Selection of Materials for the Protection of the Hoe Blades of the Inter-Row Cultivator

The paper presents the results of comparative wearing of cultivator hoes protected with two different materials with regard to the lifespan of the blades. During the operation of the hoes outside the track of the tractor wheels with protected blades of materials M1 and M2, equal wear of mass and surface was recorded. The hoes lost an average of 0,563 g/ha cultivated area or an average of 119,46 g with a standard deviation of 2,876 when working with both blades in compacted soil (in the tracks of tractor wheels) protected by M1 material. For hoes protected by M2 material, the average loss was 0,566 g/ha of cultivated area or an average of 120,10 g for the research period with a standard deviation of 4,609. Both materials in the most difficult working conditions showed equal resistance to wear and retention of the initial shape of the hoe

Influence of Rotational Speed of Seed Plates on the Quality Seeding in Laboratory Operating Conditions

The simulation results of sunflower seeding in the laboratory with seed plates from 12 to 36 holes at working speeds from 4 to 10 km/h are presented. At a working speed of 6 km/h, the seed plate n = 12 with a rotational speed of 0.652 m/s achieved an average seeding spacing of 23.26 cm. At this rotational speed, the plate achieved a QFI of 89.15. The seed plate n = 36 with a rotational speed of 0.217 m/s achieved an average spacing of 21.76 cm with a QFI index of 98.45. At a working speed of 10 km/h, the seeding machine achieved an average spacing of 23.87 cm with a seed plate n = 12. The same seed plate achieved a rotational speed of 1.812 m/s. The seed plate n = 36 with a rotational speed of 0.602 m/s recorded an average spacing in the seeding simulation of 22.52 cm

PESTICIDE APPLICATION TECHNICS IMPROVEMENT

Sveučilišni udžbenik Unapređenje tehnike aplikacije pesticida plod je višegodišnjega teorijskoga modeliranja, praktičnoga ispitivanja i sakupljanja podataka koji se odnose na tehničke sustave u zaštiti bilja i njeno okruženje u užem smislu. U ovome prvome izdanju uglavnom su obuhvaćena područja kojima se autori bave više godina. Cilj autora je potpun i jasan prikaz metodologije rješavanja konkretnih problema u upravljanju poljoprivrednom tehnikom u zaštiti bilja, izravno primjenjivih u praksi - “Know-How”, sa što je god moguće više upotrebljivih podataka. Izvori su, uz domaće, uglavnom američki i zapadnoeuropski. Knjiga je namijenjena svima onima koji se već služe poljoprivrednom tehnikom u zaštiti bilja i onima koji tek svladavaju osnove pravilne primjene tehničkih sustava u svakodnevnoj praksi, bez obzira na veličinu poljoprivrednoga gospodarstva. Neke osnove fizičke logike, analize i sinteze pojedinih zakonitosti pri uporabi i pesticida i tehničkih sustava detaljno smo obradili i pojasnili, zbog velike važnosti razumijevanja problematike.The academic textbook Pesticide application tehnics improvement is the result of several-year recording theoretical models, numerous practical tests, and data collection relating to technical systems in plant protection and its environment in the narrowest sense. In this first edition, the authors cover the area they have dealt with for many years. The authors aimed to present complete and clear methods how to solve specific problems in the agricultural practice management, plant protection, and direct practice application – ‘‘Know- How\u27\u27, with as many as possible useful data. References used, along with local ones, are mostly American and from Western Europe. This textbook is intended for those who already use the agricultural technique in plant protection and those who are just acquiring the basics of technical systems proper application in daily practice, regardless the size of the agricultural farm. The authors covered in details and explained some bases of physics logic, analysis, and synthesis of specific laws while using pesticides due to extremely importance in understanding the problem area

The Impact of Conventional and Sensor Spraying on Drift and Deposit in Cherry Orchard

The research results of the spraying technical factors\u27 impact on ground and air drift, and the deposit on the treetop in cherry orchards, are presented in the paper. Two different spraying systems (classical and sensory system) are investigated, Agromehanika AGP 200 ENU sprayer being used. The research is conducted according to ISO standard 22866 (Plant Protection Equipment - Drift Measurement Methods in Field Conditions). The impact of spraying norm as factor A (A1 – 250 l/ha; A2 – 200 l/ha); the nozzle type as factor B (B1 – Lechler TR 8002 C; B2 – Lechler ITR 8002 C) and the fan air velocity as factor C (C1 – 18 m/s; C2 – 12 m/s) are examined by the variance analysis. To spray and evaluate the drift, Tartazine organic dye solution with 4% concentration is used. The filter papers, used as collectors, according to the specified ISO standard, are placed directly in the spraying zone. The sampled filter papers are washed out with 10 ml of deionised water under laboratory conditions. After washing, the colour intensity, i.e., the solution wave-length, is read by a spectrophotometer (Varian Cary 50 UV-Visible). Different drift intensity (ground and air drift) and treetop deposits are realized by the usage of various treatments of technical spraying factors and various spraying systems. Unlike the ground and air drifts, the deposit within the treetop does not show statistically significant change by using a sensory spraying system, i.e. by using a selective application

