Search

U sedmogodišnjem periodu (2011. – 2017.) na 20 lokacija u Republici Srbiji provedeni su sortni makro pokusi s 9 hibrida kukuruza Instituta za kukuruz „Zemun Polje“ kako bi se analizirala stabilnost njihova prinosa. Ispitivani hibridi pripadali su FAO grupama 300 – 700, većina ih je novije generacije, ali jedan dio pripada komercijalnim hibridima raširenim u proizvodnji. Iz FAO grupe 300 u pokusima je bio zastupljen hibrid ZP 341, FAO grupe 400 hibridi ZP 427 i ZP 434, iz FAO grupe 500 hibridi ZP 548, ZP 555 i ZP 560, iz FAO grupe 600 hibrid ZP 666, te iz FAO grupe 700 hibrid ZP 606. Tijekom perioda istraživanja bile su dvije izrazito sušne godine (2012. i 2017.) kao i dvije godine s nadprosječnom količinom oborina tijekom vegetacijskog perioda kukuruza (2014. i 2016.) što je veoma važno za analizu stabilnosti prinosa pojedinih hibrida u različitim proizvodnim uvjetima. Stabilnost prinosa izračunata je korištenjem metode linearne regresije po Eberhartu i Russelu gdje se na osnovu vrijednosti regresijskog koeficijenta (bi) može ocijeniti stabilnost prinosa, kao i prilagođenost ispitivanih hibrida povoljnijim ili lošijim uvjetima uzgoja. Najveću stabilnost prinosa imali su hibridi ZP 555 i ZP 548. Oni su pokazali najmanje variranje prinosa u različitim uvjetima uzgoja. Hibridi prilagođeniji uzgoju u povoljnijim uvjetima bili hibridi ZP 666 i ZP 606, dok su prilagođeniji nepovoljnijim uvjetima uzgoja bili hibridi ZP 341 i ZP 427. During the seven years period (2011 – 2017) at 20 locations in Republic of Serbia 9 corn hybrids of Maize Research Institute „Zemun Polje“ were tested in the aim of analyzing the yield stability. Tested hybrids was from FAO groups 300 – 700, most ly there are hybrids of new generation, but some of them are commercial hybrids spread in production. From FAO group 300 i trials were included hybrid ZP 341, from FAO group 400 hybrids ZP 427 and ZP 434, from FAO group 500 hybrids ZP 548, ZP 555 and ZP 560, from FAO group 600 hybrid ZP 666, and from FAO group 700 hybrid ZP 606. During the testing period there were two extremely dry years (2012 and 2017) and two extremely wet years (2014 and 2016) what was very important for analysing yield stability of some hybrids at various production condition. Stability of yield was calculated using the method of linear regression of Eberhart and Russel where on the basis of regression coefficient (bi) is it a possible evaluate the yield stability and adaptability of tested hybrids to better or worse production conditions. The highest stability of yield had the hybrids ZP 555 and ZP 548. They showed the lowest variation in yield at various production conditions. Hybrids with the highest adaptation to favourable production conditions were ZP 666 and ZP 606, while the hybrids the highest adaptation to unfavourable production conditions were ZP 341 and ZP 427.

Maize is a row crop with growing cycle from spring to autumn which makes weeds as limiting factor in production, especially when herbicides are not properly applied. The conventional maize production in Serbia means sowing on 70 cm row distance, application of standard forms of nitrogen, and pre-emergence herbicide treatment. The advanced technology for modern maize hybrid production that includes sowing with 50 cm row distance and slow-realizing urea and post emergence herbicide application, was tested. The experiment was conducted in the MRI Zemun Polje, Belgrade, during 2014-2016. Maize newly developed hybrid ZPSC 388 was sown with the application of standard urea and slow-realizing urea (triamid UTEC (n-butil) tiofosfat (NBPT), Eurochem Agro, Germany), both applied at the beginning of maize development. Within each N source, maize was grown with 50 cm and 70 cm row spacing. The herbicide treatments included: control with no herbicides, a pre-emergence treatment of S metolachlor+mesotrione (960 g ha-1 + 120 g ha-1 a.i.) and post-emergence application of nicosulfuron+mesotrione (40 g ha-1 + 120 g ha-1 a.i.). Three weeks after herbicides application, the dry biomass of uprooted weeds from 1 m2 (DBW) was measured, while maize harvest index (HI) and grain yield (GY), were evaluated when plants were fully matured. The DBW as well as HI and GY of maize were highly dependent on the meteorological conditions. Statistical analysis showed that average DBW was significantly lower in the post-emergence treatment (33.6%) than with pre-emergence application of herbicides, while row spacing and urea form did not affect weed infestation level. The HI and GY have been influenced significantly only by maize row spacing and reached higher values in 70 cm (for 4.7% and 19.9%, respectively). Results indicate that, despite weed biomass reduction, maize in Serbia still should be grown with 70 cm row spacing in order to achieve high biomass and grain yield.

