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  • The effect of plant density on maize yield in average and extremely dry years
    7-16
    Views:
    86

    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.

  • Correlation between the weather in 2017 and the productivity of maize
    89-93
    Views:
    153
    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.
  • Effect of tillage practices, fertilizer treatments and crop rotation on yield of maize (Zea mays L.) hybrids
    43-48
    Views:
    167

    This research was conducted at the University of Debrecen Látókép Research Station and is part of an ongoing long-term polyfactorial experiment. The impact of three tillage systems (Mouldboard plowing-MT, Strip tillage-ST, Ripper tillage-RT) and two levels of fertilizer treatments (N80 kg ha-1, N160 kg ha-1) along with a control (N0 kg ha-1) on the yield of maize hybrids (Armagnac- FAO 490 & Loupiac-FAO 380) cultivated in rotation with winter wheat was evaluated during a two-year period (2017–2018).

    Amongst the three tillage treatments evaluated, ripper tillage (RT) had the highest average yield (10.14 t ha-1) followed by mouldboard tillage (MT) and strip tillage (ST) with 9.84 and 9.21 t ha-1 respectively. Yield difference between RT and MT was not significant (P>0.05), as compared to ST (P<0.05). Soil moisture content varied significantly with tillage practices and was highest in ST, followed by RT and MT (ST>RT>MT). Yield of RT was 7–9% higher than MT in monoculture plots, while MT reign superior in biculture plots (monoculture: RT>MT>ST; biculture: MT>RT>ST).

    A positive interaction between tillage and fertilization was observed, with higher yield variation (CV=40.70) in the non-fertilized (N0) plots, compared to those which received the N80 (CV=19.50) and N160 kg ha-1 (CV=11.59) treatments.

    Incremental yield gain from increase fertilizer dosages was significantly higher in monoculture, compared to biculture. There was no significant difference in yield between N160 and N80 in the biculture plots (12.29 vs 12.02 t ha-1). However, in monoculture plots, N160 yield was 23% higher than the N80 kg ha-1 (N160=11.74 vs N80=9.56 t ha-1).

    Mean yield of maize in rotation with winter wheat was 28% (2.47 tons) higher than monoculture maize. The greatest benefit of crop rotation was observed in the control plots (N0) with an incremental yield gain of 4.39 tons ha-1 over monculture maize (9.92 vs 5.43 t ha-1).

    Yield increased with higher fertilizer dosages in irrigated plots. Fertilizer application greatly increased the yield of maize and accounted for 48.9% of yield variances. The highest yield (11.92 t ha-1) was obtained with N160 kg ha-1 treatment, followed by N80 kg ha-1 (10.38 t ha-1) and N0 kg ha-1 (6.89 t ha-1) respectively.

    Overall mean yield difference between the two hybrids was not statistically significant, however, yield of FAO 380 was 3.9% higher (9.06 vs. 8.72 t ha-1) than FAO 490 in monoculture plots, while in biculture plots, FAO 490 was 4.1% higher than FAO 380.

    Average yield in 2018 was 13.6% (1.24 t ha-1) higher than 2017 for the same set of agrotechnical inputs, thus, highlighting the significant effect of cropyear.

    Armagnac (FAO 490) cultivated in rotation with winter wheat, under ripper tillage and N80 kg ha-1 is the best combination of treatments for optimum yield.

  • The Influence of Cropyear on the Yield and Yield Safety of Different Sunflower Hybrids
    68-73
    Views:
    99

    The 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.

  • The examination of the agronomy, the amount of yield, and the yield stability of winter wheat varieties
    61-72
    Views:
    81

    Our research was carried out at University of Debrecen Centre for Agricultural Sciences Faculty of Agriculture Institution of Plant Sciences Látókép Research Institute through the breeding year of 2003/2004, 2004/2005 and 2005/2006 using cherrnozem soil. In our research we tested 14 chosen autumn wheat varieties during the three crop years.
    The different varieties showed very dissimilar ability of resistance against diseases through the three crop years. We could observe both susceptible and resistant varieties. Susceptible varieties got diseases even in favourable crop years. The observed winter wheat varieties showed higher susceptibility against helminthosporium (21.8%) and leaf rost (16.4%). Among the 14 varieties we experienced the least susceptibility in the case of ‘Gaspard’ and ‘GK Kalász’. The research showed that the disease of fusarium undoubtedly depends on the features of the crop year.
    In terms of stem solidity we experienced big differences. Among all the observed winter wheat varieties the mid-late ripening ‘Gaspard’ showed the best results in the average of the three years, only 5.3% was beaten down.
    The three ripening group of the winter wheat showed the following average yield in the average of three years: 7065 kg/hectare (early ripening varieties), 7261 kg/hectare (late ripening varieties), 6793 kg/hectare (mid-late ripening varieties). Among all the observed varieties the early ripening ‘Flori 2’ produced the biggest yield (7692 kg/hectare).
    During the three crop years we reached very different amounts of yield which means that weather conditions had a telling affect on yield. In 2004 we reached an excellent average yield in all the tree  breeding groups because of the favourable weather conditions. In 2005 we had a moderate amount of yield because of the unfavourable weather conditions of winter. The year of 2006 showed the smallest amount of yield which is due to the fact that the plant grew less thick than usually.
    There were significant differences among the observed varieties in the term of yield, which can be attributed to dissimilar biological basics.
    One of he most important questions is the yield stability of the varieties. We had extremely different results at this field. Speaking in general terms we can state that both weather conditions and genetical abilities have a determining effect on yield. In the case of winter wheat varieties the rate of yield fluctuation was quite big, moving in the interval of 33.7-70.3%. Among all the observed varieties ‘Gaspard’ showed the best yield stability (33.3%). 

