The aim of this work was to evaluate the changes of different sulphur forms (soluble, adsorbed) in chernozem soil in a long-term field experiment supplied with increasing doses of NPK fertilizers for a long time. In addition, other objective of this study included the examination of the applicability of recommended extractants of the different...sulphate fraction in Hungarian soils. A long-term field experiment was established at the Research Station of Látókép of the University of Debrecen in 1984. In addition to control, two levels of NPK fertilizer doses have been used with irrigated and non-irrigated variants. Winter wheat and corn were cropped in a crop rotation on plots. Soil samples were collected in three different development stages of winter wheat, at the stage of stem elongation (April), flowering (May) and ripening (June of 2018) from the topsoil (0–20 cm) of experiment plots. Water-soluble inorganic sulphate was extracted with 0.01M CaCl2 solutions. The soluble plus adsorbed sulphate was extracted with 0.016M KH2PO4 solution. Sulphate was measured by turbidimetric method. 0.01M CaCl2-SO42— ranged between 0.293–1.896 mg kg-1 and the 0.016 M KH2PO4-SO42- varied between 5.087–10.261 mg kg-1. The values of KH2PO4 SO42- was higher than that of CaCl2-SO42-, because KH2PO4 extracted the adsorbed and soluble fractions of sulphate, while CaCl2 extracted the soluble sulphate fraction. The amount of absorbed sulphate was calculated by the differences of KH2PO4- SO4 and CaCl2-SO4. The KH2PO4 characterizes mainly the adsorbed sulphate fraction much more than the water-soluble fraction. KCl is the most widely used extractant for the determination of plant available sulphate content of soil in Hungary; therefore, KCl-SO42- fraction also was determined. The KCl-SO42- ranged between 0.328–2.152 mg kg-1. The CaCl2-SO42- and KCl-SO42- fractions were compared and based on Pearson's linear correlation, moderate correlation was established (r=0.511) between them. In all three extractant (0.01M CaCl2, 1M KCl, 0.016 M KH2PO4) higher sulphate fractions were measured in the fertilized plots where superphosphate had been supplied for ages until 2010. The arylsulphatase activity of soil also was determined and ranged between 9.284 and 26.860 µg p-nitrophenol g-1 h-1. The lowest value was observed in the treatment with highest NPK2 dose, both in irrigated and non-irrigated areas.
In precision nutrient management the most important aspect is adaptation but we should consider the possibility of the long-term improvement of soil fertility within the less fertile landscape zones. This possibility can be evaluated principally by long-term field experiments, which are running on similar soil types. The results of these...field experiments can indicate that which soil fertility status should be attained. Some more important soil fertility data, (such as pH, P-, K- and soil organic matter (SOM) content) of a long-term field experiment with increasing farmyard manure(FYM) doses or equivalent NPK fertilizers, set up on an Eutric cambisol, are presented. The yieldincreasing capacity of FYM doses was only 82%, as compared to the equivalent amount of mineral NPK, but long-term FYM treatments resulted in 10% higher SOM content than that of equivalent NPK
fertilizer doses. The studies indicate that SOM content is a function of local climate and clay content of the soil, and neither long-term high FYM doses can increase SOM content steadily above a supposed steady-state value. However we have to make efforts to keep the optimum level. The lowest soil reactions developed both with the highest NPK doses and without any fertilization. AL-P2O5 content of soil was increased more by mineral fertilization than by FYM treatments, but in case of AL-K2O content there was no difference between the fertilization variants. However the highest doses of both fertilization variants increased soil nutrient content to an excessive degree. Wecould get very valuable data from the unfertilized control plots as well, where long-term yield data suppose 48 kg ha-1 year-1 air-borne N-input.
Molybdenum, as a constituent of several important enzymes, is an essential microelement. It can be found in all kind of food naturally at low
levels. However, environmental pollution, from natural or anthropogenic sources, can lead to high levels of the metal in plants. Our study is based on long-term field experiments at Nagyhörcsök, wher
The crop rotation experiment, established by Vilmos Westsik in 1929, is the best known and most remarkable example of continuous production in Hungary. It is still used to study the effects of organic manure treatment, develop models and predict the likely effects of different cropping systems on soil properties and crop yields. Westsik’s cro...p rotation experiment provides data of immediate value to farmers concerning the applications of fertilisers, green, straw and farmyard manure. The experiment also provides a resource of yield, plant and soil data sets for scientific research into the soil and plant processes which control soil fertility, and into the sustainability of production without environmental deterioration. The maintenance of Westsik’s crop rotation experiment can be used to illustrate the value of long-term field experiments.