Maize (Zea mays L.) is the highest ranking crop in terms of area and production in Serbia. During the whole growing period maize requires high temperatures and sufficient amounts of precipitation. High yields could be achieved on loose and porous soil with good capacity for water and those containing easily-accessible nutrients. The agro-ecological conditions for maize production differ over various regions of Serbia and meteorological parameters can seriously influence maize cultivation. Natural hazards, such as the occurrence of frosts, heavy rains in spring, floods, storms, hail, droughts, cause stress and to a significant degree can reduce or destroy maize yields. The application of appropriate cropping practices mitigates adverse effects of climate and soil and provides conditions for the maximum utilisation of the genetic yielding potential of maize hybrids. A system of measures that encompasses proper crop rotation, primary soil tillage, fertilisation, sowing date and density, irrigation, as well as some ecological measures such as intercropping or cover crops, are basic prerequisites for successful production of maize in Serbia. Many producers do not use these measures at the appropriate level even though results shows that fertilisation can improve maize yields from 7.87 t/ha to 10.00 t/ha under rainfed and from 9.42 t/ha to 12.32 t/ha under irrigated conditions. Irrigation can also increase maize yields by more than 30%. In the study, good agricultural practices as components of an improved technologies that could help to reduce the impacts of natural hazards and obtain high and stable yields, are identified and validated.

Савремена пољопривредна производња за императив има економичну производњу здравствено безбедне хране, уз очување земљишта и воде, као природних ресурса. Примена редукованог наводњавања препознаје се као једана од могућности за смањење негативних утицаја суше са једне стране и уштеде воде и смањење утрошка енергије и радне снаге у пољопривредној производњи, са друге стране. Основни циљ истраживања предвиђених овом докторском дисертацијом јесте дефинисање потреба кукуруза за водом и рационалног режима наводњавања земљишта редукованим нормама заливања, и одређивање реалне евапотранспирације у условима водног стреса, која обезбеђује најбољу ефикасност коришћења воде наводњавања у дотичним агроеколошким условима. Циљ је такође да се утврди која је то најповољнија густина сетве у условима редукованог наводњавња, којим ће се остварити и високи приноси и ефикасност коришћења воде. Истраживања су обављена на експерименталном пољу за наводњавање Института за кукуруз “Земун Поље” у периоду од 2002. до 2005. године. Есперименталне парцеле величине 44,8 m2 различитих варијанти истраживања биле су постављене по шеми случајног блок распореда у четири понављања. Гајен је хибрид кукуруза ЗП 677 ФАО 600 групе зрења, у три различите густине: G1=54900 биљ.∙hа-1; G2=64900 биљ.∙hа-1 и G3=75200 биљ.∙hа-1. Примењено је пет режима наводњавања: Wо– природни водни режим земљишта (без наводњавања), Wi1, Wi2,Wi3 и Wi4 засновани на бази међусобног односа реалне (ЕТa) и референтне евапотранспирације (ЕТо) 0,4:1, 0,6:1, 0,8:1 и 1:1, респективно. Наводњавање је обављано методом орошавања, а додате количине воде наводњавањем мерене су водомером, за сваку варијанту проучавања. Током истраживања свакодневно је методом Penman-Monteith обрачунавана референтна евапотранспорација (ЕТо), динамика влажности земљишта мерена је декадно, термогравиметријским методом... Cost-effective production of organic food with preservation of soil and water, as natural resources, is the imperative of contemporary agricultural production. The application of deficit irrigation is recognised as one of the options for reducing adverse effects of drought on the one hand and saving water and reducing in both energy consumption and labour in agricultural production on the other hand. The main aim set up in this doctoral dissertation was to define water requirements of maize plants and the rational soil water status ensured by deficit irrigation and to determine actual evapotranspiration under conditions of water stress that would provide the best irrigation water use efficiency under given agro-ecological conditions. The objective was also to establish the most favourable sowing density under conditions of deficit irrigation due to which high yields and efficient water use would be achieved. The studies were carried out in the experimental field for irrigation of the Maize Research Institute, Zemun Polje in the 2002-2005 period. The experimental plot size was 44.8 m2. The plots with various variants of studying were set up according to the four-replicate randomised complete block design. The maize hybrid ZP 677 of FAO 600 was grown in the following three sowing densities: G1=54,900 plants hа-1; G2=64,900 plants hа-1 and G3=75,200 plants hа-1. The following five irrigation regimes were applied: Wо – rainfed regime of the soil (without irrigation), Wi1, Wi2,Wi3 and Wi4 regimes based on the ratio of actual evapotranspiration (ЕТa) to reference evapotranspiration (ЕТо) that amounted to 0.4:1, 0.6:1, 0.8:1 and 1:1, respectively. The sprinkling irrigation method was applied, while irrigation water amounts were measured by a water gauge for each variant of studying. Reference evapotranspiration (ЕТо) was daily computed by the Penman-Monteith method, while the dynamics of soil moisture was measured by the gravimetric method each ten days. During the growing season, phenological periods were registered and morphological traits of maize were monitored. After harvest, the ear length, number of kernel rows per ear and the number of kernels per row, as well as the 1000-kernel weight were determined...

