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The aim of the paper was to evaluate the influence of water stress i.e., different net irrigation water on the allelopathic potential of petunia (Petunia hybrida L.). Water extracts were prepared from aboveground biomass of petunias grown at different net irrigation water (51.5 mm, 91.5 mm and 132.5 mm) in three concentrations (1%, 2.5% and 5%). The experiment was performed under controlled laboratory conditions in Petri dishes and the allelopathic potential of petunia water extracts was assessed by measuring seed germination, root and shoot length, and fresh weight of radish seedlings. The results of the experiment showed a statistically significant allelopathic effect of petunia water extracts on all the measured parameters. The allelopathic potential largely depended on the extract concentration. Petunia extracts of higher concentrations showed a greater negative effect and reduced germination, shoot and root length, and fresh weight of seedlings up to 79.9%, 93.4%, 83.1% and 69.5%, respectively. Positive effect was determined on shoot length and fresh weight of radish seedlings with 1% concentration extracts. As a rule, water stress i.e., net irrigation water did not have a significant effect on the allelopathic potential of petunia. The exception was recorded with the highest extract concentration on the shoot length of seedlings where extracts from petunias grown at 51.5 mm had greater inhibitory effect compared to extracts from petunias grown at 91.5 and 132.5 mm.

Biostimulants are substances that are applied to plant or soil may enhance plants ability to assimilate applied nutrients which results with better development. The aim of this study was to evaluate the effect of biostimulants (Amiksol and Slavol), applied with an organic fertilizer (Stallatico) on the yield and morfological characteristics of strawberry (Fragaria x ananassa Duch.) cultivar Clarity. An experiment was carried out in the 2021 in the open field as a complete randomly design with four replicates, and treatments were: Stallatico (Control), Stallatico + Slavol (T1) and Stallatico + Slavol + Amiksol (T2). Morphological properties were measured in four terms of vegetative growth and fruiting. Twenty plants were selected randomly from each experimental unit to measure the length of canopy (cm), length of roots (cm), total length of plant (cm), as well as weight of canopy (g), weight of roots (g) and total weight of plant (g), number of leaves and stolon and yield (number and weight of fruits). Data were processed by ANOVA and LSD was detrmined at P

Zinnias are ornamental species which are not demanding for breeding, sunny and warm position with loamy well-drained soil is sufficient. The aim of the research was to compare the growth and development of Zinnia (Zinnia elegans Jacq.) in a sunny place, during spring and summer period, in three substrates of various physical and chemical properties (Potgrond H, Florabella and soil). The seeds were sown in PVC containers (Pöpellmann TEKU (EP 2128/20) 28 cm x 21cm x 6 cm) with 20 sowing places (volume 150 ml). After developing four leaves, plants were transplanted into PVC pots (Φ 9 cm) filled with the same substrate. The pot trial was conducted as a randomized complete design with four repetitions. Four weeks later on the developed plants, following values has been measured: plant mass, plant height, plant height above ground, mass of the above-ground part of the plant and the number of leaves. Plants grown in Florabella substrate had higher values than plants grown in Potgrond substrate and soil. Statistically significant difference (P≤0.01) has been found between the values of plants grown in soil and substrates Potgrond H and Florabella.

Maize (Zea mays L.) grain yield largely depends on the amount of plant-available water, nutrients, climatic conditions, soil, and genotype. The grain yield formation is closely related to yield components. The field study was set up near Osijek (2020) on silty clay soil with, loamy texture. The different treatments consisted of two irrigation treatments (a1=irrigated ; a2=rainfed), and two maize hybrids (b1=ossk515 ; b2=po216). Surface irrigation was conducted with the use of furrows, while the soil water content was measured with tensiometers placed at a depth of 30 cm on each irrigation treatment. Net irrigation was 280 mm which completely compensated the crop water requirements on irrigated plots. Significantly (p

The COVID-19 pandemic has significantly affected many segments of human life and activities, including the education system. As a consequence, universities are facing challenges on how to continue with quality teaching where face-to-face classes have opted and remote teaching is introduced. Remote teaching and learning usually carry a stigma of being lower quality than the traditional (face- to-face), which is why it is necessary to evaluate the teaching staff as well as the student experience within remote education. The survey conducted at the Faculty of Agrobiotechnical Sciences Osijek, Republic of Croatia aimed to analyze how students as well as teaching staff were satisfied with remote education during the first wave of coronavirus pandemic. Survey results have shown that most of the students were satisfied with the organization and implementation of remote learning and teaching as well. An interesting observation was the importance of teacher- student interaction as well as the teacher presence during remote education.