  • Correlation analysis of relative chlorophyll content and yield of maize hybrids of different genotypes
    211-214
    Views:
    116

    In 2021, correlation between relative chlorophyll content and yield in three maize hybrids of different genotypes was examined. The data were collected at the Látókép Experimental Station of the University of Debrecen located on the Hajdúság loess ridge in Hungary. The soil of the small plot field strip plot trial, which was set up in 2011, was calcareous chernozem. Apart from the control treatment (without fertilisation), N fertiliser is applied in the form of base and top dressing. The base fertiliser containing 60 and 120 kg ha-1 N of nutrient applied in spring was followed by top dressing containing +30–30 kg ha-1 N in V6 and V12 phenophases. SPAD values measured at different phenological stages of the growing season increased by an average of about 28% up to 10 leaf stage for all three hybrids. In the pre-silking period (Vn), the relative chlorophyll content decreased by 8% on average. After an average increase of 14% in the tasselling and silking period, SPAD decreased by an average of about 29% at full maturity (R6).

    For the different fertiliser treatments, higher N doses resulted in higher yields. In the basal fertiliser treatment, the A 60 N dose resulted in an average 34% increase in yield, and the A 120 N dose resulted in an average 94% increase in yield compared to the control. The 60 kg ha-1 N basal fertiliser (A60) increased in the V6 phenophase with an additional 30 kg ha-1 N resulted in an average yield increase of 26%. When 120 kg ha-1 N of basal fertiliser (A120) was increased by an additional 30 kg ha-1 N in the V6 phenophase, only the Merida hybrid showed a significant yield increase (7%). No further yield increase was observed when V690 and V6150 treatments were increased by an additional 30 kg ha-1 N in the V12 phenophase. The yield of the Armagnac hybrid decreased by almost 20%, the yield of Fornad by 3% and the yield of Merida by 1%.

  • The effect of NPK fertilization and the number of plants on the yield of maize hybrids with different genetic base in half-industrial experiment
    103-108
    Views:
    179

    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, this it was a halfindustrial experiment. 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. Yield increasing effect of the fertilizer also depended on the number of plants per hectare at a great extent. The number of plants of the six tested hybrids was 60, 70, and 80 thousand plants/ha.

    In Hajdúszoboszló, in 2015 the amount of rainfall from January to October was 340.3 mm, which was less than the average of 30 years by 105.5 mm. This year was not only draughty but it was also extremely hot, as the average temperature was higher by 1.7 °C than the average of 30 years. In the critical months of the growing season the distribution of precipitation was unfavourable for maize: in June the amount of rainfall was less by 31mm and in July by 42 mm than the average of many years.

    Unfavourable effects of the weather of year 2015 were reflected also by our experimental data. The yield of hybrids without fertilization changed between 5.28–7.13 t ha-1 depending on the number of plants.

    It can be associated also with the unfavourable crop year that the yield of the six tested hybrids is 6.33 t ha-1 in the average of the stand density of 60, 70 and 80 thousand plants per hectare without fertilization, while it is 7.14 t ha-1 with N80+PK fertilizer treatment. That increase in the yield is only 0.81 t ha-1, but it is significant. Due to the especially draughty weather the yield increasing effect of fertilizers was moderate. In the average of the hybrids and the number of plants, increasing the N80+PK treatment to N160+PK, the yield did not increase but decreased, which is explicable by the water scarcity in the period of flowering, fertilization and grain filling.

    The agroecological optimum of fertilization was N 80, P2O5 60 and K2O 70 kg ha-1. Due to the intense water scarcity, increased fertilization caused decrease in the yield. As for the number of plants, 70 000 plants ha-1 proved to be the optimum, and the further increase of the number of plants caused decrease in the yield.