This work is about the molybdenum-accumulation of cereals analyzing soil and plant samples from a field experiment set in
Nagyhörcsök by Kádár et al. in 1991.
In this long-term field experiment different levels of soil contamination conditions are simulated. Soil and plant samples were collected
from the experiment station to study
In this report results of maize, winter wheat, winter barley and soil analysis are presented. The conclusions are as follows:
– Analysing soil samples from 1991 we have found that roughly half of the molybdenum dose applied is in the form of NH4-acetate+EDTA soluble
– Comparing element content of grain and leaf samples we have experienced that molybdenum accumulation is more considerable in the vegetative plant parts
– Winter wheat accumulated less molybdenum then maize in its vegetative parts. Comparing molybdenum content of winter wheat to winter barley we found that the concentration of the element in wheat was lower by half than in the winter barley. It seemed that molybdenum accumulated to the least degree in winter wheat.
Molybdenum as a constituent of several inmportant enzymes is an essential micorelement. It can be found in all kind of food naturally at low level, however, environmental pollution, from natural or anthropogenic sources, can lead to high level of the metal in plants. Our study is based on the long-term field experiments of Nagyhörcsök, where...different levels of soil contamination conditions are simulated. Plant samples were collected from the experiment station to study the behaviour of elements: uptake by and transport within the plants, accumulation in different organs, phytotoxicity and effects on the quantity and quality of the crop.
In this work we present the effect of molybdenum treatment on the uptake of other elements. Molybdenum is proved to be in an antagonist relationship with copper and sulphur, while molybdenum-phosphorus is a synergist interaction.
However, in most of the plants we studied increasing molybdenum-treatment enhanced cadmium-uptake. We have found the most significant cadmium-accumulation in the case of pea, spinach and red beet.
The aim of this paper was to provide further information about the nitrogen mineralization processes of soil. A modified incubation technique was applied to establish the amount of easily soluble mineral and organic N forms during the incubation period. An acidic sandy soil was used for incubation, which was sampled from the „Westsik” long-...term field experiment. The incubation was carried out on fifteen selected soil samples which were received different treatments since the experiment was set up.
From the obtained results, the amount of potentially mineralizable N and the mineralization rate constant were determined. Results of chemical analysis and biological interpretation of results are discussed.
The effect and interaction of crop production factors on maize yield has been examined for nearly 40 years at the Látókép Experiment Site of the University of Debrecen in a long-term field experiment that is unique and acknowledged in Europe. The research aim is to evaluate the effect of fertilisation, tillage, genotype, sowing, plant densit...y, crop protection and irrigation. The analysis of the database of the examined period makes it possible to evaluate maize yield, as well as the effect of crop production factors and crop year, as well as the interaction between these factors.
Based on the different tillage methods, it can be concluded that autumn ploughing provides the highest yield, but its effect significantly differed in irrigated and non-irrigated treatments. The periodical application of strip tillage is justified in areas with favourable soil conditions and free from compated layers (e.g. strip – strip – ploughing – loosening). Under conditions prone to drought, but especially in several consecutive years, a plant density of 70–80 thousand crops per hectare should be used in the case of favourable precipitation supply, but 60 thousand crops per hectare should not be exceeded in dry crop years. The yield increasing effect of fertilisation is significant both under non-irrigated and irrigated conditions, but it is much more moderate in the non-irrigated treatment.
Selecting the optimum sowing date is of key importance from the aspect of maize yield, especially in dry crop years. Irrigation is not enough in itself without intensive nutrient management, since it may lead to yield decrease.
The results of research, development and innovation, which are based on the performed long-term field experiment, contribute to the production technological methods which provide an opportunity to use sowing seeds, fertilisers and pesticides in a regionally tailored and differentiated way, adapted to the specific needs of the given plot, as well as to plan each operation and to implement precision maize production.