In this paper the influence of hybrid on the particular traits of maize seed was examined. Four maize hybrids were tested on four locations. Analysed traits were: yield, ratio of seed fractions and germination by fractions. Yield differed among the hybrids. Hybrid ZP 427 achieved the highest yield per area unit (5,522.4 kg/ha), and ZP 434 had the lowest, with 2,357.8 kg/ha. The ratio of seed fractions differed significantly depending on the hybrid. Based on the results we can conclude that hybrid ZP 600 had the best ratio of fractions, with 76.2 % of small fraction. In all tested hybrids large fractions had higher germination efficiency. The highest average germination was observed in large fractions of hybrid ZP 666 (97.87 %), while the lowest germination was at small fractions of ZP 600 (92.38 %). On all three examined traits there was significant effect of both genotype and location, as well as their interaction. U radu je ispitivan uticaj hibrida na pojedine osobine semena kukuruza. Istraživanjem su obuhvaćena četiri ZP hibrida kukuruza različite genetičke osnove, čija je proizvodnja bila na četiri lokacije. U radu je analizirana proizvodnja semena pomenutih hibrida u 2014. godini. Ispitivane su sledeće osobine: prinos, procentualni odnos krupnih i sitnih frakcija semena i klijavost po frakcijama. Dobijeni rezultati su testirani analizom varijanse, a međusobna poređenja su vršena pomoću LSD testa. Hibridi su se razlikovali po visini prinosa. Hibrid ZP 427 ostvario je najveći prosečan prinos po jedinici površine od 5.522,4 kg/ha, a najniži prinos je imao hibrid ZP 434 koji je ostvario 2.357,8 kg/ha. Procentualno učešće krupnih i sitnih frakcija bilo je vrlo različito u zavisnosti od hibrida. Hibrid ZP 427 imao je 90% krupne i 10% sitne frakcije, hibrid ZP 434 ostvario je 70,8% krupne i 29,2% sitne frakcije, kod ZP 666 zabeleženo je 44,5% krupne i 55,5% sitne frakcije i na kraju ZP 600 imao je 23,8% krupne i 76,2% sitne frakcije. Na osnovu toga se može zaključiti da je kod hibrida ZP 600 zabeležen najbolji odnos frakcija, tj. sitnih frakcija ima 76,2% što daje više setvenih jedinica po hektaru. Što se klijavosti tiče, kod svih ispitivanih hibrida, krupne frakcije su imale veći procenat klijavosti. Najviša prosečna klijavost je zabeležena kod krupne frakcije hibrida ZP 666 (97,87%), dok je najniža klijavost bila kod sitne frakcije hibrida ZP 600 (92,38%). Kod ispoljavanja sve tri ispitivane osobine značajan uticaj su imali genotip i lokacija, kao i njihova interakcija.