With the increasing need for energy, energy studies to be obtained from waste gain importance. In this study, it has been tried to determine the amount of biogas energy that can be obtained from olive pomace (pirina), which is produced by processing oil olives. Numerical maps of pirina amounts and potential biogas energy values and location maps of the proposed pirina processing plant were created. The necessary calculations were made by comparing the obtained results with the relevant literature information. In the study, the current potential biogas energy amount was calculated, maps were created and the electricity and gasoline energy equivalent levels of this energy were tried to be calculated using the 2015-2019 data of the Mediterranean, Aegean and Marmara Regions. The total potential amount of pirina in the research area is 1853375.7 tons and the potential biogas energy amount that can be obtained is 33360762.4 MJ. Pirina, which is the production waste after pressing the olives for oil, can be used for energy production. By using pirina to obtain biogas energy, both the utilization of pirina and the development of the regions will be provided.

Maize seed is during germination and cropping in the open under the influence of different agroecological factors, so high yields will be achieved mainly by sowing quality high vigor seeds. The aim of this research was to determine maize seed vigor by laboratory methods (mass of 1000 seeds, germination energy (GE), standard germination (SG), electrical conductivity (EC) and cold test (CT)) and at the same time examine the influence of genotype of three maize hybrides. The experiment was set up in four repetitions with 50 seeds for each method. A significant difference (P≤0.01) was found between the masses of 1000 seeds of the analyzed hybrids (314g, 307g, 252g). The energy of germination (66%, 63%, 61%), standard germination (94%, 95%, 91%) and cold test (87%, 97%, 83%) did not differ significantly. The determined values of electrical conductivity (7,96 μScm-1g-1, 7,16 μScm-1g-1, 5,23 μScm-1g-1) were significantly (P≤0.01) influenced by hybrids. The analyzed seed was of satisfactory quality or vigor, and the influence of genotype was determined in seeds tested by electrical conductivity method., Sjeme kukuruza je tijekom klijanja i nicanja na otvorenom pod utjecajem različitih agroekoloških faktora pa se visoki prinosi mogu postići prije svega sjetvom kvalitetnog sjemena visokog vigora. Cilj ovoga istraživanja bio je odrediti vigor sjemena kukuruza laboratorijskim metodama (masa 1000 sjemenki, energija klijanja, standardna klijavost, električni konduktivitet i cold test) te ujedno ispitati utjecaj genotipa tri hibrida kukuruza. Pokus je postavljen u četiri repeticije s 50 sjemenki za svaku metodu. Utvrđena je značajna (P≤0,01) razlika između masa 1000 sjemenki analiziranih hibrida (314g, 307g, 252g). Energija klijanja (66%, 63%,61%), standardna klijavost (94%, 95%, 91%) i cold test (87%, 97%, 83%) nisu se značajno (P≤0,01) razlikovali. Utvrđene vrijednosti električnog konduktiviteta (7,96 μScm-1g-1, 7,16 μScm-1g-1, 5,23 μScm-1g-1) bile su pod značajnim (P≤0,01) utjecajem hibrida. Analizirano sjeme imalo je zadovoljavajuću kvalitetu odnosno vigor, a utjecaj genotipa utvrđen je kod sjemena testiranog metodom električnog konduktiviteta.

Marigold (Tagetes spp.) is present in every garden because it is not a demanding plant. Carrot (Daucus carota L.) is one of the ten most important garden vegetables which prefers acid to neutral soils and airy one. The aim of this research was to determine differences in growth and development of French Marigold in two growing media (soil type Eugley and substrate) and to determine quality properties of carrot growth in two different soils (Luvisol and Eugley). The research was randomized, in 4 repetitions for both cultivars. Properties determined for French Marigold were: height, number of branches, number of leaves, and mass of fresh transplant, further more dynamic of growth have been monitored as well as development of flowers due to counting number of rosebuds, number of flowers and their diameter and in the end of research following parameters were measured: height, number of branches, diameter of stalk, mass of the above the ground part of the plant and mass of dry matter of the above of the ground part of plant. Regarding carrot following parameters were measured: diameter of the root, mass of the root, mass of the leaves, number and lenght of the leaves. The collected data have been statistically analyzed by variance analyzes (F test) and differences between treatments have been determined with LSD-test. Significantly higher values (P≤0.01) have been determined for French Marigold growth in substrate regarding those growth in soil and significantly higher values (P≤0.01) for carrots growth in Luvisol soil type.