  • Evaluation of the yield and baking quality of winter wheat (Triticum aestivum L.) varieties in different cropyears
    95-100
    Views:
    105

    We have investigated the effect of the cropyear, the genotype, the nutrient supply and their interactions on the yield and the quality parameters of three different winter wheat genotypes in three different cropyears. The most disadvantageous influence on the yield averages was caused by the moist weather of 2010, when yield results fell behind the mean of the two other examined years and the nutrient optimum was around low doses. The optimal cropyear turned out to be the ordinary 2011, the best yield results were experienced during this cropyear. Although the drier periods in 2012 decreased the yield values, the varieties could realize high yield maximum values. Considering the yield results, Genius turned out to be the best variety. In respect of the quality traits, 2010 turned out to be the best cropyear in case of all the three varieties. Despite the dry weather of the spring of 2012, the precipitation fell during flowering and ripening phases had positive impact on the grain-filling processes and contributed to the development of better quality. As a consequence of the significantly lower amount of precipitation during the generative phenological phases, the worst quality parameters were realized by the varieties in 2011.

     

    In respect of crop year effect, 2010 was unfavourable for the amount of yield, but the most beneficial for the quality. 2011 was the most advantageous for the yield amounts but disadvantageous for the quality parameters. Although in 2012 extreme crop year effects were experienced after each other (dry and warm spring, moist and warm summer), the yield average and quality trait values were close to the yield averages of 2011 and quality parameters of 2010. Analyzing our results we can state that the average crop year was favourable rather for the yield. The appropriate amount of precipitation during the whole 2010 and that during the generative phenophases in 2012 favoured the development of good quality.

    Consequently, the appropriate amount of precipitation is essential for the development of good quality during the grain-filling period. The negative crop year effects were only compensated but not eliminated by the good nutrient supply. Genius achieved excellent yield averages but performed worse quality parameters than Mv Toldi, whose quality parameters were outstanding but the yield averages fell slightly behind those of Genius. Considering the yield results, the variety Genius turned out to be the best, while Mv Toldi was the best in quality.

  • The effect of the sowing time on the yield and oil content of sunflower (Helianthus annus L.) in different crop protection models
    57-61
    Views:
    134

    The field research was carried out at the experimental farm of the University of Debrecen at Látókép on calcareous chernozem soil in Hungary. We examined the effects of the sowing time and the fungicide treatment on the yield, oil yield and oil content of two different genotypes of sunflower hybrids (NK Ferti, PR64H42) in 2012 and 2013. We applied three different sowing times (early, average, late) and two different treatment levels of fungicides (control =no fungicides applied, double fungicide protection).

    During our research, we received better results in 2013 than in 2012. The application of different planting times affected the yield and oil yield production and the oil content as well. The optimal circumstances for yield and oil yield production were provided by late planting in 2012, while by average planting time in 2013. The highest oil yield results were reached by late plating in both years (except for hybrid PR64H42 in the double treated parcels where average plating time turned out to be more effective). The correlation between the plating time, the yield and oil yield production and the oil content was strong in 2012 (r=0.600**, r=0.639**, r=0.590**). On the other side, in 2013, the correlation was medium between the planting time, the yield production and the oil content.

    We applied Pearson’s correlation to analyze the effect of the double fungicide treatment on the yield and oil yield production (2012: r=0.498**, r=0.407**). These results were better in 2013 (r=0.603**, r=0.623**), besides, the double fungicide treatment also increased the oil content (r=0.315**).

  • Effect of agrotechnical factors on the yield of the Grolim asparagus (Asparagus officinalis L.) hybrid on acidic sandy soil
    43-48
    Views:
    215

    Research of blanched asparagus has begun at the University of Debrecen Institutes for Agricultural Research and Educational Farm Research Institutes of Nyíregyháza in 2011. Establishment of the plantation took place in May 2011. The Grolim hybrid was used in the trial, 16 medium plot trial area has been formed under field conditions, with four repetitions and 36 m2 plot size. In the course of our studies, the effect of different nutriment supply methods (untreated, manure, sheep manure compost, fertilizer) has been analysed on the spear yield of the Grolim asparagus hybrid between 2013 and 2017.

    In our studies, the beginning of vegetative growth has been recorded upon the constant presence of 10 °C of average soil temperature in the case of the Grolim asparagus hybrid. The beginning and length of spear harvesting are both influenced by the time and dynamics of initial development in spring. During the analysed period, the dates of spear harvesting were various, the earliest being on 23rd March, 2014 and the latest on 23rd April, 2015; the rest of the three years have been varied within this one month interval. The total of heat units required for the vegetative development of spears has been determined; it provides important information for cultivation practice.

    Spear yields turned out to be hectic during the analysed period. In 2013 and 2014, yields have surpassed the amount of 50 kg/harvest period/plot in the case of every treatment version. However, in 2015 a significantly lower specific yield has been recorded due to the unfavourable weather conditions in spring; a yield decline of nearly 50% was recorded in the case of the control treatment compared to the previous years. Yield was also lower in the rest of the fertilization treatments compared to 2014; however, in these cases, the degree of yield decrease was around 5–10%, which suggests the yield stabilising effect of fertilization. In 2016, a slight yield increase was measured in comparison with the base year. In 2017, there was a decline of yield in the control treatment; however, the different fertilization treatments resulted in yield increase as compared to previous years.