Five-year studies on the duration of the growing season of the VI generation of ZP maize hybrids were carried out on slightly calcareous chernozem at Zemun Polje in the 2009-2013 period. The following hybrids were observed: ZP 427 (FAO 400), ZP 555 and ZP 560 (FAO 500) as well as ZP 600, ZP 606 and ZP 666 (FAO 600) in the optimum sowing densities of 55- 65,000 plants x ha-1. The average duration of the growing season ranged from 121 days (ZP 427 - medium early maturity hybrid) over 125-128 days (ZP 555 and ZP 560 - medium maturity hybrids) to 130-134 days (ZP 600, ZP 606 and ZP 666 medium late maturity hybrids). The necessary heat unity sum for the medium early maturity hybrid, medium maturity hybrids and medium late maturity hybrids amounted to 1,315 oC, 1,315-1,363oC and to 1,425-1,461oC, respectively. This is a good indicator for the appropriate agroecological regional distribution of ZP hybrids. Obavljena su istraživanja dužine vegetacije šest hibrida kukuruza najnovije (VI) generacije ZP hibrida u agroekološkim uslovima Zemunskog polja u petogodišnjem periodu (2009-2013). Ispitivani su sledeći hibridi: ZP 427 (srednje rani), ZP 555 i ZP 560 (srednje stasni) i ZP 600, ZP 606 i ZP 666 (srednje kasni) FAO grupe zrenja 400,500 i 600. Dužina vegetacije bila je od 121 dan (ZP 427), 125-128 dana (ZP 555 i ZP 560) do 130-134 dana (ZP 600, ZP 666 i ZP 606). Ukupna suma toplotnih jedinica (efektivnih temperatura) bila je od 1.315o C do 1.461o C i to je polazna osnova za savremenu agroekološku rejonizaciju gajenja ZP hibrida FAO 400-600, tj. do 400-600 m n.v.

With the aim to create favorable conditions for the plant development, the studies on effects of different tillage systems on maize yield and porosity changes of the irrigated chernozem ploughing layer were performed. The objective of the studies was conventional tillage (disc harrow, plough, seedbed conditioner), reduced tillage (rotary shredder) and direct drilling (direct drill seeder). The analysis of variance performed for the yield shows significant differences among observed tillage systems carried out on chernozem. The highest yield of 12.39 t·ha-1 was obtained by conventional tillage. Yields obtained by reduced tillage and direct drilling were lower and amounted to 11.03 t·ha-1 and 10.03 t·ha-1, respectively. The conventional tillage system provided the most favorable porosity with the average value of 51.08%. With no statistical significant differences, the porous to solid phase ratio was somewhat less favorable in soil tilled by the rotary shredder (50.47 vol.%), while it was significantly lower in the variant of direct drilling (48.12 vol.%). U cilju stvaranja povoljnih uslova za razviće biljke, obavljena su proučavanja uticaja različitih sistema obrade na prinos kukuruza i ukupnu poroznost oraničnog sloja navodnjavanog černozema. Predmet istraživanja bila je konvencionalna obrada (tanjirača, plug, setvospremač), redukovana (rotositnilica) i direktna setva (sejalica za direktnu setvu). Analiza varijanse prinosa pokazuje signifikantne razlike između proučavanih sistema obrade černozema. Najbolji rezultati prinosa ostvareni su konvencionalnom obradom-12,39t/ha, zatim redukovanom-11,03t/ha i najniži direktnom setvom-10,03t/ha. Konvencionalna obrada obezbedila je najpovoljniju ukupnu poroznost sa prosečnom vrednosti 51,08%. Bez statistički značajne razlike, odnos porozne i čvrste faze je bio nešto nepovoljniji kod zemljišta obrađenog rotositnilicom-50,47zap%, a značajno manji pri direktnoj setvi-48,12zap.%.

