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5-8
No 552014

This study presents a PHP-based model capable of calculating maize leaf area index. The model calculates LAI from emergence to 75% silking. The basis of calculation is represented by the daily average temperature values. The usability of the model was tested using three years' temperature and LAI data series from the values obtained by the weat...her station set up at the Látókép Experiment Site of the University of Debrecen, Centre for Agricultural Sciences between 1994 and 1996. During the running of the model, it was observed that temperature affects the intensity of leaf development to a various extent.

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31
45
43-47
No 652015

Sow milk production is the major factor limiting pig growth to weaning. Although the milk production of the sows incremental many environmental factors affect the actual performances. The supplemental milk replacer can be an appropriate solution to ward off disparities and try to equalize the available milk quantity to the piglets according to ...their appetite, to enlarge the weight of pigs at weaning, ultimately. The aim of the present study was to investigate the effects of liquid milk supplement on weight development and litter performance of the piglets during the suckling period. Data were collected from 60 farrowings, the weight of 649 piglets in a total were measured at birth, 14 days old and at weaning (28 days), respectively. In the control group (n=319) the piglets were suckled and got prestarter feed from day 10. In the experimental group (n= 330) the piglets had got liquid milk replacer in 10.71% solution, from day 10 after birth together with suckling and prestarter feed, as well. Based on the Duncan's multiple range tests, there were no significant differences in birth weight between the control and experimental group but we found significant differences between the 14 days weight and the weaning weight, subsequently. Based on the CV% of weight the experimental group became more homogenous, in contrary to the weight of the control group at the end of suckling period. The milk supplementation can be an appropriate solution to ward off disparities and to equalize the available milk quantity to the piglets according to their appetite, to enlarge and uniform the weight of pigs at weaning, ultimately.

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32
49
87-90
No 692016

Piglets in commercial intensive pig husbandry are often abruptly weaned between 3 and 4 weeks for economic reasons. The process of weaning is a multifactorial stressor, in which nutritional, social, physical and psychologic stressors are combined. Piglets are often exposed to unfamiliar piglets around weaning which results in a period of vigoro...us fighting. Stress plays an important part in welfare research. Traditionally glucocorticoids are measured in blood samples but their use is often limited as the act of sample collection may stress an animal. Measurement of faecal cortisol/corticosterone metabolites is a non-invasive method for evaluation adrenocortical activity. The aim of this study was to examine the effect of litter’s let-together system (“kindergarten”) in the farrowing house by measuring faecal cortisol metabolites. According to our results the “kindergarten” system has no stress effect on sows and piglets, respectively.

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31
49
42-45
No 122003

The cultivation technology for those plant, that play a key role in arable land production need to be renewed in order to reduce production costs and to protect arable land. The modernisation of technologies can only be achieved by applying appropriate tillage systems. Our measurements were carried out on chernozem soil with lime deposits at th...e Látókép Experimental Station of the Center for Agricultural Sciences, Debrecen University, in long term tillage experiments set up in 1989. We examined the typical physical parameters, the albedo, field capacity, the bulk density of the soil, organic carbon content (humus %) and the measured pH-values in the water solution within the two tillage variations. We have also modelled nitrogen cycle formation in different treatments.
A significant difference occured between the albedos of the two soils, which may be the result of significant amounts of stem remaining on the surface in the case of the reduced tillage method. The yellow, waxy stem of maize reflects 21% of the sun’s rays, especially at the beginning of the vegetation period, when its decomposition has only just started. This delys the warming up in early spring, which delays the sowing time of maize and reduces evaporation. In the two tillage variations, the water management characteristics do not differ practically, the wilting point field capacity are in accordance. In reduced tillage methods, the so-called „plough-pan” can be well measured at 15-20 cm, while in winter ploughing it is at 30 cm. The humus % of the soil does not differ in the two tillage variations, but due to the difference in bulk density this means a different humus and organic nitrogen content. The organic nitrogen content is greater in the reduced tillage method. On the basis of pH value evaluations, we could not detect significant differences in the two tillage variations. The organic nitrogen content of areas where reduced tillage method was applied is higher than in areas where conventional winter ploughing was applied.