    On the basis of our studies, it is clear that the best yield results have been provided by the artificial fertilization treatment in all of the five analysed years. It was followed by the sheep manure compost and manure treatments in terms of their effect on spear yield. During the three harvesting periods, the lowest yield on acidic sandy soil was recorded in the case of the control treatment. The most remarkable effect of nutriment treatments has been realised in terms of the decreased deviation of yield results, which perfectly represents the yield stabilising effect of nutriment supply in the case of perennial crops – asparagus – as well, even on a poor nutriment supply characteristic sandy soil.

  • Examination of the Effect of Cropyear on the Yield Potential and Yield Stability of Winter Wheat Varieties
    62-67
    Views:
    102

    Variety selection is one of the most important, determinative elements of sustainable winter wheat production. Yield potential, and yield stability are the most important elements in the variety selection of winter wheat, but baking quality parameters play an important role, too.
    Several winter wheat varieties were tested for yield and yield stability on chernozem soil in the Hajdúság (in the eastern part of Hungary), in the 2001-2002-2003-2004 cropyears. The management factors were the same for all cropyears. 15 varieties in early the maturity group, 14 varieties in the middle maturity group and 4 varieties in the late maturity group were tested in the above mentioned cropyears. The climatic conditions were average in 2001, dry in 2002, extremely dry in 2003, and very favourable in 2004.
    We obtained 5298-6183 kgha-1 yield from early maturity varieties, 5683-6495 kgha-1 from middle, 5694-6031 kgha-1 from late ones in the average of four years. The cropyears had strong influence on the yields, even on chernozem soil, and were characterized by excellent water – and nutrient – husbandry. Averaging of cropyears and genotypes, we obtained 6984 kgha-1 in 2001 (average cropyear), 5452 kgha-1 in 2002 (dry cropyear), 3120 kgha-1 in 2003 (extremely dry cropyear) and 8400 kgha-1 in 2004 (optimum cropyear), respectively. The yield differences between the minimum and maximum yields were 885 kgha-1 in early varieties, 812 kgha-1 in middle and 337 kgha-1 in late maturity varieties, respectively. The varieties characterized by high yield potential and the varieties characterized by good yield stability were different, so in variety selection we have to take both genetic traits into consideration. There were positive, significant correlations among the yields of winter wheat varieties (early, middle, late), the temperature of spring months. (March-April), and the rainfall of spring months (March-April) (R2=0,703**-0,768** and R2=0,681**-0,749**, respectively). We found a high negative correlation between the temperature of early summer months (May-June) and the yields of wheat varieties (R2= -0,856**- -0,918**).
    According to the results of our experiment, it is very important to harmonize yield potential and yield stability in the variety selection of winter wheat.

  • Examination of the population density and sowing date of different maize genotypes in the Hajdúság region
    111-115
    Views:
    116

    The experiment was carried out 6 km from Debrecen, next to the main road 47 on a homogeneous field on brown forest soil. Five corn hybrids were tested in the trial (DKC 4795, DKC 4995, KWS Kornelius, NK Cobalt, PR37 N01) at three different sowing times (early – 5th April, average – 21st April, late – 10th May). At each sowing time, three different plant densities were applied (modest – 58 500 plants ha-1, average –70 200 plants ha-1, high – 82 300 plants ha-1). The agrotechnics applied
    in the experiment satisfied the requirements of modern corn cultivation.

    In the study, the best yield result was achieved with the early sowing time out of the three examined sowing times (11 315 kg ha-1), which was significantly different (LSD5%=495 kg) from that of the average sowing time (10 690 kg ha-1), however, there was no statistically justifiable difference between the yield results of the early and the late sowing times. There was a significant difference also between the average and late sowing time. Our results indicate that the different sowing times resulted in a different flowering times. Consequently, the stands of early and late sowing time reached this critical stadium of growth under proper climatic circumstances (precipitation: 39 mm and 136 mm, average temperature at flowering: 18.1 oC and 20.3 oC), while flowering in the case of the average sowing time of 21st April was in the first half of July and the average temperature at flowering was warmer (23.2 oC) with only 10 mm precipitation.
    In the experiment, the plant density response was also examined. According to the measured data, four of the five hybrids responded badly to the increasing plant density. We found that the plant density of 58 500 plant ha-1 gave the largest yield results (DKC 4995 11 794 kg ha-1 – NK Cobalt 10 998 kg ha-1, average of five hybrids: 11 430 kg ha-1), while the lowest yields were obtained at the plant density of 82 300 plant ha-1 (KWS Kornelius 11 037 kg ha-1 – NK Cobalt 10 019 kg ha-1, average of five hybrids 10 720 kg ha-1). The difference between the two plant densities was significant (LSD5%=494 kg), however, the 70 200 plant ha-1 plant density did not show any statistical difference from neither the 58 500 ha-1 nor from the 82 300 plant ha-1 stands. When examining the data of the hybrids separately, we found that there was a significant difference between the average yield of the lowest and highest plant densities only in the case of three (DKC 4795, DKC 4995, NK
    Cobalt) out of the five hybrids (DKC 4795: 11 757 kg ha-1 – 10 857 ha-1 where LSD5% =816 kg; DKC 4995: 11 794 kg ha-1 – 10 738 kg ha-1 where LSD5%=853kg; NK Cobalt: 10 998 kg ha-1 – 10 019 kg ha-1 where LSD5%=630 kg ha-1), while a  significant difference between the second and third plant densities was observed only in one case (DKC 4995: 11 726 kg ha-1 – 10 738 ha-1 where LSD5%=853 kg). In all other cases, there was no statistical difference between the different
    plant densities.

