Maize (Zea mays L.) is the most important consuming cereal crop in the world after rice and wheat. This requires an understanding of various management practices as well as conditions that affect maize crop performance. Water deficit stress during crop production is one of the most serious threats to crop production in most parts of the world a...nd drought stress or water deficit is an inevitable and recurring feature of global agriculture and it is against this background that field study of crops response to water deficit is very important to crop producer and researchers to maximize yield and improve crop production in this era of unpredicted climatic changes the world over.
A pot experiment was carried out to determine the effects of water deficit on growth and yield formation of maize. Two maize cultivars were used Xundan20 and Zhongdan5485. Three levels of soil water content were used in two stages of water control levels at two stages of the maize plant development
1. The JOINTING STAGE: A. CONTROL (CK) soil water content: from 70% to 80% of soil water holding capacity at the field, soil water content: from 55% to 65% of soil water holding capacity at the field, soil water content: from 40% to 50% of the Soil water holding capacity at the field.
2. The BIG FLARE PERIOD: A. CONTROL (CK) soil water content: from 75% to 85% of soil water holding capacity at the field, soil water content: from 58% to 68% of soil water holding capacity at the field, soil water content: from 45% to 55% of the soil water holding capacity at the field.
This research mainly studied the effects of water deficit on physiological, morphology and the agronomical characteristics of the maize plant at the different water stress levels.
The importance of these results in this experiment will enable plant producers to focus and have a fair idea as to which stage of the maize plant’s development that much attention must be given to in terms of water supply.
...5); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">Plain and the influence of the hybrid, plant density, crop rotation, nutrient supply, weeds and irrigation on water use efficiency were studied.
...5); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">The paper is based on the researches carried out in the long term trial placed on the preluvosoil from Agricultural Research and Development Station Oradea, Crisurilor Plain in during 1976–2012.
Besides its effect on potato yield, water also has a significant impact on yield quality. Excess water (too much precipitation, over-irrigation) and the lack of water (lack of precipitation or irrigation) both trigger stress in the plant and can significantly worsen the quality of the yield (seed potato) and deteriorate the health of the plant...and the seed potato. Excess precipitaton or irrigation water leaches nitrate-nitrogen under the rhizosphere, consequently, the amount of available nitrogen decreases leading to the deficiency of N in potato. If water cover (the maximally saturated state of soil) exceeds 8-12 hours, it can cause root destruction (because of the lack of oxygen), which leads to the wilting and later to the death of the plant. Abundance of water caused by excess precipitation or irrigation is a major problem primarily on sandy loam, loam and clay loam soils with bad structure and water management qualities, but also on any soils, which are over-irrigated or irrigated at an improper time. Symptoms of the lack of water are detectable mostly when the available water content of the soil (disponible water) decreases under 60-65%.
In the present year, there was a lack of precipitation on the Great Plain, which can be compensated by proper irrigation. Unfortunately, this problem is further intensified by the high temperature, which results in faster ripening and accompanied with fluctuating soil moisture content, in the formation of secondary tubers.
Transcarpathia is located in one of the wettest parts of the Ukraine. There are 9429 rivers and creeks in the county with a total length of 19.86 thousand kilometers. The length of 152 rivers exceeds 10 km, 4 exceed 100 km (Tisza, Latorca, Ung and Borsava rivers). The average density of rivers is 1.7 km/km2, which is the highest in the Ukraine.... The existing water resources are distributed unevenly in the county. The river with the greatest mass of water is the Tisza. Tisza carries 75% of all existing water resources, the remaining 25% is made up of the water in the river Ung and Latorca. Disregarding the uneven distribution of water resources, 80% of water is used up in the basins of the rivers Ung and Latorca from the water resources of the county, which leads to the overload of rivers.
The main sources of water supply in Transcarpathia: subsurface waters – for the population of cities and settlements, surface and subsurface waters – for the industry, surface waters – for irrigation.
In the interest of protecting existing water resources, it is required to follow current regulations, detecting and averting contaminating sources and establishing water conservation zones.