The impact of the climatic factors of crop year on the relative chlorophyll content of maize was examined for three years. The examinations were carried out on the Látókép Experiment Site of the University of Debrecen on calcareous chernozem soil in a small-plot, non-irrigated long-term field experiment with strip plot design. In addition to... a non-fertilised (control) treatment, nitrogen (N) fertiliser doses were applied as base and top dressing. The 60 and 120 kg N ha-1 base dressing doses were followed by two top dressing doses at the V6 and V12 phenophases.
Averaged over the different fertiliser treatments, SPAD readings increased in all three years as the growing season progressed. The highes SPAD value increase was observed in the average crop year (2017) at the V12 phenophase (11.8), which further increased at the R1 phenophas, by 3,7. No significant Spad value difference was observed between the average (2017) and the dry year (2018) at the V6 growth phase. However, in the wet crop year (2016), the V690 treatment provided the statistically highest relative chlorophyll content (46.8). At the V12 phenophase, the base dressing dose of 120 kg N ha-1+30 kg N ha-1 (V6150) showed to be successful in two years (2016 and 2018), while in 2017, the base dressing dose of A60 was successful. The impact of crop year on relative chlorophyll content can be clearly shown at the R1 growth stage. In all three years, the significantly highest relative chlorophyll content could be achieved at different nutrient levels: A60 in 2016, V6150 in 2017 and V690.
In a wet year (2016), higher yield could be achieved as a result of the 60 kg N ha-1 base dressing and 30 kg N ha-1 at the V6 growth stage (V690) as top dressing in comparison with 2017 and 2018, when higher fertiliser dose (120 kg N ha-1 base dressing and 30 kg N ha-1top dressing at the V6 growth stage) was needed to achieve a significant yield surplus.
Altogether, averaged over the different treatments, the highest yield (12.48 t ha-1) was observed in the wet year, when the relative chlorophyll content was also the highest (50.6).
Wheat production is significant branch of Hungarian crop production (with about 1 million hectares of sowing area). Weather anomalies resulted by climate change have increased the importance of biological basis in wheat production. Yield quality and quantity parameters of three wheat genotypes sown on chernozem soil type after maize pre-cro...p were studied in a long-term field experiment. Yield amount of the studied genotypes varied between 2894 and 8074 kg ha-1 in 2017 and between 5795 and 9547 kg ha-1 in 2018 depending on the applied treatments. Based on our results it can be stated that in both studied crop years the highest yield increment was realized by the application of the nutrient supply level of N30+PK. As the result of the application of the optimum mineral fertilizer level – in contrast to the control – resulted in significant yield increment in both crop years. The results of the long-term field experiment prove that water utilization of the studied wheat varieties / hybrids was improved by the application of the optimal nutrient supply. Furthermore, the water utilization of the latest genotypes was more favorable by both the control and the optimum nutrient supply level treatments. Analyzing the quality parameters of winter wheat using the NIR method it has been stated that the quality results of the well-known genotype (GK Öthalom) were better than those of the new genotypes. A negative correlation between winter wheat quality and quantity parameters has also been confirmed. As the result of the mineral fertilizer application protein and gluten content of winter wheat increased to a significant extent.
In this study the effect of N,P and K nutrients on the S and protein content of wheat grains was investigated in a long-term fertilization experiment set up in Nagyhörcsök. The calcareous chernozem soil having the following characteristics: pH (KCl): 7.3, CaCO3: 4.27%, humus: 3.45%, Al-soluble P2O5 and K2...O: 60–80 and 180–200, KCl- Mg: 150–180, KCl+EDTA-soluble Mn-, Cu- and Zn-content: 80–150, 2–3 and 1–2 mg kg-1. The experiment had a split-split-plot design with 40 treatments in 4 replications. Plant samples were collected from 2002 and 2004. 2002 was a drought year while 2004 was very wet.
The main conclusions are as follows:
– The sulphur and protein content were than the control higher in every NPK treatments.
– The sulphur and protein content of the wheat grains were higher in 2004 that had a lot of rain than in 2002 that had drouht.
Molybdenum is not a well-known microelement, but being a constituent of several important cellular enzymes it is an essential microelement. Molybdenum occurs in all foods, but at very low levels. There does not appear to be any particular foods or types of foods, which in the absence of extrinsic factors, naturally have high levels of molybdenu...m. However, environmental pollution, from natural or anthropogenic sources, can lead to high level of the metal in plants.