  • Effect of Ferilizer on the Yield of Maize (Zea mays L.)
    40-46
    Views:
    115

    The effect of fertilization on the yield of maize was examined on chernoem soil with lime deposits at the experimental station at Látókép of the Center for Agricultural Sciences, University of Debrecen. The yields of maize were evaluated using quadratic regression function, in three years – between 2000 and 2002 – in non-irrigated and irrigated treatments. After calculating the regression equations, by derivation of the functions, we have determined the amount of fertilizers needed for maximum yield.
    In the non-irrigated treatments, maximum yield and the active substance amount of fertilizer was as it follows: in 2000, yield of 9,133 t/ha with the application of 384 kg/ha mixed active substance, while in 2002 a yield of 6,289 t/ha with the application 236 kg/ha NPK active substance was achieved. In 2001, due to the favourable precipitation, a yield of 9,864 t/ha was achieved with the application of 245 kg/ha fertilizer. In the case of maximum yield, compared to the unfertilized control, the yield increase was 2,5-5 t/ha. The average increase for 1 kg of NPK fertilizer was 13-19 kg.
    We also determined the necessary fertilizer dosage for maximum yield in irrigated treatments. In 2000, 10,003 t/ha with a dosage of 423 kg/ha, in 2001, 11,542 t/ha with a dosage of 277 kg/ha and in 2002, 8,596 t/ha of maximum yield could be achieved with a fertilizer treatment of 277 kg/ha in the examined three years. The yield increase, in irrigated treatments, varied between 3,9-5,9 t/ha so it was greater than in the case of non-irrigated experimetal plots. The yield increase for 1 kg fertilizer varied between 12-21 kg.

  • The effect of crop year and agrotechnical factors on the yield of various maturity groups of Limagrain maize hybirds
    19-23
    Views:
    134

    The 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.

  • The effect of and interaction between the biological bases and the agrotechnical factors on maize yield
    83-87
    Views:
    147
    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 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.
    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.
  • Evaluation of reaction to plant density of sunflower hybrids by regression and Kang’s stability analysis
    101-109
    Views:
    92

    The world production area and the total production of sunflower has significantly been growing. The harvested yield was 23.4 and 21.1 million ha in 2005 and 2001, respectively. The total sunflower seed production has also unexpectedly increased.
    Although sunflower is produced on lower quality soils in Hungary, in 2005 the average harvested yield was 2.43 t ha-1, which was the highest in the world. 
    Sunflower is a typical commercial plant and fits well in the crop structure. Since in terms of acreage the most significant crops are corn and cereals, the partial monoculture cultivation cannot be avoided. Sunflower production is a way to eliminate this problem, therefore it has an important role both in cultivation and ecological points of view.
    Accordingly, sunflower has an important role in reducing the monoculture cultivation of some plants, as well as increasing biodiversity. Sunflower well adapts to Hungary’s climatic conditions and its production is easily practicable in our country.
    The reaction of sunflower hybrids on crop density change is different. Some hybrids are more some are less sensitive to this parameter. In different crop years, the crop density optimums of the different genotypes are also different. In Hungary, the yield and quality is primarily determined by fungal infections, while viruses and bacteria are less important.
    The research was conducted at the Látókép farm and Regional Research Institute of the University of Debrecen, Centre of Agricultural Sciences. The research institute is situated by Road 33,15 km from Debrecen in the Hajdúság. The duration of the experiment was seven years, 10 hybrids were examined in each year.
    Two hybrids used every year, Aréna/PR and Alexandra/PR hybrids were tested by Kang’s stability analysis. We found that Alexandra/PR was most balanced at every levels of crop density. Both hybrids performed most stable yield at 65000 ha-1 crop density level and less balanced at 35000 ha-1 crop density level. As a result of improved environmental conditions, the yield increase of Aréna/PR was higher than that of Alexandra/PR.
    Our regression analysis found that the maximum yield of Lympil, Louidor, Hysun 321, PR63A82 and PR64A63 hybrids were harvested at 47000-60000 plant ha-1 crop density level. The statistical analysis showed that the highest yield was harvested from Lympil and Hysun 321. As regards the crop yield, the most stable hybrids were Louidor and Lympil. The optimum crop density interval of Rigasol/PR and Larisol (58000 plant ha-1) was wider than that of Diabolo (46000 plant ha-1). The maximum yield of Larisol was higher at the optimal crop density level. As regards yield, Diabol was the most stable hybrid.
    The statistical analysis on the stability of the yield of Alexandra/PR and Aréna/PR showed that Aréna/PR is more stable, and its optimal crop density level is lower than that of Alexandra/PR.