The aim of the investigation was to examine the productive characteristics of the most successful and widely used maize hybrids. The paper shows the grain yield of two mid-early maize hybrids: ZP 544 and NS 444 ultra, as well as the yield of six late maturing hybrids: NS640, Zenit, ZP 684, ZP 704, ZP 677 and ZP 735. Both of the mid - early hybrids had a high grain yield. The ZP 544 hybrid achieved the yield of 9,411 t/ha wheareas the NS444 ultra hybrid achieved 9,1 t/ha. Concerning the late maturing hybrids, the highest yield was observed in NS640, Zenit and ZP684 (11,450 t/ ha, 11,196 t/ha and 10,346 t/ha). ZP 704 and ZP 677 had a signitificantly lower yield than the previous three hybrids (9,667 t/ha and 9,488 t/ha). The ZP 735 hybrid gave a yield of 8,190 t/ha which was the lowest yield of all the examined late maturity hybrids. According to the results of the experiment, the best hybrids to be used in the locality of Futog are NS640, Zenit and ZP 684. Cilj rada je da se sagledaju produktivne mogućnosti hibrida iz ogleda na određenom lokalitetu, do sada već dobro poznatih i zapaženih hibrida kukuruza iz šire proizvodnje. Prikazani su rezultati prinosa zrna dva srednje rana hibrida kukuruza: ZP 544, NS 444 ultra, i šest kasnostasnih: NS 640, Zenit, ZP 684, ZP 704, ZP 677, ZP 73. Visoku rodnost u svojstvu prinosa zrna iskazala su oba posmatrana srednje rana hibrida kukuruza. Hibrid ZP 544 ostvario je prosečan prinos suvog zrna 9,411 t/ha, NS 444 ultra 9,100 t/ha. Od kasnostasnih hibrida kukuruza najveću produktivnost u svojstvu prinosa zrna za posmatrani period iskazali su hibridi: NS 640, Zenit i ZP 684. NS 640 je relizovao prosečan prinos od 11,450 t/ha, Zenit 11,19t/ha6, a ZP 684 10,346 t/ha. Hibridi ZP 704 i ZP 677 sa ostvarenim prinosom zrna od 9,667t/ha i 9,488 t/ha, statistički su sa značajno nižom produktivnošću u posmatranom svojstvu od prethodna tri, a hibrid ZP 735 sa prosečnim prinosom zrna od 8,190 t/ha iskazao je visokoznačajno nižu produktvnost od svih kasnostasnih hibrida u ogledu. Prema rezultatima iz ogleda, po visini ostvarenog prinosa zrna stabilna i visoka proizvodnja kukuruza na futoškom ataru bila bi, ako se u sortimentu gajenja nađu hibridi: NS 640, Zenit i ZP 684.

An appropriate choice of the ZP hybrids is a result of studies on yielding carried out under different agroecological conditions. Results on yields of ZP hybrids (FAO 300-700) obtained in production trials in 36 locations carried out in 2006 are presented. The highest yield were detected in the following hybrids ZP 684 and ZP 544, ZP 434 and ZP 341. Furthermore, hybrids ZP 684 and ZP 704 over yielded all hybrids under agroecological conditions of Bačka. In Banat new hybrids ZP 341 and ZP 434 were highly ranked, while the highest yield in Srem were detected in the hybrids ZP 578 and ZP 544, and in the Central Serbia were hybrids ZP 684 and ZP 758. Stated results point out to high yielding and adaptability of hybrids of a new generation (ZP 341, ZP 434, ZP 544, ZP 578, ZP 684, ZP 758). At the same time, high yields of already widely grown old hybrids (ZP 677 and ZP 704) were confirmed. Institut za kukuruz "Zemun Polje" izvodi proizvodne oglede već pet godina, počev od 2002. godine u različitim agroekološkim rejonima Srbije, sa ZP hibridima FAO grupa od 300 do 700. Na osnovu višegodišnjih istraživanja (3-5 godina) može se uraditi potpuno pouzdana rejonizacija i praksi preporučiti najrodniji novi ZP hibridi uz već proverene, rodne hibride stvorene u ranijim ciklusima selekcije. U 2006. godini najviše prosečne prinose u Srbiji ostvarili su : ZP 684 (9,50 t/ha), ZP 544 (9,23 t/ha) i ZP 434 (9,21 t/ha). U regionu Bačke najbolji su bili: ZP 684 (10,43 t/ha), ZP 704 (10,25 t/ha) i ZP 544 (10,06 t/ha), u Banatu ZP 341 (10,02 t/ha), ZP 434 (9,50 t/ha) i ZP 684 (9,44 t/ha) i u Sremu ZP 578 (11,47 t/ha), ZP 544 (11,43 t/ha) i ZP 434 (11,34 t/ha). U Centralnoj Srbiji, dobijeni su niži prinosi, a najrodniji su bili: ZP 684 (8,20 t/ha), ZP 758 (7,63 t/ha) i ZP 544 (7,57 t/ha). ZP hibridi najnovije (V i VI generacije) ispoljili su visoku rodnost i stabilnost prinosa kao i široku prilagodljivost (adaptibilnost) na različite agroekološke uslove gajenja, nivo plodnosti zemljišta i primenu agrotehničkih mera (ZP 341, ZP 434, ZP 544, ZP 578, ZP 684 i ZP 758) i uz već proverene i u širokoj praksi prihvaćene (ZP 677 i ZP 704) hibride predstavljaće najznačajnije ZP hibride u narednim godinama.