Our study is based on the long-term field experiments of Nagyhörcsök, where different levels of soil contamination conditions are simulated. Soil and plant samples were collected from the experiment station to study the behaviour of molybdenum: total concentration, available concentration, leaching, transformation, uptake by and transport within the plants, accumulation in different organs, phytotoxicity and effects on the quantity and quality of the crop. In this work we present the results of maize and peas and the soil samples related to them.
According to our data molybdenum is leaching from the topsoil at a medium rate and it appears in the deeper layers. In the case of plant samples we found that molybdenum level in the straw is many times higher than that is in the grain, so molybdenum accumulates in the vegetative organs of the plant. The data also show differences in the molybdenum-uptake of cereals and Fabaceae (or Leguminosae).
We have carried out our outdoor field experiments at the Látókép Experimental Farm of the CAS of the University of Debrecen in the cropyear of 2012/2013 on chernozem soil in a long-term experiment. We have studied the effects of two different preceding crops (sweet corn, sunflower) on the development of the SPAD values of wheat varieties of...different genotypes in the cases of control, N60+PK and N120+PK fertilizer treatments. According to our research results, we have concluded that the preceding crop, the fertilizer application and the variety selection influenced the SPAD values. According to our data, we have measured higher SPAD values after sweet corn preceding crop, the standard deviations were in a smaller range in the case of the studied varieties. After sunflower preceding crop, smaller averages were experienced with wider standard deviation range. In the case of favourable preceding crop, the differences between the varieties are more pronounced than in the case of unfavourable preceding crop. The maximal SPAD values were measured in milky ripening in the case of N120+PK fertilizer treatment.
...5); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">In this study the effect of N, P and K nutrients on the Cu and Fe content of winter wheat (Triticum aestivum L.) grains was investigated in a long-term fertilization experiment set up in Nagyhörcsök. Samples were also harvested from four experimental stations of the Hungarian national long-term fertilization trials. These are the following: Bicsérd, Iregszemcse, Karcag, and Putnok. Plant samples were collected in 2005 which was very wet. Our results from Nagyhörcsök were compared with the Cu and Fe content of samples which were harvested from control plots of other experimental stations. The Cu and Fe content of grain samples were measured using inductively coupled plasma mass spectrometer (ICP-MS) followed by digestion with HNO3-H2O2 solution. All data were subjected to ANOVA, and when significant differences (P<0.05) were detected, Duncan’s test was performed to allow separation of means.
Maize is a worldwide dominant plant. According to nowadays plant production principles it is important to investigate and optimize the site-specific nutrient-supply and other production factors, such as hybrid and irrigation, in the case of this plant as well.
At the Research Institute of the University of Debrecen, Center of Agricultural Sc
We have chosen three maize hybrids – that have been bread in Martonvásár – for our investigations. The effect of macronutrients is investigated in this experiment on five levels. The half of the experimental area can be irrigated during the vegetation period – whenever it is needed – by linear irrigation equipment, but on the other half only the water amount originating from the precipitation can be used by plants.
In the year 2008 the hybrid affected the grain moisture content at P=0.1% level, while nutrient-supply had an effect at P=10% significance level. We haven’t revealed either any effect of irrigation or of interrelationship between production factors. It can be stated that there are differences between the hybrids on each nutrient-supply and on both irrigation levels. The grain moisture content increased parallel to the longer vegetation
The starch content of maize is mostly affected by the hybrid,
so on P=0.1% significance level. Regarding our results, it can be
stated, that the starch content shows a decreasing tendency
parallel to the longer vegetation periods.
Our research work was carried out in the Westsik crop rotation field experiment in 2018. The main research purpose was to analyse the effect of the different organic and chemical fertilizers on parameters of rye. Our results revealed some differences between the different fertilization methods. One spike weight, grain weight of one spike, r...ye plant height, rye plant weight per m2 and 1000 seed weight in crop rotations VII, XV and VIII were different from the data of all crop rotations. This finding can be explained by the fact that crop rotations VII and XV were non-fertilized, only 23.3 t ha-1 straw manure (VII) or green lupine manure was applied as a second crop (XV). In addition, crop rotation VIII consists of four parts where we apply chemical fertilization with green lupine manure as a main and second crop. There is a positive close correlation between rye plant height and other studied characters (rye plant weight per m2, spike length, weight of one spike, grain weight per spike, spike weight per m2, grain weight per m2 and 1000 seed weight).