  • The effect of sowing time on the yield and the variance of the seed moisture content a harvest of maize (Zea mays L.) hybrids
    39-49
    Views:
    93

    Sowing time is an important crop technology element of maize. We studied the effect of this factor on the growth and production of maize in an experiment carried out near Hajdúböszörmény, in 2003 and 2004, and near Debrecen, in 2005.
    The soils of the experiments were humic gley soil and chernozem. Weather in both years differed greatly. 2003 was drought. Neither the distribution, nor the quantity of the precipitation were suitable in the growing season for maize. This fact basically determined the results.
    In 2004 and in 2005, there were favorable and rainy seasons. The distribution and quantity of precipitation were suitable between April and September. The average temperature was also suitable for maize.
    In 2003, we tested seven hybrids at four sowing times. Hybrids with a shorter vegetation period gave the highest yield at the later sowing time, while the hybrids with a longer vegetation period gave them at the earlier sowing time. The yield of PR34B97, PR36N70, PR36M53 hybrids were the best at every sowing times. The moisture loss of hybrids in the late maturity group was faster in the maturity season, but the seed moisture content was higher than the hybrids with early sowing time. The seed moisture content was very low due to the droughty year. In two hybrid cases, this value was higher than 20% only at the fourth sowing time.
    In 2004, we examined the yield and seed moisture contents of nine hybrids. In the favorable crop year, the yield of every hybrid was the highest at the second and third sowing times. Yields of PR34H31 and PR38B85 hybrids were significant. The seed moisture content at harvest was higher than the previous year, due to the rainy season. In the case of hybrids sown later, this value was higher by 30%. However, we noticed that this value was lower at the earlier sowing time, than at the later.
    In 2005, we applied three sowing times. Unfortunately, the results of the third sowing time could not be analyzed, due to the low plant density. The yield of the six hybrids varied from 12 to 14 t/ha at the first sowing time. At the second sowing time, the yields fluctuated and each hybrid had the lowest yield, except the PR37D25 hybrid. At the latest sowing time, the yield of the PR34B97 hybrid was the lowest. However, this low yield was due to damage from the Western corn rootworm (Diabrotica virgifera) imago. The moisture content at harvest of the hybrids varied from 16 to 24% at the first sowing time. Yields at the second sowing time were higher. The low yield of the PR34B97 hybrid coupled with a higher seed moisture content. In addition, the maximum value of the LAI was more favourable at the first sowing time, and ranged between 5-5.5 m2/m2.
    The crop year had a more dynamic effect on maize than the sowing time. First of all, the quantity and distribution of precipitation played an important role in respect to yield safety.

  • The effect of agrotechnological factors and the cropping season on sweetcorn (Zea Mays L. convar. saccharata Koern.) production in a humid year
    146-151
    Views:
    72

    We have examined the effect of three agrotechnological factors (sowing time, fertilization, crop density) and four genotypes on the yield
    of sweetcorn on chernozem soil in the Hajdúság region in 2009. The experiment was set up at the Látókép Research Site of the University of
    Debrecen. We have included two sowing times (27 April, 26 May), six nutrition levels (control, N30+PK, N60+PK, N90+PK, N120+PK,
    N150+PK) and four genotypes (Jumbo, Enterprise, Prelude, Box-R) at two crop density levels (45 thousand ha-1).
    In the humid cropyear of 2010 the amount of precipitation exceeded the 30-year average by 184 mm in the cropping season; the average
    temperature exceeded the same by 0.8 C on the average of the examined months. The circumstances were most favourable for sweetcorn
    production with the first sowing time, thus, this was when the yield of all hybrids was the highest.
    With early sowing time, the highest yield (23437 kg ha-1 yield) was obtained with Enterprise at 45 thousand ha-1 crop density level at
    N150 + PK nutrition level. The highest yield of the other three hybrids was 22253 kg ha-1 (Jumbo) 22286 kg ha-1 (Box-R) and 1873 kg ha-1
    (Prelude). With the second sowing time, the highest yield was obtained with Enterprise again (22237 kg ha-1) at 65 thousand ha-1 crop
    density level. With this sowing time the yield of Jumbo, Box-R and Prelude was 20888 kg ha-1, 17796 kg ha-1 and 17401 kg ha-1, respectively.
    We found that the highest yield was obtained at the highest nutrition levels (N120 + PK, N150 +PK) with the first sowing time, while the same
    was obtained at lower nutrition levels (N90 + PK, N120 + PK) with the second sowing time.