Many literature data confirm that fertilizing eliminates, to the largest extent, great differences in natural productivity of various soils. Acid soils are considered one of main yield limiting factors in the plant production and are often studied. Results obtained in stationary trials with the application of different fertilization systems and acid soil improvement measures are used in the present study. According to gained results and conclusions based on them, certain fertilizations systems applied in maize cultivation on acid soils are quite sustainable, especially from the aspect of improvement of such soils and efficiency of applied fertilizers. Pseudogley improvement measures positively affected agrochemical soil properties and resulted in statistically very significant increase of maize yield in all observed locations. The effect of mineral fertilizers on maize yield was greater when they were applied together with improvement measures. At the same time, higher rates of mineral fertilizers did not increase yields in certain locations, due to poor moisture and physical properties of soils that eliminated efficiency of greater fertilizations rates. Veći broj podataka iz literature potvrđuje da se đubrenjem u najvećoj meri eliminišu velike razlike u prirodnim i proizvodnim sposobnostima različitih zemljišta. U biljnoj proizvodnji se vrlo često ističe da je problem kiselîh zemljišta jedan od osnovnih uzroka limitiranih prinosa, vrlo je čest predmet istraživanja. U ovom radu smo koristili rezuitate dobijene izvodenjem stacionarnih ogleda sa primenom različitih sistema đubrenja i mera popravke kiselih zemljišta. Dobijeni rezultati i zaključci koji su na osnovu toga izvedeni, jasno govore o održivosti pojedinih sistema đubrenja pri gajenju kukuruza na kiselim zemljištima, a posebno u pogledu popravke ovoh zemljišta i efikasnosti primenjenih đubriva. Mere popravke pseudogleja pozitivno su uticale na agrohemijske osobine zemljišta i na statistički vrlo značajno povećanje prinosa kukuruza, na svim lokalitetima na kojima su objavljena istraživanja. Efekat mineralnih đubriva na prinos kukuruza bio je veći u interakciji sa merama popravke, pri čemu veća količina mineralnih đubriva na pojedinim lokalitetima nije uticala na povećanje prinosa usled loših vodnofizičkih osobina zemljišta, koje eliminišu efikasnost većih doza đubriva.

The studies were carried out under irrigation conditions in the experimental field of the Maize Research Institute, Zemun Polje, at Zemun Polje during 2002 and 2003. Yields of the total biomass, dry matter and dry grain per area unit were observed in the following early and medium early maturity hybrids: ZP 105, ZP 196, ZP 243, ZP 256, ZP 307 and ZP 360. Hybrids were sown in the last decade of June and yields were observed over the following sowing densities: 65,000, 75,000 and 85,000 plants ha-1. The highest total biomass yields of 28.08 and 34.11 t ha-1, then the highest DM yields of 12.39 and 13.84 t ha-1 and the highest dry grain yields of 6.66, and 7.41 t ha-1 were registered in hybrids ZP 307 and ZP 360, respectively. The higher sowing density was the higher yields of the total biomass (18.83, 20.82 22.69 t ha-1), DM (10.11, 10.95, 11.85 t ha-1) and dry grain (5.81, 6.21 6.69 t ha-1) were. Ispitivanja su obavljena na oglednom dobru Instituta za kukuruz "Zemun Polje" u Zemun Polju 2002. i 2003. godine u uslovima navodnjavanja. Ispitivan je prinos ukupne biomase, suve materije i prinos zrna po jedinici površine kod ranih i srednje ranih hibrida kukuruza: ZP 105, ZP 196, ZP 243, ZP 256, ZP 307 i ZP 360 sejanih u poslednjoj dekadi juna, u zavisnosti od gustina setve (65.000, 75.000, 85.000 bilj/ha) Hibridi ZP 307 i ZP 360 ostvarili su najveću produkciju ukupne biomase (28,08, 34,11 t/ha), najviši prinos suve materije (12,39, 13,84 t/ha) i najviši prinos suvog zrna (6,66, 7,41 t/ha). Sa povećanjem gustine setve povećan je prinos ukupne biomase (18,83, 20,82 22,69 t/ha), suve materije (10,11, 10,95, 11,85 t/ha) i suvog zrna (5,81 6,21, 6,69 t/ha).