The effect of crop production factors on the grain yield was analysed on the basis of three-factorial experiments laid out in a split-split-plot design. In the case of maize the studies were made as part of a long-term experiment set up in 1980 on chernozem soil with forest residues, well supplied with N and very well with PK. The effects of fi...ve N levels in the main plots and four sowing dates in the subplots were compared in terms of the performance of four medium early hybrids (FAO 200). In the technological adaptation experiments carried out with durum wheat, the N supplies were moderate (2010) or good (2011), while the P and K supplies were good or very good in both years. Six N top-dressing treatments were applied in the main plots and five plant protection treatments in the subplots to test the responses of three varieties.
The results were evaluated using analysis of variance, while correlations between the variables were detected using regression analysis.
The effect of the tested factors on the grain yield was significant in the three-factorial maize experiment despite the annual fluctuations, reflected in extremely variable environmental means. During the given period the effect of N fertilisation surpassed that of the sowing date and the genotype. Regression analysis on the N responses for various sowing dates showed that maize sown in the middle 10 days of April gave the highest yield, but the N rates required to achieve maximum values declined as sowing was delayed.
In the very wet year, the yield of durum wheat was influenced to the greatest extent by the plant protection treatments, while N supplies and the choice of variety were of approximately the same importance. In the favourable year the yielding ability was determined by topdressing and the importance of plant protection dropped to half, while no significant difference could be detected between the tested varieties. According to the results of regression analysis, the positive effect of plant protection could not be substituted by an increase in the N rate in either year. The achievement of higher yields was only possible by a joint intensification of plant protection and N fertilisation. Nevertheless, the use of more efficient chemicals led to a slightly, though not significantly, higher yield, with a lower N requirement.
Our field researches took place on the Látókép test farm of Agricultural Science Centre of University of Debrecen, Centre for Agricultural and Applied Economic Sciences, in long-term experiment, on calcareous chernozem soil, in growing season of 2014/2015. In our experiment we examined the fertilizer reaction and the yield of different winte...r wheat genotypes (GK Öthalom, GK Csillag, Mv Csárdás, Mv Toldi) with grain maize and sweetcorn forecrops. According to our results, the sweetcorn forecrop strongly affected the yield. In the average of the fertilizer treatments and the varieties, after sweetcorn forecrop 6.9 t ha-1, after grain maize forecrop 5.4 t ha-1 average yield was gained. According to our data, the fertilizer reactions of the varieties were significantly different.
Wheat production is a determining branch within Hungarian crop production (produced on nearly one million hectares). Weather anomalies caused by climatic change confirmed the importance of the biological background (variety, hybrid) in wheat production. The adapting ability and reaction of different wheat genotypes towards nutrient supply were...studied in a long-term field experiment on chernozem soil type in the case of different pre-crops (sunflower and maize). According to the experimental results of the vegetation of 2017/2018, the yield of the variety Ingenio sown after the sunflower as previous crop ranged between 4168 and 8734 kg ha-1, while in the case of maize as previous crop, this value ranged between 2084 and 7782kg ha-1, depending on the applied nutrient supply level. The studied genotypes produced rather significant yield surplus as a response to the application of mineral fertilization (4.6–5.1 t ha-1 after sunflower and 5.7–6.3 t ha-1 after maize). Optimal mineral fertilizer dosage was determined by both the genotype and the pre-crop. N-optimum values of wheat genotypes was determined using regression analysis. In the case of the variety Ingenio sown after sunflower, the optimum range was N144-150+PK, while after maize, it was
N123-150+PK, respectively. For the hybrid Hyland, these optimum ranges were N114-120+PK, just as N150-153+PK, resp. The application of optimal mineral fertilizer dosages improved water utilization of the studied wheat genotypes to a significant extent. WUE values of the control, unfertilized treatments ranged between 4.1–8.3 kg mm-1, while in optimal fertilizer treatment, it ranged between 15.5 and 17.4 kg mm-1.
This paper presents economical importance of white lupin /Lupinus albus/. It is an important task as exceptional effectual green manure, that shows VIII treatment’s results of Westsik long-term field experiment. Content of white lupin seed is similar than content of soybean. By the forrage examination the soybean can substitute whit white lup...in seed in 40%. The main problem of the production of lupin seed is the want of long term herbicides. For the solve of this problem to find herbicides which are efficiant for 80-100 days. First we have try 26 different herbicides.
