumulus and the end of Grolim hybrid. Number of shoot and plant height sequence is identical to the previous one. The Grolim asparagus hibrid has the largest basal diameter.

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105
99
Using research findings in precision maize production
Published November 13, 2012
227-231

The effect of crop production factors on maize yield are examined on chernozem soil in a more than 30 year old long-term experiment on the Látókép Experiment Site of the Centre for Agricultural and Applied Economic Sciences of the University of Debrecen. The aim of research is to evaluate the effect of fertilisation, cultivation, plant numbe...r, genorype and irrigation. The analysis of the data in the database of the examined period makes it possible to evaluate the effect of maize yield, as well as that of the crop production factors and the crop year, while the correlations and interactions between these factors were also examined. During the examination of the cultivation treatments, it was concluded that the highest yield was obtained as a result of autumn ploughing, but its effect largely differs in the irrigated and the nonirrigated treatments. Based on our examinations, strip cultivation should be applied periodically (e.g. strip – strip – ploughing – loosening) in areas with favourable soil conditions free from compacted layers. 
In years with smaller, average precipitation supply or when the precipitation was higher than average, higher plant numbers were more favourable. Under drier conditions, but especially in several consecutively dry years, a lower plant number can be recommended which is not higher than 60 thousand per hectare. In the case of favourable water supply, 70-80 thousand plants per hectare can be  used. The yield increasing effect of fertilisation was significant in the case of both non-irrigated and irrigated conditions, but it was much more moderate in the non-irrigated treatment. The extent of weed coverage was significantly affected by the previous crop. In the case of a favourable previous crop (wheat), the weed coverage was significantly lower than after an unfavourable previous crop (maize). In the case of the same previous crop (maize), the extent of weed coverage was mostly determined by the crop year and the extent of precipitation supply. Irrigation is not enough in itself, because if it was not accompanied by intensive nutrient management, yields started to decline.
The results of researhc, development and innovation contributed to the technological method which makes it possible to apply locally adjusted sowing seed, fertiliser and pesticide in a differentiated way, as well as to change the method of operations within the given plot.

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62
76
Study of plant physiological parameters in winter oilseed rape (Brassica napus var. napus f. biennis L.) production on chernozem soil
Published February 18, 2016
111-115

We made plant physiology examinations in Arkaso winter oilseed rape hybrid substance: relative chlorophyll content (SPAD) and leaf area index (LAI) measurements. The experiment was set in University of Debrecen Agricultural Sciences Center at Látóképi Experimental Station in four replications, in two different sowing times (I. sowing date on... 08/22/2014 and II. sowing date on 09/09/2014 sowing againhappened because of the incomplete germination in the second subtance 01/10/2014) Three different plant density 200, 350 and 500 thousand ha-1, under the same nutrient supply, 45 cm row spacing. The experiment was green crop of winter wheat. The relative chlorophyll content (SPAD) and leaf area index (LAI) measurements were made in seven different times. We measured the maximum value of chlorophyll content in the first sowing time at 500, and the second sowing time at 350 thousand ha-1 plant density. The measurement results proved that there was a linear relationship between the number of plants and the LAI. The maximum leaf area index values we measured in both the sowing time at 500 thousand ha-1 reached.

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77
79
Technological development of sustainable maize production and its effect on yield stability
Published September 5, 2018
379-388
In 2015 and 2016, we examined the effect of NPK nutrients, sowing date and plant density on yield on typical meadow soil. The amount of precipitation was 282.0 mm in 2015 (January–September), 706.0 mm in 2016 and the 30-year averageis 445.8 mm.
Agrotechnical factors:
– Experiment a)
   &n...bsp;       5 Dow AgroSciences hybrid with three sowing dates and three plant densities
– Experiment b)
In 2015 eight, in 2016 ten hybrids with different genetic characteristics and growing seasons, with control (without fertilization), N80+PK and N160+PKtreatments, five plant densities (50–90 thousand) with 10 thousand plants difference between the different densities.
In a drought year, we reached the higher yield in the earlier sowing date and with the lower lower plant density of 70 thousand plants ha-1-. The maximum yield, depending on the agrotechnical factors, was 10–12 t ha-1 in 2015, while in 2016 it was 14–16 t ha-1. Yield stability can be increased using hybrid-specific cultivation techniques.
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75
47
The role of green manure crops in Hungarian plant production
Published June 30, 2018
49-53

According 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 unfavo...urable 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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