PESTICIDE APPLICATION TECHNICS IMPROVEMENT

Sveučilišni udžbenik Unapređenje tehnike aplikacije pesticida plod je višegodišnjega teorijskoga modeliranja, praktičnoga ispitivanja i sakupljanja podataka koji se odnose na tehničke sustave u zaštiti bilja i njeno okruženje u užem smislu. U ovome prvome izdanju uglavnom su obuhvaćena područja kojima se autori bave više godina. Cilj autora je potpun i jasan prikaz metodologije rješavanja konkretnih problema u upravljanju poljoprivrednom tehnikom u zaštiti bilja, izravno primjenjivih u praksi - “Know-How”, sa što je god moguće više upotrebljivih podataka. Izvori su, uz domaće, uglavnom američki i zapadnoeuropski. Knjiga je namijenjena svima onima koji se već služe poljoprivrednom tehnikom u zaštiti bilja i onima koji tek svladavaju osnove pravilne primjene tehničkih sustava u svakodnevnoj praksi, bez obzira na veličinu poljoprivrednoga gospodarstva. Neke osnove fizičke logike, analize i sinteze pojedinih zakonitosti pri uporabi i pesticida i tehničkih sustava detaljno smo obradili i pojasnili, zbog velike važnosti razumijevanja problematike.The academic textbook Pesticide application tehnics improvement is the result of several-year recording theoretical models, numerous practical tests, and data collection relating to technical systems in plant protection and its environment in the narrowest sense. In this first edition, the authors cover the area they have dealt with for many years. The authors aimed to present complete and clear methods how to solve specific problems in the agricultural practice management, plant protection, and direct practice application – ‘‘Know- How\u27\u27, with as many as possible useful data. References used, along with local ones, are mostly American and from Western Europe. This textbook is intended for those who already use the agricultural technique in plant protection and those who are just acquiring the basics of technical systems proper application in daily practice, regardless the size of the agricultural farm. The authors covered in details and explained some bases of physics logic, analysis, and synthesis of specific laws while using pesticides due to extremely importance in understanding the problem area