The area and volume of processing tomato production is increasing in Hungary. Irrigation is crucial for processing tomato growing. To save water and energy, it is important to know exactly how much water is needed to reach the desirable quality and quantity. AquaCrop is a complex software, developed by FAO, which is able to calculate irrigation... water needs, several stress factors and to predict yields. A field experiment was conducted in Szarvas in processing tomato stands, under different irrigation treatments. These were the following: fully irrigated plot with 100% of evapotranspiration (ET) (calculated by AquaCrop), deficit irrigated plot with 50% of ET (D) and control (K) plot with basic water supply was also examined. Dry yield, crop water stress index and soil moisture were compared to modelled data. The yields in the plots with different access to water were not outstanding in the experiment. The model overestimated the yields in every case, but the actual and modelled yields showed good correlation. AquaCrop detected stomatal closure percentages only in the unirrigated plot. These values were compared to CWSI – computed from leaf surface temperature data, collected by a thermal cam in July – and showed moderately strong correlation. This result suggests that Aquacrop simulates water stress not precisely and it is only applicable in the case of water scarcity. Soil moisture data of the three plots were only compared by means. The measured and modeled data did not differ in the case of K and ET plots, but difference appeared in the D plot. The obtained results suggest that the use of AquaCrop for monitoring soil moisture and water stress has its limits when we apply the examined variables. In the case of dry yield prediction overestimation needs to be considered.
In this study, the effect of water supply on the quality and productivity of different maize hybrids was observed.
Maize production is influenced by many agro-technical factors such as nutrient supply, plant density, environmental factors, water supply and temperature. Good soil quality and adequate technology significantly... reduce the unfavourable effect of crop year. The impact of fertilization, crop rotation, irrigation and plant density on maize yield was greatly affected by crop year and crop rotation. The main constituent (69–75% dry matter concentration) of maize seed is starch, however, its increase can be achieved only to a limited extent, as increasing the starch content will reduce other parameters, especially protein content. Significant nutrient content improvements can be achieved by appropriate hybrid-site connection and the use of adequate technology. Protein content reduction with optimal water supply can be positively influenced by the appropriate nutrient supply for the hybrid.
The experiments were carried out at the Látókép Experimental Site of Crop Production on calcareous chernozem soil. The weather of the examined year, which was partly favorable for maize and partly unfavourable in other respects, was also reflected in the development of maize and yields achieved.
In 2019, we were examining the hybrids of Kamaria (FAO 370), P 9903 (FAO 390), DKC 4351 (FAO 370) and KWS Kamparis (FAO 350–400). Due to the dry soil condition, sowing was delayed, however, the hybrids emerged ideally because rain arrived soon after sowing, which facilitated initial development. Young plants evolved rapidly and dynamically in the case of all hybrids. In terms of heat-demanding bread, the month of May was unfavourable to temperatures below the annual average, but the higher amount rainfall helped the development. However, due to the drier period in early July, 25–25 mm of irrigation water was applied to half of the experimental areas on July 1 and 15.
The aim of our research was to determine the best population density for hybrids under favourable soil conditions (calcareous chernozem soil). In both irrigated and dry conditions, a crop density of 75,000 crops were the most favourable for the Kamaria hybrid. The P9903 hybrid in the case of a crop density of 85 crops proved to be ideal and the DKC4351 had an optimal population density of 95,000.
However, it should be taken into consideration that, in the case of soils with poor water management, the drought sensitivity of the crop stand may increase at a population density of 95,000.
As a result of irrigation, yield increased and the difference between the examined plant numbers decreased. The yield growth was relatively moderate (341 kg ha-1 – 1053 kg ha-1), which makes the economicalness of irrigation doubtful in the given year.
...5); font-variant-ligatures: normal; font-variant-caps: normal; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">The public water supply played a major role in the urbanization of Debrecen city, just like in the case of many other cities. We had plenty of water and so we wasted it. However nowadays we experience a considerable decrease in the level of groundwater which causes an increasing need of energy for pumping. Beside the above mentioned the ecological threat and the decreasing water quality are also major problems. This study attempts to draw attention to the possibilities and the future of the regional water supply, by showing the history of the water supply, the sanitation systems of Debrecen and their present day activities.