  • Technological development of sustainable maize production
    83-88
    Views:
    146

    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 eight ha field. The size of one plot was 206 m2, this it was a half-industrial experiment. 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. Yield increasing effect of the fertilizer also depended on the number of plants per hectare at a great extent. The number of plants of the six tested hybrids was 60, 70, and 80 thousand plants per ha.
    In Hajdúszoboszló, in 2016 the amount of rainfall from January to October was 605 mm, which was more than the average of 30 years by 160 mm. The yield of hybrids without fertilization changed between 9.63–11.6 t ha-1 depending on the number of plants.
    The six tested hybrids is 10.65 t ha-1 in the average of the stand density of 60, 70 and 80 thousand plants per hectare without fertilization, while it is 12.24 t ha-1 with N80+PK fertilizer treatment. That increase in the yield is 1.6 t ha-1, it is significant.
    Da Sonka hybrid is sensitive to weather, it is able to produce 6 t ha-1 additional yield in case of favourable condition. However, it has a low stress tolerance. The most stable yields were observed at Kamaria and Pioneer hybrids. The effect of vintage is also an important factor on the yield. In average, the yield of maize was 6.81 t ha-1 in 2015, which was a drought year and 11.86 t ha-1 in 2016 that was a favourable year.

  • Effect of cultivation factors on the yield and yield security of maize
    263-265
    Views:
    122

    Cultivation factors have a significant effect on the yield and yield security of maize. Ensuring a suitable green crop is important. Tricultural crop rotation (pea–wheat–maize) in the average of 25 years provided a 2 t ha-1 higher yield compared to monocultural cultivation. A harmonious NPK nutriment supply determines yield and yield security, which can be especially realized by means of the application of precision cultivation technologies. Under average circumstances N 80 kg ha-1, P2O5 50 kg ha-1, K20 60 kg ha-1 active ingredient is the agro-ecological dosage of artificial fertilizer.
    Plant density is a factor that determines yield. Optimal plant density – beside the genetic characteristics of the hybrid – is mostly influenced by the level of water and nutriment supply.

  • Examination of the impact of sowing technology models on the ear, constiuent and yield parameters of the yield formation elements of maize hybrids of different genotypes
    17-23
    Views:
    110

    Production year 2012 has been characterised by climatic extremities. The weather of this year can be considered very contradictory in terms of maize production. The droughty conditions of the winter and spring months had a negative effect on both germination and starting vigour. The favourable weather of May-July created ideal conditions for intensive growth and generative processes; however the lack of precipitation in August and September had a damaging effect on the development of yield composing elements and grain saturation processes as well. Under such circumstances, the sowing date models caused significant differences in the yield and quality of the hybrids belonging to different growth periods. The growing period of the maize hybrids has been shortened as a result of the unfavourable climatic conditions.

    Based on the trial results, it is verifiable that short growing period hybrids can be securely sown in draughty years even with a later sowing date, however using a later sowing date in the case of longer growth period hybrids may result even in a yield loss of 2–3 t ha-1. In the case of early and average sowing dates, with given yearly conditions the hybrids of the observed FAO 370-390 hybrid group provided the best result (12.40 t ha-1, 10.99 t ha-1), while in the case of the third, late sowing date the yield dominance of the FAO 290-350 hybrid group is the most significant (10.08 t ha-1).

    The analysis of the yield composing elements found that the P9578 hybrid has the highest shelling ratio, while its cob is the shortest. The P9494 hybrid has a high yield and the highest thousand grain weight, while the DKC 4983 has the longest cob and its thousand grain weight is above 300 g.

    The results confirm the fact that DKC 4590 has the highest yield potential and starch content, while in terms of oil and protein content the Szegedi 386 and NK Octet hybrids are the most important.

  • The Effect of Fertilization and Irrigation on Maize(Zea mays L.) Production
    26-29
    Views:
    111

    In 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.

  • Biostimulant induce growth, chlorophyll content and fresh herbage yield of alfalfa (Medicago sativa L.) and variegated alfalfa (Medicago × varia Martyn) plant
    19-25
    Views:
    31

    The use of biostimulants is associated with promoting plant growth by stimulating cell division and improving nutrient availability and uptake. A study was conducted at the University of Debrecen, Hungary, to examine the effect of biostimulants on alfalfa growth, chlorophyll content and fresh herbage yield. The experiment was arranged in a randomised complete block design with three biostimulant treatments plus control replicated three times. Data collected were subjected to analyses of variance using Genstat, where significantly different means were separated at a probability of 5% using the least significant difference. The findings show no different variation in plant height or chlorophyll content (SPAD) throughout the early stages of growth. Nonetheless, a notable impact was noted in the latter stages (28 days after biostimulant treatment application) on the growth of the alfalfa plant. Biostimulant treatments did not had effect on fresh yield for second through fourth cuts, but the fifth cut showed a significant effect, with T1 treatment recording the highest herbage yield of 19745 kg ha-1 followed by T2 (Tricho Immun plus Ino Green) and T3 (Tricho Immun), with yields of 19528 kg ha-1 and 17273 kg ha-1, respectively, while the T0 (control) recorded the lowest herbage yield of 12060 kg ha-1. However, the average mean yield indicated the application of biostimulants significantly increased fresh yield herbage by 20.5%. Correlation coefficient values suggested plant height at both 14 and 28 DAH (days after harvest) strongly correlated with fresh herbage yield (r = 0.7756 and 0.7455) which reflected in the increase in fresh herbage yield. Therefore, our results suggest that the use of biostimulants in alfalfa cultivation holds promise for improving growth and yield potential through their positive effects on chlorophyll content and the growth of alfalfa plant.