The study presents effects of seven sowing densities (G1 - 40,816, G2 50,125, G3 - 59,523, G4 - 69,686, G5 - 79,365, G6 - 89,286 and G7 - 98,522 plants ha-1) on grain yield of six ZP maize hybrids (ZP 360, ZP 539, ZP 580 ZP 680, ZP 677, ZP 704). The trial was performed on chernozem in experimental fields of the Maize Research Institute, Zemun Polje in the period 1998-2000. A 4-replicate three-year two-factorial trial was set up according to the split-plot method under rainfed conditions. Obtained results indicate to statistically very significant differences in grain yields over investigation years and among maize hybrids. The lowest average yield (6.05 t ha-1), with statistically very significant differences in relation to other two years (1988 - 11.52 t ha-1, 1999 - 11.35 t ha-1) was achieved in the year with the smallest amount of precipitation during the growing season (2000). The highest yields were obtained at different densities in dependence on weather conditions during the growing season and maize hybrids. In relatively favorable years the highest yields of the studied hybrids were obtained in the following densities: ZP 360 - 80-90,000 plants ha-1; ZP 539 -80.000 plants ha-1; ZP 580 - 70-80,000 plants ha-1; ZP 633 - 70,000 plants ha-1; ZP 677 - 60-70,000 plants ha-1; ZP 704 70-80,000 plants ha-1. The following densities were the most favorable under conditions of pronounced water deficit during the growing period: ZP 360 - 70,000 plants ha-1; ZP 539 - 60-70,000 plants ha-1; ZP 580 - 50-60,000 plants ha-1; ZP 633 - 70,000 plants ha-1; ZP 677 - 50-60,000 plants ha-1; ZP 704 - 60-70,000 plants ha-1. U radu su prikazani rezultati proučavanja uticaja sedam gustina setve ( G1 40.816 bilj/ha, G2 -50.125 bilj/ha, G3 - 59.523 bilj/ha, G4 - 69.686 bilj/ha, G5 -79.365 bilj/ha, G6 - 89.286 bilj/ha, G7 - 98.522 bilj/ha) na prinos zrna šest ZP hibrida kukuruza (ZP 360, ZP 539, ZP 580, ZP 680, ZP 677, ZP 704). Trogodišnja ispitivanja (1998-2000) obavljena su u agroekološkim uslovima Zemun Polja u prirodnom vodnom režimu. Dobijeni rezultati pokazuju da su, u godinama proučavanja, između ispitivanih hibrida i gustina ostvarene statistički veoma značajne razlike prinosa zrna kukuruza. U godini sa najmanje padavina tokom vegetacije (2000), ostvareni su najniži prosečni prinosi (6,05 t/ha), sa statistički veoma značajnom razlikom u odnosu na druge dve godine (1988. - 11,52 t/ha, 1999. - 11,35 t/ha). U zavisnosti od meteoroloških uslova tokom vegetacije najviši prinosi ostvareni su različitim gustinama setve. U relativno povoljnijim godinama za gajenje kukuruza ispitivani hibridi ostvarili su najbolje rezultate prinosa u sledećim gustinama: ZP 360 - 80-90.000 bilj/ha, ZP 539 - 80.000 bilj/ha ZP 580 -70-80.000 bilj/ha, ZP 633 -70.000 bilj/ha, ZP 677 - 60-70.000 bilj/ha, ZP 704 - 70-80.000 bilj/ha. U uslovima izrazitog deficita vode tokom vegetacije najpovoljnije gustine su: ZP 360 -70.000 bilj/ha, ZP 539 60-70.000 bilj/ha, ZP 580 - 50-60.000 bilj/ha, ZP 633 - 70.000 bilj/ha, ZP 677 -50-60.000 bilj/ha, ZP 704 - 60-70.000 bilj/ha.