The spring field pea is one of the most important coarse legumes. This study was carried out to investigate the response of a spring field pea variety to three plant densities (50, 100, and 150 plant m-2) during the 2017 and 2019 growing seasons in eastern Croatia. The field study was set up as a Randomized Complete Block Design (RCBD) in four replications. The results have demonstrated a significant effect of the plant densities and the growing seasons on the seed yield and on the following yield components: plant height and the number of pods/plant. The effect of plant densities on the number of seeds/pod and the thousand-seed weight was not significant. As for a growing season, the highest seed yield, plant height, the number of pods/plant were obtained in the second growing season. Furthermore, a maximum seed yield was recorded at the 150-plant m-2 plant density. This study has demonstrated that planting the spring field pea at different plant densities significantly modifies the spring field pea yield, plant height and number of pods/plant., Jari stočni grašak jedna je od najznačajnijih krupnozrnih mahunarki. Ovo je istraživanje provedeno kako bismo vidjeli reakciju utjecaja različitih gustoća sjetve na jari stočni grašak tijekom dvaju vegetacijskih ciklusa 2017. i 2019. godine u istočnome dijelu Republike Hrvatske. Pokus je postavljen po RCBD sustavu u četiri ponavljanja. Rezultati pokazuju značajan utjecaj gustoće sjetve i godina istraživanja na prinos zrna i većinu komponenata prinosa: visinu biljke i broja mahuna po biljci, osim broja zrna po mahuni i mase tisuću zrna, gdje gustoća sjetve nije statistički značajno utjecala na razlike u vrijednostima istraživanih svojstava. Najveće vrijednosti prinosa zrna, visine biljke i broja mahuna po biljci ostvarene su u drugoj godini istraživanja. Najveći prinos zrna zabilježen je pri gustoći sjetve od 150 biljaka/m2. Istraživanje pokazuje da različite gustoće sjetve značajno modificiraju/utječu na visinu prinosa zrna i komponente prinosa jaroga stočnog graška.

The aim of the study was to determine allelopathic potential of weed root exudates on germination and growth of crops. Field poppy (Papaver rhoeas L.), scentless mayweed (Tripleurospermum inodorum (L.) C.H. Schultz) and redroot pigweed (Amaranthus retroflexus L.) seedlings were grown in soil until 3-leaf stage. After their removal, the soil was re-sown with seeds of barley, soybean and oil pumpkin. The results of the experiment showed that field poppy and scentless mayweed root exudates stimulated root and shoot length, and fresh weight of barley seedlings up to 16.2%, 13.4% and 34.6%, respectively. Redroot pigweed root exudates showed no significant effect on emergence and growth of soybean and oil pumpkin.

The objective of this study was to evaluate the effect of irrigation scheduling (a1: non- irrigated ; a2: 80 – 100 % field capacity) with sprinkler irrigation system and nitrogen rate (b1: 0 kg N ha-1 and b2: 200 kg N ha-1) on yield and quality of two maize hybrids (Zea mays L.). A field study was carried out as randomised block arrangement with three replicates at research field of Agricultural institute in Osijek (2010- 2012). Irrigation was scheduled by measuring the soil water content with granular matrix sensors (GMS). The results showed that efficiency of irrigation scheduling highly depends on weather conditions. During the growing seasons characterized by lack of rainfall, the maximum maize yield was achieved on plots irrigated with the maximum net irrigation (a1 = 7, 47 t ha-1, a2 = 9, 08 t ha- 1, 2011 and a1 = 7, 86 t ha-1 ; a2 = 10, 21 t ha-1, 2012) while during the extremely wet year the maximum yield was achieved on control plots (a1 = 9, 3 t ha-1 ; a2 = 9, 14 t ha-1). As for quality of the grain, the protein content decreased with higher net irrigation which was opposite to the starch content. The effect of nitrogen rate and hybrid was year dependent.