  • The Effect of Sowing Time and Plant Density on the Yield of MaizeHybrids
    95-104
    Views:
    72

    The crop technology of maize has two important elements, sowing time and plant density. In 2003 and 2004 we studied the effect of these two factors on the growth and production of maize in an experiment carried out near Hajdúböszörmény.
    The soil of the experimental plots was meadow soil.
    Weather in both years was differed greatly. 2003 was drought. Neither the distribution nor the quantity of the precipitation were suitable in the growing season for maize. This fact basically determined the results.
    In 2004, we could talk about a favorable and rainy season. The distribution and quantity of precipitation was suitable between April and September. The average temperature was also suitable for maize.
    Results of the sowing time experiment:
    In 2003, we tested seven hybrids at four sowing times. Hybrids in the early maturity group gave the highest yield at the later sowing time, while the hybrids of the long maturity group gave it at the earlier planting time. The yield of PR34B97, PR36N70, PR36M53 hybrids was the best at every planting time. The moisture loss of hybrids in the late maturity group was faster in the maturity season, but the seed moisture content was higher than the hybrids with early sowing time. The seed moisture content was very low due to the droughty year. In two hybrid cases, this value was higher than 20% only at the fourth sowing time.
    In 2004, we examined the yield and seed moisture content of nine hybrids. In the favorable crop year, the yield of every hybrid was the highest at the second and third sowing time. Yields of PR34H31 and PR38B85 hybrids were significant. The seed moisture content at harvest was higher than the previous year due to the rainy season. In the case of hybrids sown later, this value was higher by 30%. However, we noticed that this value was lower at the earlier sowing time than at the later.
    The crop year had a more dynamic effect on maize than the sowing time. First of all, the quantity and distribution of precipitation played an important role in respect to yield safety.
    Results of the plant density experiment:
    We tested the reaction of hybrids at four plant densities (45,000, 60,000, 75,000 and 90,000 stock/ha) every two years. In 2003, the tested seven hybrids reached the highest yield at the 90,000 stock/ha in the face of a droughty year. The effect of forecrop and favorable nutrients caused these results. In the rainy 2004 year, the yield grew linear with the growing plant density. The yield of the best hybrids were 14-15 t/ha at the 90,000 stock/ha.
    Such a high plant density (90,000 stock/ha) couldn’t adaptable in farm conditions in rainy season. It is practical to determine the interval of plant density besides the optimum plant density of hybrids which gave correct yield. The farmers have to use the low value of this interval due to the frequent of the droughty years.

  • Impact of weather on the spring crops yield in Croatia with emphasis on climatic change and the 2014 growing season
    41-46
    Views:
    157

    Main field crops in Croatia are maize, soybean, sunflower and sugar beet. By these crops are covered (status 2014) close to 50% (385 234 ha) of utilized arable land. Global warming, have often adverse influence on field crop yields. Aim of this study was testing precipitation and temperature regimes on spring crops yield in Croatia in 15-year period (1999–2013) and elaboration of the 2014 growing season with aspect of climatic change.

    Four growing seasons (2000, 2003, 2007 and 2012) were less favorable for maize because annual yield was bellow 5 t ha-1 (average 4.38 t ha-1), while in four more favorable years (2005, 2008, 2009 and 2010) annual yield was above 6.8 t ha-1 (average 7.32 t ha-1). Average precipitation and temperature for the April-September period in Osijek were 226 mm and 496 mm, 19.6 oC and 18.6 oC, for less and more favorable years, respectively. Yields of soybeans and sugar beet have mainly similar trend as maize yields in function of weather conditions, while sunflower is more susceptible to extremely moist growing seasons (for example, 2001 and 2005: 650 mm and 697 mm precipitation and very low yields in level 1.7 and 1.6 t ha-1, respectively). On the other side, under drought conditions of 2003, 2007 and 2012, yields of sunflower were above average in range from 2.5 to 2.7 t ha-1), while at same period yields of maize, soybean and sugar beet were drastically reduced.

    Average precipitation in the April-September period of 2014 for eight selected sites of Croatia was 756 mm or for 68% higher in comparison with the long-term average 1961–1990 with variation among the sites from 520 mm in Osijek to 910 mm in Varazdin. On the other side, average air-temperature in 2014 was 17.8 oC or for 0.7 oC higher with variations among the sites from 17.2 oC in Daruvar and Varazdin to 18.2 oC in Osijek and 18.3 oC in Gradiste. Under these favorable weather conditions, annual yields of maize (8.1 t ha-1), soybeans (2.8 t ha-1) , sunflower (2.9 t ha-1) and sugar beet 63.6 t ha-1) were considerable higher than usual.