The decrease in Earth's drinking water resources and the degradation of its quality has become a critical problem. Our planet's total water supply is estimated to be around 2 billion km3s. This is only 1% of Earth's own weight. Of this small amount only a tiny 3% is fresh water, of which 79% is forzen in glaciers and 1% is present as surface wa...ters.The ratio of water stored in soil is around 20%. This is 0.2% of the total water supply. Our study aims to summarize the layered groundwater aquifer systems and its changes which are the results of anthropogenic effects in both global and hungarian respects and also for the region of Debrecen.In particular with regard to the geological and ecological level where irreversible
processes take place. All this is discussed in the context of cause and effect. Pointing out the dangers of excessive deep groundwater extraction and the contamination caused by toxic substances that are the byproducts of modern life. In addition we discuss the Water Directive of the European Union which gives a policy for community action concerning the goal to achive the status of „in good condition” for our waters till 2015.
Hungary is one of the countries in Europe which has the largest amount of water supply because of its geographical conditions. Water comes from the surrounding mountains makes this water supply even more bigger. This precious water base needs to be treated responsibly and the most efficient way. The Civaqua program is a project with the above-m...entioned conditions, made by the Local Government of Debrecen and the Water Directory of Trans-Tiszanian Region. This project deals with the exploitation of the East-Main Chanel’s water for social welfare, agricultural and inverimental protection purposes in Debrecen and its agglomeration. The aim of this paper is to give an overall insight into the investment plans of Civaqua program and it is also examines its positive direct and indirect effects on the region.
We have been studied the effects of crop-rotation, fertilization and irrigation on the yields of maize in different cropyears characterized
by different water supply (2007 year=dry; 2008 year=optimum) on chernozem soil. Our scientific results proved that in water stress
cropyear (2007) the maximum yields of maize were 4316 kg ha-1...up> (monoculture), 7706 kg ha-1 (biculture), 7998 kg ha-1 (triculture) in non
irrigated circumstances and 8586 kg ha-1, 10 970 kg ha-1, 10 679 kg ha-1 in irrigated treatment, respectively. In dry cropyear (2007) the
yield-surpluses of irrigation were 4270 kg ha-1 (mono), 3264 kg ha-1 (bi), 2681 kg ha-1 (tri), respectively. In optimum water supply cropyear
(2008) the maximum yields of maize were 13 729-13 787 (mono), 14 137-14 152 kg ha-1 (bi), 13 987-14 180 kg ha-1 (tri) so there was no
crop-rotation effect. In water stress cropyear (2007) fertilization caused yield depression in non irrigated treatment (control=2685 kg ha-1;
N240+PK=2487 kg ha-1). Our scientific results proved that the effects of abiotic stress could be strongly reduced by using the optimum crop
models in maize production. We obtained 8,6-11,0 t ha-1 maximum yields of maize in water stress cropyear and 13,7-14,2 t ha-1 in optimum
cropyear on chernozem soil with using appropriate agrotechnical elements.
During the industrial production of broiler chicken, a large amount of manure is produced, of which easily contained nitrogen content (without pre-treatment) is released into the atmosphere as an air pollutant. In our experiments, we aimed to prepare compost tea, also known as water extract of compost, from pre-treated poultry manure in order t...o create a product can be utilized as liquid nutrient supply. The poultry manure source was the Baromfi-Coop Ltd. located in Nyírjákó, Hungary, where it was treated by composting. As a result of this pre-treatment of the poultry manure, its nutrient parameters improve and nitrogen is present in a form that is better utilized for plants. Furthermore, this product is suitable for further utilization and also can be the base material for a brand-new product. For this reason the effects of compost/water ratio, incubation time, low oxygen level, and extraction time on the parameters of the resulted product were studied in the frame of developing new soil-life enhancing microbial product, so-called compost tea.
Chemical parameters of the compost used as base material strongly determined the properties of the resulted compost tea, especially the ratio of the various nitrogen forms, their concentration and the salt content. It was found that adding water at a higher rate that means 1/40 and 1/50 mixing ratios results in more cost-effective production. In the experiment the compost tea were held under oxygen-poor conditions, therefore pH of the extractions decreased, which influenced the quality and quantity of their nutrient content.