During the 3-years study maize (Zea mays L.) production in the eastern Republic of Croatia suffered a great losses due to periods of flood (2010) and droughts (2011 and 2012). Excessive amount of water as well as lack of it caused variation of yield and efficiency of irrigation scheduling. Irrigation treatments included a rainfed treatment and irrigation up to soil water content 80-100% of field capacity. The nitrogen fertilization treatments were 0 (control) and 200 kg N/ha. The analyzed crop productivity parameters were 1000-grain mass and grain yield, in two hybrids. The irrigation significantly increased maize grain yield in dry years, while in extremely wet year 2010 yield in the irrigated plot was reduced doe to stress caused by excessive rainfall and over- irrigation. Both tested hybrids responded positively to the combination of nitrogen fertilizer and irrigation. Regardless of if expressed on fresh tissue or dry weight basis, proline content in maize leaf did not show clear effect of irrigation treatment, whereas nitrogen fertilization stimulated this amino acid accumulation. There was a close relationship established between proline in leaf dry matter in both growth stages and 1000- grain mass, as well as a weak relationship between this parameter at flowering and final grain yield.

Prinos i komponente prinosa kukuruza su pod velikim utjecajem agroekoloških uvjeta, genotipa i njihove interakcije, kao i agrotehničkih uvjeta. Cilj rada je bio utvrditi reakciju hibrida kukuruza na mineralnu gnojidbu u proizvodnim uvjetima 2010. godine na području istočne Hrvatske. Pokus je postavljen na tlu siromašnom raspoloživim fosforom i kalijem. Ispitivana su tri hibrida FAO skupine 400 na dvije varijante gnojidbe: G1 (124 kg ha-1 N, 90 kg ha-1 P2O5 i 135 kg ha-1 K2O) i G2 (179 kg ha-1 N, 120 kg ha-1 P2O5 i 180 kg ha-1 K2O). Iako je 2010. godina bila iznad prosječno vlažna, sa stajališta uzgoja kukuruza možemo je okarakterizirati kao relativno povoljnu zbog dobre opskrbljenosti vodom tijekom vegetacije kukuruza. Utjecaj gnojidbenih varijanti i hibrida na prinos zrna je bio nesignifikantan, a naglašenija gnojidba značajno je utjecala samo na masu 1000 zrna, dok je učinak hibrida bio signifikantan za masu 1000 zrna, sklop i dužinu klipa.

„IRRI - The Irrigation Project“ is by EU through IPA II Cross-Border Program Croatia – Bosnia and Herzegovina and implemented by the Municipality of Lovas on the Croatian side and Municipality of Odžak on the Bosnian and Herzegovina side together with project partners: Vukovar-Srijem County, Municipality of Tompojevci, Associations of Users of the Opatovac and Tompojevci Irrigation System, Municipality of Šamac and Association Independent Office for Development. The project seeks to increase incomes by reducing the effects of droughts which in crossborder region occur once in three to five years. The average yield of primarily vegetables, fruit and other crops is low comparing to European Union countries. Also one of the major problems is lack of education, basic knowledge and training what leads to the fact that farmers are not involved in the growing global irrigation trend. Therefore, the project is intended to develop demonstration irrigated fields through investments that are cost effective, environmentally and socially sound and beneficial to the rural poor. Special accent is put on education where conducted series of workshops and field trainings will enable the transfer of the latest knowledge and technologies in the field of irrigation and establish a number of experts in irrigation. All results of project activities are presented to the wider audience through events, presentation and demonstration fields. The aim of the assignment is to contribute to increase crop productions and raise farmers’ incomes in the municipalities Lovas and Tompojevci through supporting of production of agriculture producers by introduction of the system for irrigation, enhancing of knowledge of farmers and expertise of technicians and increasing of cooperation and public awareness in irrigation.