UPOTREBA VODOOSJETLJIVIH PAPIRIĆA ZA PROCJENU POKRIVENOSTI LISNE POVRŠINE U VOĆNJAKU JABUKE

Three commercial mist-blowers were tested in an apple orchard at the end of vegetation development in October 2008, using pure water and water sensitive papers (WSP). The width between apples rows was 3.5 m, the average width of tree top was 1.6 m and the average apple height was 3.6 m. All the machines had the same “Albuz ATR 80” red nozzles and the tractor’s PTO had a rotational speed of 540 rpm. The average temperature during testing was 17.05 °C; the average air humidity was 56.55 %, and the average wind speed was 0.9 m/s from the West. The spraying equipment used was: (A) “Tifone Vento” 1500, water levels of 1000 l/ha, maximum. air velocity of 30 m/s and 18638 m3/h of airflow, 14 nozzles, travel velocity of 5 km/h and work pressure of 17 bars; (B) “Myers N1500”, water level of 1000 l/ha, maximum. air velocity of 34 m/s and 36580 m3/h of airflow, 14 nozzles, travel velocity of 5 km/h and work pressure bar of 11 bar; (C) “Hardi Zaturn 1500”, water level of 1000 l/ha, maximum. Air velocity of 38 m/s and 44590 m3/h of airflow, 18 nozzles, travel velocity of 5 km/h and work pressure of 7 bar. The “Tifone” mistblower had 10048 m3/h total amount of air on the left side of the blower and 8590 m3/h on the right side. With this amount of air, the average WSP coverage on the left side was 44.05 %, and on the right was 41.33 %. The“Myers” mistblower had 18120 m3/h total amount of air on the left side of the blower and 18460 m3/h at the right side. With this amount of air, the average WSP coverage on the left side was 33.61 %, and on the right side was 37.98 %. (C) The “Hardi” mistblower had 24940 m3/h total amount of air on the left side of the blower and 19650 m3/h on the right side. With this amount of air, the average WSP coverage on the left side was 45.85 %, and on the right side was 42.47 %. The WSP were photographed by a “Canon EOS 1000D”. The pictures were then converted by “Irfan View 4.0”, and finally elaborated by “Adobe Photoshop”, “Global Lab Image/2” and “Graduate” softwares.U radu su prikazani rezultati istraživanja tri raspršivača pri radu u voćnjaku jabuke tijekom listopada 2008. Prilikom usporedbe korištena je čista voda uz primjenu metode vodoosjetljivih papirića (VOP). Širina redova u nasadu iznosila je 3,5 m, uz prosječnu širinu krošnje od 1,6 m, i visinu stabla od 3,6 m. Ispitivani raspršivači bili su opremljeni mlaznicama „Albuz ATR 80“(crvene boje), a sva ispitivanja obavljena su pri 540 min-1 priključnoga vratila traktora. Prosječna temperatura zraka u vremenskom intervalu ispitivanja iznosila je 17,05°C, s prosječnom vrijednosti vlažnosti zraka 56,50%. Prosječna brzina vjetra iznosila je 0,90 m/s u smjeru rada raspršivača. Testirani raspršivači bili su „Tifone Vento“, „Myers N1500“ i „Hardi Zaturn“. „Tifone Vento“ imao je sljedeće parametre rada: hektarsku dozu vode od 1000 l, maksimalnu brzinu zraka od 30 m/s i ukupnu količinu zraka od 18 638 m3/h, 14 mlaznica, radnu brzinu od 5 km/h i radni tlak od 17 bar. „Myers N1500“ imao je sljedeće parametre rada: hektarsku dozu vode od 1000 l, maksimalnu brzinu zraka od 34 m/s i ukupnu količinu zraka od 36580 m3/h, 14 mlaznica, brzinu kretanja od 5 km/h i radni tlak od 11 bara, dok je „Hardi Zaturn“ imao hektarsku dozu vode od 1000 l, maksimalnu brzinu zraka od 38 m/s i ukupnu količinu zraka od 44590 m3/h, 18 mlaznica, brzinu kretanja od 5 km/h i radni tlak od 7 bara. Raspršivač „Tifone“ na lijevoj strani stroja imao je prosječnu količinu zraka od 10048 m3/h te je ostvario prosječnu pokrivenost na VOP-u od 44,05 %. Na desnoj strani stroja utvrđena je prosječna količina zraka od 8590 m3/h i prosječna pokrivenost na VOP-u od 41.33 %. Raspršivač „Myers“ na lijevoj strani stroja imao je prosječnu količinu zraka od 18120 m3/h te je ostvario prosječnu pokrivenost na VOP-u od 33.61%. Na desnoj strani stroja utvrđena je prosječna količina zraka od 18460 m3/h i prosječna pokrivenost na VOP-u od 37.98% Kod raspršivača „Hardi“ utvrđena je prosječna količina zraka na lijevoj strani od 24940 m3/h te je postigao prosječnu pokrivenost na VOP-u od 45.85 %. Na desnoj strani stroja utvrđena je prosječna količina zraka od 19650 m3/h i ostvarena je prosječna pokrivenost od 42,47 % na postavljenim VOP-ima. Prilikom istraživanja korištena je metodika, pri čemu su VOP fotografirani, a slike su konvertirane softverom “Irfan View 4.0” te kasnije obrađivane “Adobe Photoshopom”, “Global Lab Image/2” i “Graduate” softverom