The effect of increasing fertilizer dosages on the yield of eight different maize hybrids (SY Ondina, NK Kansas, NK Lucius, NK Octet, NK Thermo, SY Flovita, SY Brillio, NX 47279) has been investigated in the crop-year of 2011. According to our results it can be stated that contrarily to the control treatment the application of different nutrien...t-levels has resulted a significant yield increment (2 000–5 800 kg ha-1).
Based upon the results of this experiment we have drawn the conclusion that the nutrient level of 120 kg N+PK was the optimal for the investigated hybrids. The highest yield (14 475 kg ha-1–15 963 kg ha-1) of the hybrids with different genotypes has been produced in case of this fertilizer treatment. With the comparison of the control and the optimum-fertilizer treatments the yield-increasing effect of mineral fertilization and the different reaction of hybrids towards increasing fertilizer dosages have been proven. In case of the control treatments the best-yielding hybrids were NK Thermo (11 917 kg ha-1) and NX 47279 (11 617 kg ha-1). Contrarily on the optimal nutrient supply level the hybrids SY Brillio (15 876 kg ha-1) and NX 47279 (15 963 kg ha-1) have produced the highest yields. Summarizing, we can state that the hybrid NX 47279 has resulted stable and high yields in the fertilized treatments. Analysing the yield-increasing effect of 1 kg fertilizer active substance it was proven, that the hybrids SY Flovita (45.43 kg ha-1), SY Brillio (44.47 kg ha-1) and NX 47279 (42.33 kg ha-1) had a good reaction towards even lower nutrient supply levels as well. In case of the control treatment the average water utilization coefficient of the hybrids was significantly lower (35.2 kg mm-1), than in case of the optimal nutrient supply level (N120+PK) treatments (48.9 kg mm-1).
Therefore the hybrid specific difference between the water utilization of genotypes could be revealed.
The effect of irrigation on tomato yield depends on the actual weather conditions, basically the air temperature and precipitation (quantity and dispersion). The irrigated plants gave a significantly higher yield, and rainfed plants showed a yield loss. The optimum water supply treatment gave a significantly higher proportion of lycopene than t...he control (rainfed) treatment (89% and 80% respectively) in case of Brixsol F1 variety. In spite of this we have not found significant difference in case of Strombolino F1 (cherry type). Content of total poly-phenols measured in Strombolino F1 (cherry type) was significantly higher than that found in the Brixol F1 (normal type). The optimum water supply treatment resulted in a significantly lower content of total polyphenols in both years. Tomato fruits are rich in polyphenols the largest amount of which is rutin from among the identified components.
Water deficiency has become one of the most limiting factors of crop production in Hungary as the tendency in annual amounts of precipitation shows a decreasing tendency; therefore, it has become similar to those of Southern Europe. The most significant decrease in precipitation occurs typically during spring, approximately 20% of the data expr...essed in the averages of the last century. Studying the relationship between water deficiency as a stress factor and nutrient supply is important in order to improve the production efficiency of crops. Nowadays, this problem receives outstanding attention presented in numerous papers both in Hungary and globally, however, there are several questions yet to be answered. Our pot experiments were carried out under controlled greenhouse conditions in order to establish new data on these relationships. Experimental soils were typical for Western Transdanubia, taken from long-term field experiments representing four different site characteristics of the region. It was concluded from the results that drought periods during the early growth stages (i.e. 4–5 weeks after emergence) of plants may result in significant decreases in both dry matter production, nutrient concentrations, nutrient uptake and shoot:root ratios. Better nutrient supply, especially potassium, plays a significant role in reducing the negative effects of water deficiency.
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.
Besides agro-techniques the climatic conditions play an important role in agricultural production. Weather extremes are
significant hazards to many horticultural regions all over the word. It has a profound influence on the growth, development and yields of a
crop, incidence of pests and diseases, water needs and fertilizer requirements i
stresses. Nowadays, the weather extremes cause more and more problems and significant hazards to many horticultural regions in Hungary.
The aim of this study is to explore the problems of nutrient uptake followed from climatic anomalies and response it. In this study
we focus on water supply problems (water-stress).