The stationary field experiment was conducted in spring of 2004 on Pavlovac (Bjelovar- Bilogora County-Croatia) very acid soil (pH in 1n KCl = 3.80) by the application of NPK 10:30:20 fertilizer as follows (kg ha-1): a = 0 (the conventional fertilization) ; b = a + 416 ; c =1249 ; d = 2028 ; e = 2916 ; f = 3748. Differences of N amounts added by fertdolomite were equalized by CAN (calcium ammonium nitrate: 27% N). The experiment was conducted in four replicates and the basic plot size was 77 m2. Two replicates of the experiment was limed in autumn of 2007 by granulated fertdolomite (24.0 % CaO + 16.0 % MgO + 3.0 % N + 2.5 % P2O5 + 3.0 % K2O) in amount 10 t ha-1. Two subplots from each replicates were harvested in order to obtain four replicates of grain yield data for each treatment. In this study was shown survey grain yield of field crops grown in rotation for 5–year period 2008– 2012 (maize – maize – soybean – maize – winter wheat). Mean yields of the field crops in the experiment were as follows (t/ha): 11.64, 10.70 and 9.02 (maize 2008, 2009 and 2011, respectively), 3.57 (soybean 2010) and 7.59 (wheat 2012). Response to liming was depended on the growing season (year effect) and field crop. As affected by liming, yields of maize were significantly increased for 5% (2008 and 2009) and for 8% (2011). Also, yields of wheat were similar for unlimed and limed plots in 2012 (7.64 and 7.54 t/ha, respectively). However, soybean responded to liming in 2010 by yield increases for 18% (3.28 and 3.85 t/ha, respectively).

Maize is main field crop on arable lands in Croatia. Climatic changes, particularly temperature regime and precipitation quantities and their distribution during growing season, had often adverse effects on maize yield. With that regard, irrigation of maize crops in critical periods is useful with aspect of alleviation yield variations among years. Also, acid soils covering third part of agricultural soils in Croatia (about 832 thousand hectares) and correction of pH by liming is important factor increase and stabilization of yield among years. Aim of this study was review of irrigation and liming effects on maize yield in the eastern Croatia. Region of the eastern Croatia covering 12454 km2 or 22.0% of the state territory. This region is “granary of Croatia” because about 75% of wheat and 50% of maize harvested areas of the country are situated in this region. As affected by irrigation, maize yields in the experiment on Agricultural Institute Osijek since 2000 were increased average for 20%, while under drought conditions of three growing seasons (2007, 2011 and 2012) yield increases were 32%, 36%, and 47%, respectively. Soil improvement by liming by increasing rates of carbocalk (by-product of sugar factory containing about 43% CaO and about 6% of organic matter) up to 60 t ha-1 was also useful management practice, because in two experiments maize yields were increased up to 25% (4-year average). However, for satisfied yield increases for 16% in both experiments was adequate the lowest rate of applied carbocalk in the amount of 15 t ha-1.

The purpose of irrigation scheduling is to make a decision when and how much water apply to the field. There are many advantages of irrigation scheduling and one of the most important is to maximize irrigation efficiency by saving of irrigation water and energy as well. Also, there are different methods for irrigation scheduling which are consisted on several criterion. One of the most common used criterion in scientific research and agronomic practice is monitoring of soil moisture content during the period of growth. The discussion in this paper is limited to the use of electrical resistance blocks in irrigation scheduling. Furthermore, the efficiency of electrical resistance blocks in extreme weather conditions. The analysis of results indicate that proper irrigation scheduling has important role in preserving water and achieving high yields of maize, especially in extreme weather condition. Furthermore, application of electrical resistance block is useful tool in indirect measuring of resistance and soil water content.

The long-term stationary field experiment with irrigation and nitrogen fertilization has been started in spring of 2006 on the experimental field of Agricultural Institute Osijek (Osijek- Barannya County, Croatia). The experiment was duplicated for maize – soybean rotation. Soil moisture maintained by two steps of irrigation (from 60-100% and 80-100% of field water capacity, while not irrigated plot was the control. N fertilization treatments were as follows: the control (non-fertilized for 2006- 2009 period), 100 kg N ha-1 and 200 kg N ha-1. Nitrogen was added in two equal portions (ploughed in autumn and incorporated in soil by seedbed preparation treatment in spring) in form of urea (46% N).P and K fertilization was equal for all treatments including N- unfertilized plots. Aim of this study was testing of nitrate leaching in 2006 – 2009 period. Percolate was collected in Ebermayer, s lysdimeter reservoir and pumped by mechanical pumps 5 to 7 days after the rain or irrigation treatment. Nitrate was determined spectrophotometricaly in laboratory of Osijek Water-System by 2, 6- dimethylphenol method. Average NO3-N leaching in tested 4-year period was 5.82 kg N/ha. The ranges of N leaching were from 2.65 to 10.10 kg N/ha (year effect), from 4.05 to 7.42 N/ha (irrigation effect: 4-year average) and from 2.43 to 8.81 mg N/ha (fertilization effect: 4-year average). The lowest NO3-N leaching was under non-irrigated and N-unfertilized conditions (4-year average: 2.05 kg N/ha), while N leaching under conditions of the treatment the higher rate of irrigation and fertilization 200 kg N/ha was 11.97 kg N/ha.