According to Long term experiments on chernozem and pseudoglay with different fertilizing systems could be conclused: According to performed experiments certain systems of maize crop rotation significantly affected maize yield (8,51% to 19,41%), and also resulted in similar or higher yields with the application of lesser amounts of nitrogen (50%) of maize was grown in crop rotation with soybean. Soil organic matter content was significantly increased (10,76% to 27,7%) due to the application of organic fertilizers to chernozem. The effects of particular fertilizing systems with mineral and organic manure on maize yield increase (8,16% to 71,65%) were statistically significant. Furthermore, systems with organic fertilizer and lower amounts of nitrogen (46 kg ha-1) were especially economically justified. Stover ploughing positively affected yield increase in all fertilizing systems. Measures of soil amendment (CaO, "njival" liquid and stable manure) significantly influenced improvement of adverse agrochemical properties of pseudogley (pH, easy mobile Al, etc) and alongside with mineral nutrition significantly affected maize yield increase. The studies point out that the application of nitrogen fertilizers in the stationary trial resulted in significant increase of available nitrogen content and its accumulation over the whole depth of the soil profile of chernozem type of soil. This was especially expressed with the application of higher ratios of nitrogen fertilizers and the increases were statistically very significant. The long-term application of higher ratios of nitrogen fertilizer (270 kgN ha-1) leads to excessive accumulation of available nitrogen not only in surface but also in deeper layers of this soil, and therefore the risk from pollution by nitrates not only of plant products but of underground water increases and the outcome of it is economic loss. Based on the analyses of samples collected in four locations with similar soils under maize and the application of medium high ratios of nitrogen fertilizers (135 kgN ha-1) it is noticeable that available nitrogen content significantly varied over locations in relation to its distribution and its total content in the soil profile to the depth of up to 200 cm. Increased available nitrogen content in deeper layers and higher risk from underground. Na osnovu rezultata dugotrajnih stacionarnih ogleda obavljena su istraživanja održivosti pojedinih sistema đubrenja u proizvodnji kukuruza. Ogledi su izvođeni na zemunpoljskom černozemu i na kiselim zemljištima (pseudoglej i smeđe rudo kiselo zemljište), i na osnovu dobivenih rezultata mogu se izvući sledeći zaključci: - pri gajenju u monokulturi na černozemu dugotrajna primena različitih sistema đubrenja organskim (stajnjak i kukuruzovina) i mineralnim đubrivima vrlo značajno je uticala na promene sadržaja organske materije zemljišta pri čemu je povećanje sadržaja pod uticajem zaoravanja kukuruzovine i stajnjaka iznosilo 10,76% do 17,73%, pri čemu je došlo i do značajnog povećanja odnosa C/N. - mere popravke pseudogleja pozitivno su uticale na agrohemijske osobine zemljišta (povećanje pH vrednosti, povećanje zasićenosti bazama, kao i na značajno smanjenje sadržaja lakopristupačnog aluminijuma) - merama popravke pseudogleja statistički je vrlo značajno povećan prinos kukuruza na svim lokalitetima istraživanja, a efekat mineralnih đubriva na prinos kukuruza bio je veći u interakciji sa merama popravke. Veća količina mineralnih đubriva nije uticala na povećanje prinosa (Kraljevo), što se može objasniti lošim vodnofizičkim osobinama pseudogleja kao ograničavajućim faktorom. pojedini sistemi đubrenja mineralnim i organskim đubrivima vrlo značajno su uticali na povećanje prinosa (8,16% do 71,65%), pri čemu su posebno ekonomski opravdani sistemi sa organskim đubrivima i manjim količinama azota (46 kg ha-1). Zaoravanje kukuruzovine je vrlo povoljno uticalo na povećanje prinosa (6,89%) u odnosu na iste sisteme bez kukuruzovine. Efikasnost primenjenog stajnjaka je iznosilo nešto iznad 50% efikasnosti mineralnih đubriva, a pri zajedničkoj primeni sa kukuruzovinom, njegova efikasnost je vrlo značajno povećana, i tako se na černozemu prinos može održavati na visokom nivou i bez primene mineralnih đubriva. Rezultati istraživanja su pokazali da su pojedini plodoredi na černozemu vrlo značajno uticali na povećanje prinosa kukuruza (8,51% do 19,42%), a pri tome je značajno povećana efikasnost primenjenih mineralnih đubriva, posebno ukoliko je kukuruz gajen u plodoredu sa sojom (dvopolje) i pšenicom i sojom (tropolje). Primena visokih doza azota u vidu mineralnih đubriva kao i akumulacija vode u mikrodepresijama na propusnim zemljištima, značajno su uticali na ispiranje i akumulaciju pristupačnog azota po celom zemljišnom profilu što može uticati na zagađivanje podzemnih voda.

Maize hybrid yield is to the greatest extent affected by agroecological conditions and growing technology. The more suitable the maize growing technology, the higher the yield and then the crop can be planted over greater areas. Therefore, the aim of this study was to test ZP hybrids of various maturity groups and find out the top yielding hybrid under different agroecological conditions and identical growing technology, especially the hybrid with the most stable yield. The following maize hybrids were studied ZP 360, ZP 434, ZP 480, ZP 488 (FAO 300-400); ZP 570, ZP 580, ZP 599 (FAO 500); ZP 677, ZP 680 (FAO 600) in six locations (Kanjiža, Sombor, Zemun Polje - dry land farming, Zemun Polje - irrigation, Šabac and Leskovac). The results of the two-year investigation point to greater or smaller variation of yields of the investigated ZP maize hybrids under different agroecological conditions. The hybrids ZP 434, ZP 360 and ZP 677 expressed good general adaptability and stability.