Reviewing the effects and nutrient disorders caused by climatic anomalies, the following statements can be taken:
· Nutrient demand of trees can be supplied only under even worse conditions.
· The most effective weapon against damage of climatic anomalies is preventative action.
· Proper choice of cultivars, species and cultivation should provide further possibilities to avoid and moderate the effects of
· Fruit growing technologies especially nutrition should be corrected and adjusted to the climatic events as modifier factors.
· The role of foliar spraying, mulching and fertigation/irrigation is increasing continuously.
· Urgent task of the near future is to correct and adjust the tested technologies of fruit growing according to these climatic events as
Optimal nutrient supply of trees decreases the sensitivity for unexpected climatic events. To solve these problems supplementary, foliar
fertilization is recommended, which adjusted to phonological phases of trees. Moreover, mulching is regarded as an excellent water saving
Mineral water consumption increased dramatically in the last 30 years. One reason for this change lies in the changing consumer behaviour: consumers are increasingly recognizing the importance of healthy nutrition and appreciate the beneficial nutritional physiological properties of mineral water. Local mineral water harmonizes well with import...ed waters. Bottled mineral water may travel several hundred kilometres until it reaches consumers. In the present study, the dynamic mechanical vibration caused by transporting on public roads was simulated in laboratory vibration tests then samples were subjected to microbiological examinations in compliance with legislations currently in force. Due to this vibration, the initial microbe count increased by two orders of magnitude, while after terminating the 4-hour mechanical action it decreased gradually. Growing dynamics of microbes constituting the total germ count at 22 °C and 37 °C were almost similar.
The water quality of the Szarvas-Békésszentandrás Dead Körös is generally meso-eutrophic, and meso-saprobic. However, particularly
under higher temperature conditions, the water body may change toward the eutrophic state, even algal blooms could be observed
The present measurements were conducted during a two week peri
the surface, bottom and the middle of the water body. The samples were examined in situ. The oxygen content, the temperature, the pH and
the conductivity were measured by potentiometric methods.
Increasing pH was detected in correlation to the temperature, which indicated a rising photosynthetic activity. Also, the O2
concentration showed high variations, especially, when the fresh water supply from the river was stopped, due to a small flood in the river
These results indicate the increasing eutrophication processes in the deadarm, and the high load and instability of the ecosystem.
The wiser usage of irrigation water is inevitable in the future. Irrigation has very high input cost; therefore, farmers must carry out irrigation with care. Also, the effect of irrigation on crops has a big role in decision making. Modeling provides a possibility to evaluate this effect. AquaCrop, as a crop production simulation model has grea...t potential in this field. The accuracy of tomato biomass yield prediction of the model was tested in this research. For collecting the necessary data, a field experiment was conducted at Szarvas on processing tomato with different water supplies, such as 100% (I100), 75% (I75), 50% (I50) of potential evapotranspiration and a control with basic water supply (C). The relation of the simulation and actual biomass yields was evaluated during the season. Very good correlation was found between the modelled and the actually harvested data. The data for the control and I100 treatments showed higher correlation than the I75 and I50. The relationship for all of the data was moderately strong. Miscalculations occur mostly when the dry biomass yield reaches
7 t ha-1. The accuracy of the model was evaluated with the use of mean absolute error (MAE) and root mean squared error (RMSE) values. The least error was found in the C treatment, which means 0.34 MAE and 0.45 t ha-1 RMSE. The simulation resulted in higher errors in the I75 and I50 treatments.
The nutrient supply of plants is becoming more important in plant protection since the appropriate condition of plants can be ensured by optimal and satisfactory nutrient supply to avoid nutritional deficiency diseases. Due to the extreme weather conditions, plants are forced to face several stress factors, which lea...ds to deterioration of the plant health. The increasing occurrence of droughts poses threat to nutrient uptake through the roots since all the nutrients can be accessible to the plants only if they are in dissolved form in the soil – which is not possible in the absence of water. Therefore, the importance of foliar fertilizer is becoming a more and more significant part of the nutrient supply, because with the help of this technology the development of any nutrient deficiency can be prevented.