Seed producers regularly control seed before the distribution. Some of those methods are standard (standard germination – SG, germination energy – GE, 1000 grain mass) but some which would show reaction of the seed on unfavorable conditions in the field are not regular (cold test – CT, electrical conductivity – EC). The aim of this study was to investigate seed vigor of four cultivars of green pea by all early mentioned methods. Investigation has been conducted on College of Slavonski Brod with these cultivars: Telefon, Kelvedon Wonder, Wonder van America and Rondo. Standard seeds from local agricultural shop with expired date 2013 were used. The best results with 1000 grain mass, standard germination-SG and germination energy- GE had cultivar Rondo. Cultivar Rondo showed the worst germination on Cold test-CT. Increase of imbibition temperature (10 °C, 20 °C, 30 °C) result with increase of EC value (33.6 μS cm-1 g-1 and 45.2 μS cm-1 g-1respectively ). Results pointing on decrease of seed quality on relation between producer and user.

The field experiment was set up at the trial field of Agricultural institute in Osijek as split split-plot scheme in year 2012. The goal of study was to evaluate the effect of different irrigation and nitrogen fertilizers levels on nitrate- nitrogen leaching in maize filed. The experiment included three irrigation levels (A1= non irrigated ; A2 = 60 to 100 field water capacity (FWC) ; A3 = 80 to 100 FWC) and three nitrogen fertilizers level (B1 = 0 kg N/ha, B2 = 100 kg N/ha, B3 = 200kg N/ha) with two replications. Lysimeters were set up at 80 cm depth on each irrigation and nitrogen fertilizers level (A, B, AxB). The water samples from lysimeters were taken three times during vegetation, after irrigation or precipitation. Maximum NO3¯ leaching out soil layer was 79.28 mg NO3¯ on plots irrigated with the highest amount of water (A3 = 80 to 100% FWC) and fertilized with maximum N (200 kg N/ha).

The field trial of phosphorus fertilization was conducted on calcareousalluvial alkaline soil of Posavina Canton (Bosnia and Herzegovina) in spring 2011: a) unfertilized ; b) basic fertilization = 75 P2O5 kg ha-1 ; c) a + 200 P2O5 kg ha-1 ; d) a + 400 P2O5 kg ha-1 ; e) a + 800 P2O5 kg ha-1 ; f)a +1200 P2O5 kg ha-1.The experiment was conducted in four replicates (basic plot 60 m2). In this study maize (hybrid OsSK596) response (the 2011 growing season) was shown. Mean yield of maize grain of the fertilization treatments (b-e) in level of 11.03 t ha-1 was relative low due to less favorable weather conditions. Maize yield increases were 8% and 53% by f:b comparison and f:a comparison, respectively.

Soybean as wide spread crop in eastern Croatia is planted on 45888 ha with grain yield 2.0 t ha-1. The treatments in the field trials were growing season (GS, main factor, A: A1=year 2010 ; A2= year 2011 ; A3= year 2012), irrigation rate (IR, sub factor, B: B1=control, no irrigation, B2= soil water content maintained from 60% to 100% of field water capacity (FWC), B3= soil water content maintained from 80% to 100% of FWC) and soybean varieties (sub sub-factor, C: C1=Lucija, C2=Vita, C3=Ika and C4=Tena, created at Agricultural Institute Osijek). The objective of this study was testing irrigation and genotype impact on grain yield, oil and protein content at the soybean in the no nitrogen fertilization soil conditions. Therefore, the nitrogen potential in three climatically different growing seasons in natural, field conditions has been tested. Mean soybean grain yields were 3436 kg ha-1, 3678 and 3633 kg ha-1 in year 2010, 2011 and 2012, respectively. Irrigation and soybean variety had statistically significant impact on soybean grain yield, while growing season not. Growing season, irrigation and soybean variety resulted by statistical significant impact on oil content, while growing season on protein content, only.