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7
11
55-60
No 22001

During our work, we developed a new, simple method to show the effects of fertilization on yield, which can both be applied over the long term as well as in series of independent experiments.
During the testing of this method, at the experimental farm of the Debrecen University Center for Agricultural Sciences at Látókép on a chernozem so...il with lime deposits, we examined the fertilizer reaction of maize hybrids between 1989 and 1994. The treatments were: winter tillage, plant density of 70-80 thousand, unfertilized, N 120, N 240 kg/ha fertilized treatments, long term experiments using Dekalb 524 and Volga SC hybrids in long term experiments.
Four parameters are shown in the model. In the examined period TRmax represents the greatest yield in the fertilized treatments, NT the yield in unfertilized treatment, k the „efficiency of fertilizer” to NT and b the depression-coefficient, where the expected value is zero. The expected grain yield of the fertilized treatments (Y), in the function of the unfertilized grain yield (x) is the following:

The parameters were determined using the Monte Carlo method, in the optimizing process the sum of deviation square was minimized. The correct conformation of the functions was determined by the greatness of the R-value and the standard error. We found that during six years of testing, the tendency of fertilization efficiency was similar in the case of both hybrids. There was an unfavorable weather interval and, in these years, the yields were low, fertilization did not have an effect and moreover, in extremely bad conditions resulted in an obvious yield decrease. With the  improvement of conditions, which in the case of our country means an increase in precipitation, the efficiency of fertilization increases and reaches its peak at 13-14 t/ha. At this point, the yield increasing effect of fertilization is 4-4,5 t/ha. If the yield of the unfertilized treatments increases from 8-9 t/ha, then the efficiency of the applied fertilizer decreases.
Most likely, the k and b parameters depend on the soil of the experimental location (nutrient and water management) and on the amount of  pplied fertilizer and the characteristics of the  hybrid. With the increase of fertilizer dosage the k-parameter also increases. The greater value though does not obviously mean a more favorable situation. It is true that in medium and good years this means great fertilizer efficiency, but in low or extreme precipitation conditions it also means greater risk. With the increase of the k-parameter, the yield deviation also increases which, from a cultivation point of view, is quite unfavorable. If the value of the b-parameter is other than, zero then the effect is clearly unfavorable, because with the increase of this value, the yield decrease is also greater. The fertilizer reaction of the two examined hybrids can be well characterized by these two hybrids.
Examining the six years, our created model estimated the effect of fertilization on the yield accurately and with a high degree of safety. Both in highly unfavorable and extremely good years, it gave an exact estimate. In our opinion, it can be used well to evaluate the effects of fertilization on yield in the future.

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7
64-69
No 262007

There is a mutual dependence between nature conservation activity and agriculture in Hungary, as the management of the protected areas cannot be achieved without ecological farming methods. Moreover, viable economic activity can be only imagined through the harmonization of agricultural and nature conservation interests. From a nature conservat...ion point of view, grass management systems play the greatest role in domestic agricultural systems. Yet, due to the prohibition of certain management methods and the spatial and temporal restraints on grazing, nature conservation activities have priority on protected grasslands. While nature conservation activity is still of prominent importance, it is not equally suitable for the economical management of protected grasslands per se. With our examinations, we would like to emphasize the common interests of these mutually dependent activities and to promote bilateral cooperation. Our aim is to model the production of grass on the great pastureland of Hajdúbagos. Potential grass production levels are easily calculable with a computer model based on data collected through a series of test harvests, as well as by factoring in changing climatic factors and by simulating the effects of grazing animal species and stocks. This model is not only useful for determining the optimal number of the grazing animal stock and grazing method, and therefore the most suitable management strategy, but it also supports local farmers to be able to plan their activities. In this way, both nature conservation and economic aims can be easily harmonized, which would be an important factor for the sustainable development of rural areas.

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7
10
40-46
No 112003

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 ir...rigated 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.

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10
20
26-29
No 112003

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 a...nd 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.

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