...5); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">We have conducted our research at the Látókép Research Farm of the University of Debrecen RISF Centre for Agricultural and Applied Economic Sciences during the cropyears of 2007, 2008 and 2009, on chernozem soil. In the case of crop rotation three models were set (mono-,bi- [wheat, maize] and triculture [pea, wheat, maize]). The five nutrient levels applied during the treatments were as follows: control [untreated], N60P45K45, N120P90K90, N180P135K135, N240P180K180. The conclusion of our results was the following: the crop rotation, the nutrient supply and the amount of precipitation all influenced the quantity of maize yield. As an effect of the increasing nutrient doses yield increase was experienced compared with the control treatments. In the average of the years the highest increase in yield excess/1 kg of NPK fertilizer was measured in the case of the monoculture (13 kg ha-1). As a consequence of is soil extorting effect the monoculture responded more intensively to the nutrient supplementation than the biculture or the triculture in the studied cropyears. In addition, we have observed that the three-year average yield amount per 1 mm precipitation was significantly influenced by the nutrient reserve of the soil. In the monoculture during the control treatment this value was 25 kg mm-1, the value measured in the case of the biculture turned out to be more favourable (42 kg mm-1).
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.
In the growing season of 2019, we analysed stress resulting from climatic factors on maize hybrids of different genotypes, with the aim of gaining a better understanding of the physiological responses of each hybrid, which might support the elaboration of a cost-effective irrigation plan.
Our experiments were carried out at... the Látókép Experimental Station of the University of Debrecen on calcareous chernozem soil in a small-plot long-term field trial with strip plot design. In the scope of the experiment, N-fertilizer doses were applied as basic fertilizer and top-dressing in addition to the non-fertilized (control) treatment. The 60 and 120 kg N/ha doses applied as basic fertilizers in the spring were followed by top-dressing in the V6 phenophase with a +30 kg N/ha dose. Measurements were carried out with the involvement of the Renfor early (FAO 320) and Fornad (FAO 420) late maturity hybrids-
The stomata of the plants became more and more closed with the progression of the phenological phases; their stomatal conductance decreased. However, the hybrids responded differently to environmental stress. In the case of the Renfor hybrid, the highest conductance (669 mmol/m2-s) was recorded in the V12 phenophase with the 150 kg N/ha treatment. The stomata were more open due to the high turgor pressure, allowing plants to evaporate properly. The plant was in its worst physiological condition on 2nd July, at the time of the appearance of the last leaf in the case of the 120 kg N dose (224 mmol/m2-s). The value measured in the V12 phenophase has already shown that the stomata were closing due to the self-regulating system of the plant. It would have been necessary to dispense irrigation water following the measurement. This confirms the finding that water stress can be prevented by measuring stomatal conductance.
In the case of the Fornad hybrid, stomatal conductance was the highest on 12th June (630 mmol/m2-s) in the 90 kg N/ha treatment and it was the lowest (183 mmol/m2-s) in VT (emergence of the last leaf) phenophase in the 60 kg N/ha treatment. In this case, the appropriate time for applying irrigation water would have been early July, when the conditions for the plants were still adequate. Subsequently, the stomata began to close due to a reduction of the water resources available to them.
There was a significant correlation between soil moisture and stomatal conductance, as well as between temperature and stomatal conductance.
The development of chernozem soil water management and its relationship with maize yields was studied in a 30-years long-term field experiment with different crop-rotation systems (mono-, bi- and triculture), in three crop years with different natural precipitation: a drought (2007), a wet (2008) and a dry (2009 one. The relevant soil layer was... divided to three sub-layers: (0–60 cm, 61–120 cm, 121–200 cm) in which the development of soil moisture content was investigated during the whole vegetation. From the results it can be stated that change of the water stock of the upper soil layer (0–60 cm) was the most intensive. Both the direct effect of natural precipitation and irrigation could be observed in the most obvious way in it. Yield result of maize and the highest water supply deficit values in the vegetation were compared in our work too. According to the results it was revealed that among the three studied crop rotation systems it was the monoculture, the success of production of which depends the most of water supply. The most favourable crop rotation system was the triculture from both the aspect of the yield of produced crops and the favourable soil properties too.