Until 2003 there were 9 275 ha under irrigation, which represents 0.86% of arable lands in Croatia. Irrigation systems were unorganized and conducted without plans with undefined rights and obligations of the participants. Surfaces under irrigation were small and the consequences of drought were measured in millions. Croatian government in 2005 has accepted the National Project of Irrigation and Land and Water Management in the Republic of Croatia. Main goal of the project is to increase surfaces under irrigation to 65 000 ha until 2020, which represents 6% of arable lands in Croatia. It would take planed approach to achieve this plan, and is possible thru building of infrastructure and with enlargement of production surfaces of the farmers. Until 2012 irrigated surfaces were increased up to 12 000 which is less then planed.

Global climatic changes have considerably impacts on field crops growing, mainly by increasing trend of temperature and more frequency of drought stress in the critical stages of growth. Irrigation is direct measure for improvement of water status in soil and alleviation of drought stress effects. Stationary field experiment with irrigation and nitrogen fertilization was started on Agricultural Institute Osijek in spring 2006. Soil moisture was maintained by irrigation in range from 60% to 100% (A2) and 80% to 100% (A3) of field water capacity (FWC) and no irrigation treatment (A1, control). Three rates of nitrogen were used: B1=control (non- fertilized), B2=100 kg N ha-1, B3=200 kg N ha- 1. Aim of this paper is analyse variation of maize grain yields in the period 2006-2011 with rainfall and temperature regime in connection with set treatments. In the 3-month June-August period precipitation in Osijek were in range from 105 to 377 mm and mean air- temperature from 21.0 to 22.8 degree. In accordance with these parameters status, need for irrigation was in range from 40 to 160 mm and from 80 to 280 mm, for maintenances of soil water in ranges 60-100% and 80-100% of FWC, respectively. Maize yield increases as affected by irrigation (means of two irrigation treatments) were as follows: 11% (2006), 18% (2007), 11% (2008), 8% (2009), 0% (2010) and 30% (2011). Nitrogen fertilization resulted also by yield increases of maize for 21% (B2) and 36% (B3).

In decade period from year 2000 to 2009, maize yield in Croatia varied from 4.2 t ha-1 (2003) to 8 t ha-1 (2008). Yield variation is mainly influenced by unfavourable weather conditions for maize production meaning lack of precipitation and high mean air temperatures. In addition to that, unfavourable distribution of precipitation during vegetation season leads to yield decreasing and quality distortion of maize grain. In this paper five vegetation seasons (2000, 2007, 2008, 2009 and 2010) with quite different weather conditions for maize production have been analyzed in order to examine the influence of weather conditions meaning draught, flood and irrigation practice as well (meaning soil water content) to maize production. Irrigation practice has become justified and essential agrotechnical measure which minimizes damage of water deficit during a critical growth stage of plant and it ensures high yield of maize grain but in this period of climate changes it is necessarily to maintain existing melioration systems and to invest in new one to.

The experiment was set up as split-split plot method with three repetitions in two vegetation seasons (2006-2007) in order to determine the influence of irrigation treatment (A1-control, A2- 60% to 100% field water capacity (FWC), A3-80% to 100% FWC), N fertilizer (B1-control, B2-100 kg N ha-1, and B3-200 kg N ha-1) and genotype (C1= OSSK 596 ; C2=OSSK 617 ; C3= OSSK 602 ; C4 = OSSK 552) on yield and yield parameters (cob lenght, cob weight, kernel number, kernel weight and number of rows per cob) of maize. Irrigation treatment have very signifcantly increased yield in both tested years. Also, irrigation treatment increased row nubmer/cob, kernel weight (KW), kernel number (KN), cob weight (CW), (P>0.05) in 2006, CW and KN in 2007 (P>0.01). N fertilization had a very significant (P>0.01) impact on all testeted factors in both years of research. Genotype showed very significant impact on all tested factors in year 2006, although in dry vegetation season 2007 statistical singficant was showed only to yield and kernel number.