In this experiment, we focused on the efficiency of two different foliar fertilizers on maize. Foliar fertilizers were applied two times, once in the stage with 8 leaves and tasseling phenophase of the maize. To verify the efficiency of the foliar fertilizers, the chlorophyll content of untreated and treated plant’s leaves was measured after each application. Moreover, the length and diameter of maize cobs, thousand kernel weight, protein, oil and starch content were also measured, and the results were compared to the untreated (control) ones. According to the results, in all aspects significant differences were observed and due to the laboratory analysis of leaves, in the case of magnesium and zinc supply the foliar fertilizers were able to prevent the development of nutrient deficiency.
The P uptakes of 11 different catch crops on four soils were estimated and compared with changes of double lactate soluble Phosphorus (P(DL)) in soil within a vessel trial. Additionally a model trial with quartz sand was carried out for investigations of the influence of P supply on root parameters. The differences of P uptake in dependence of...the proofed variants were significant. Under a sufficient P supply Buckwheat, Maize and Oil radish had the highest P uptake on sandy soils, on loamy soil also Buckwheat and Maize but Serradella too. Under P deficiency the withdrawals of Phosphorus for Buckwheat, Maize and Oil radish were found to be the highest. In contrast to the sandy soils for the loamy soils no significant relation between the P uptake by plants and changes in the P-DL amount in soil could be found. For all variants the P uptake by plants were higher than the reduction of the P-DL amount in soil. The rate of P-DL content on the total P content in soil reduced while the two trial years only in sandy but not in loamy soils. The P uptake, the root length and the root/shoot relationship depends significantly on the cultivated crop and the added P compound. The added water soluble KH2PO4 caused a higher P uptake but a lower root/shoot-relationship than the water insoluble P compounds.
The third smallest region of Szabolcs-Szatmár-Bereg county is the Nagykálló subregion. Its territory is 377 km2 and its inhabitants number 32.526. Due to the fact that industrial development arrived late, the environmental status of this subregion was saved from serious ecological degradation. The quality of the environment shows a reasonabl...e picture in many respects, comparing to the general survey of the country. The air quality of the region can be qualified as acceptable. Leaving some critical points out of consideration, it is better than the national average. It is favourable from the human environment point of view that the region is free of extremes, and has a balanced climate. The supply of drinking water is above 95%, and the remainsing water requirements are supplied by artesian wells. The water supply network is fully extended in the subregion. The most significant environmental noise source is traffic, including public road traffic, which causes a problem in the town of Nagykálló. The situation of the collection, transportation, and placement of the settlement’s solid wastes show a similar picture to the status of the country. The environmental status of the region is included in the SWOT analysis.
Irrigation involves the risk of secondary salinization on certain areas. The increase of the level of salty groundwater or the application
of poor quality (salty) irrigation water can cause secondary salinization. Irrigation from drilled wells is very characteristic in the small
hobby gardens located around Karcag during the frequently dr
grown in these gardens, hence quite a large amount of subsurface waters are used for irrigation. Water samples were taken from 46 drilled
wells located in the hobby gardens around the town of Karcag and analysed in order to survey the risk of secondary salinization. On the
base of the results of the analyses and some indexes calculated from the chemical parameters of the irrigation waters, it can be established
that none of the investigated wells supply water that is suitable for irrigation without improvement.
Velvetleaf (Abutilon theophrasti Medic.) and Cocklebur species (Xanthium spp.) are more and more dangerous and „difficult to control” weeds in several cultivated plants. The ground cover of these species have became larger in Hungary like other warm-philous species. There are several causes of danger of them, for example: large capability f...or competition, allelopathic effect, keeping on of emergence.
The allelopathic effect of these weeds were examined on sugarbeet (Beta vulgaris L.). Extracts of plants grown under different conditions have several effect on this species.
Abutilon theophrasti plants were grown in perlite to examine the effect of supplying with nutritive materials on production of inhibitors. The water soluble exudates of the shoots grown with no artificial fertilisers inhibit stronger than grown with them. Acid soluble exudates have contrary effect. The exudates made of roots inhibited the sugarbeet less than shoots.
Effect of drought stress on production of inhibitors was examined on Abutilon theophrasti and on Xanthium italicum. The species responded to missing of water different, and the water, acid and basic soluble exudates had different effect, as well.