The aim of this paper was to determine the distribution and characteristics of hydromorphic soils, class pseudogley soil, soil type pseudogley of County of Slavonski Brod- Posavina. According to Basic Soil Map of the Republic of Croatia (scale 1:50000) and previous studies in these investigation area 17 soil types were determined, of which 10 belong to automorphic soils, and 7 to hydromorphic soils. Pseudogley takes about 36184, 4 ha in County of Slavonski Brod-Posavina (Brodsko- posavska County). The texture of these soils is silty clay loam in surface and subsurface horizon with content of clay between 10, 4 to 36, 1%. Soil structure agregates are very unstable. Pseudogley soils in this area are characterized by a low to very low air holding capacity and low to medium retention water capacity, also water drainage is low to absolutely watertight. It was determined that soils are vary from very to low acid (pH KCl 3, 96 to 5, 66) and show low to moderate supplies of potassium. Supplies of phosphorus are very variable (0 to 30 mg/100 g soil), also content of soil organic matter is in wide range (from 0, 2% to 7, 02%). Main limiting factors of pseudogley for plant production are presence of watertight pseudogley (g) horizon, high density, low infiltration, low air capacity, high soil plasticity and low phosphorus and potassium content.

Field experiments were set up at Agricultural Institute Osijek (Croatia) as split split-plot method with three repetitions thru two growing seasons (2008-2009). Soil type at trial field is classified as eutric cambisol, non calcareous. Soil retention water capacity was close to the value of FWC (36.6% volume). Aim of this research was to determine the influence of irrigation, nitrogen rate, and maize genotype on yield and yield parameters of maize (cob length, cob weight, grain number per cob, grain weight per cob, and number of rows per cob). Irrigation (A) as main factor had treatments as follows: A1-control treatment, A2-soil water content from 60% to 100% field water capacity (FWC), A3-80% to 100% FWC. Nitrogen fertilization was sub factor (B1- control treatment, B2-100 kg N ha-1, B3-200 kg N ha-1) while the sub sub-factor (C) was maize genotype (hybrids FAO group 500 and 600). Irrigation treatment resulted by statistically significant increasing in grain yield 8 159 kg ha-1 (A1) to 9 097 kg ha-1 (A3) in year 2008 and 9 788 kg ha-1 (A1) to 10 315 kg ha-1 (A3) in year 2009. N fertilizers have significantly increased yield 7 689 kg ha-1 (B1) to 9 336 kg ha-1 (B3) in 2008 and from 9 318 kg ha-1 (B1) to 11 119 kg ha-1 (B3) in year 2009. Grain yield significantly varied thru tested genotypes from 8 336 kg ha-1 (C3) to 9 137 kg ha-1 (C4) and from 9 831 kg ha-1 (C1) to 10 704 kg ha-1 (C3) in years 2008 and 2009. Treatments resulted with significant differences in yield parameters.

Nutrient transport down the soil profile, especially Nitrogen (N) varies considerably depending on soil properties and climate. Insufficient application of N fertilizer can result with the lower yield while excessive application of N could result by losses of it and pollutions. The consequences of N leaching to a deeper soil layers and subsurface water are manifesting as negative influence on human health and harmony of ecosystem. Field experiment was setup on trial fields of Agricultural Institute Osijek as split-split plot method in three repetitions during the period 2006 and 2008. Maize yield and pollution from N fertilizer were tested in irrigated and N fertilized condition with wide spread maize hybrid in Croatia, OSSK 552, created at Agricultural institute Osijek. For collecting the leachate Ebermeier's lysimeters were used. The leachate was analyzed in laboratory – the content of nitrate, nitrite and ammonium forms of nitrogen. Irrigation treatment was significant for both years of experiment with yield increasing for 13%, while the nitrogen fertilizer increased maize yield for 16%. Larger amount and concentration of leachate comes as result of irrigation intervals with the highest amount of water, fertilization with the larger nitrogen doses, and the highest amount of precipitation during vegetation season.

The research has been set up as split-split plot method in three repetitions at trial fields of Agricultural institute in Osijek during growing season 2009. Irrigation is main factor: A1 = control, A2 = 60-100% field water capacity (FWC), and A3 = 80-100% FWC. N fertilization was applied as follows: B1 = control, B2 = 100 kg N ha-1 and B3 = 200 kg N ha-1. Two maize hybrids (OSSK 596 and OSSK 617, FAO 500 and FAO 600) have been tested. Analysis of variance showed statistically very significant impact of hybrid on specific leaf area, specific leaf weight and leaf water content. Significant morphological and physiological indicators have been used for determination of correlation analysis between yield and indicators.