Utjecaj sklopa i načina sjetve na prinos zrna kukuruza

U radu su prikazani rezultati ostvarenog prinosa zrna kukuruza pri različitim sustavima sjetve u 2016. godini na pokušalištu Slovinska Kovačica (45°45ʹ44,85ʺ N i 17°0ʹ21,43ʺ E). Sjetva je obavljena u udvojene redove s razmakom od 22 cm (twin row tehnologija) i na standardni način s razmakom redova od 70 cm. Korištena su dva hibrida kukuruza P0023 (FAO 420) i P0412 (FAO 520) posijana u četiri različita sklopa. Analizom varijance utvrđeno je da su sustav sjetve i sklop statistički značajno utjecali na ostvareni prinos zrna (kg ha-1). U standardnoj sjetvi hibrid P0023 u prosječnom sklopu od 64 116 biljaka ha-1 ostvario je prinos zrna od 13 374 kg ha-1, a u sjetvi udvojenih redova zabilježen je prinos zrna veći za 5,12%. Najveći prinos istog hibrida u standardnoj sjetvi ostvaren je pri sklopu od 94 466 biljaka ha-1 (14 264 kg ha-1), dok je u udvojenim redovima ostvaren prinos od 15 004 kg ha-1 ili 5,19 % više. Povećanjem prosječnog sklopa na 103 741 i 104 931 biljaka ha-1 u oba sustava sjetve došlo je do pada prinosa zrna na 13 237 i 14 143 kg ha-1, pri čemu je ipak sjetva u udvojene redove i u ovim uvjetima rezultirala povećanjem prinosa od 6,84%. Hibrid P0412 u sklopu od 95 935 biljaka ha-1 u udvojenim redovima ostvario je prinos zrna od 14 994 kg ha-1 ili 5,82 % više dok je u sklopu od 105 143 biljaka ha-1 u sjetvi u udvojene redove zabilježen također viši prinos zrna za 4,56%. Najbolji rezultat u pokusu hibrida P0023 ostvaren je sjetvom u udvojene redove u sklopu 95 389 biljaka ha-1, a hibrida P0412 također sjetvom u udvojene redove u sklopu 76 133 biljaka ha-1. U sustavu sjetve u udvojene redove utvrđena je nešto niža vlaga zrna u vrijeme berbe kod oba hibrida.The paper presents the results of the achieved corn grain yield under different sowing systems in 2016. at the Slovinska Kovačica experimental field (45°45ʹ44.85ʺ N; 17°0ʹ21.43ʺ E). Sowing was done in double rows with a spacing of 22 cm (twin row technology) and in the standard way with a row spacing of 70 cm. Two maize hybrids, P0023 (FAO 420) and P0412 (FAO 520) sown in four different set of plants, were used. Analysis of variance showed that the sowing system and set of plants had a statistically significant effect on the achieved grain yield (kg ha-1). In standard sowing, the hybrid P0023 in an average of 64 116 plants ha-1 achieved a grain yield of 13 374 kg ha-1, and in the sowing in twin rows, the grain yield was increased by 5,12 %. The highest yield of the same hybrid in standard sowing was achieved with 94 466 ha-1 plants (14 264 kg ha-1), while in twin row the yield was 15 004 kg ha-1 or 5,19 % higher. Increasing the average set to 103 741 and 104 931 ha-1 plants in both sowing systems led to a decrease in grain yield to 13 237 and 14 143 kg ha-1, while sowing in double rows and in these conditions resulted in an increase in yield of 6,84 %. Hybrid P0412 with 95 935 plants ha-1 in twin row achieved a grain yield of 14 994 kg ha-1 or 5,82 % more, while with 105 143 ha-1 plants in twin rows higher yield was also recorded by 4,56 %. The best result in the experiment with hybrid P0023 was achieved by sowing in twin rows with 95 389 plants ha-1 and hybrid P0412 also by sowing in twin rows with 76 133 ha-1 plants. In the twin row sowing system, slightly lower grain moisture was found at harvest time in both hybrids

UPOTREBA VODOOSJETLJIVIH PAPIRIĆA ZA PROCJENU POKRIVENOSTI LISNE POVRŠINE U VOĆNJAKU JABUKE

Three commercial mist-blowers were tested in an apple orchard at the end of vegetation development in October 2008, using pure water and water sensitive papers (WSP). The width between apples rows was 3.5 m, the average width of tree top was 1.6 m and the average apple height was 3.6 m. All the machines had the same “Albuz ATR 80” red nozzles and the tractor’s PTO had a rotational speed of 540 rpm. The average temperature during testing was 17.05 °C; the average air humidity was 56.55 %, and the average wind speed was 0.9 m/s from the West. The spraying equipment used was: (A) “Tifone Vento” 1500, water levels of 1000 l/ha, maximum. air velocity of 30 m/s and 18638 m3/h of airflow, 14 nozzles, travel velocity of 5 km/h and work pressure of 17 bars; (B) “Myers N1500”, water level of 1000 l/ha, maximum. air velocity of 34 m/s and 36580 m3/h of airflow, 14 nozzles, travel velocity of 5 km/h and work pressure bar of 11 bar; (C) “Hardi Zaturn 1500”, water level of 1000 l/ha, maximum. Air velocity of 38 m/s and 44590 m3/h of airflow, 18 nozzles, travel velocity of 5 km/h and work pressure of 7 bar. The “Tifone” mistblower had 10048 m3/h total amount of air on the left side of the blower and 8590 m3/h on the right side. With this amount of air, the average WSP coverage on the left side was 44.05 %, and on the right was 41.33 %. The“Myers” mistblower had 18120 m3/h total amount of air on the left side of the blower and 18460 m3/h at the right side. With this amount of air, the average WSP coverage on the left side was 33.61 %, and on the right side was 37.98 %. (C) The “Hardi” mistblower had 24940 m3/h total amount of air on the left side of the blower and 19650 m3/h on the right side. With this amount of air, the average WSP coverage on the left side was 45.85 %, and on the right side was 42.47 %. The WSP were photographed by a “Canon EOS 1000D”. The pictures were then converted by “Irfan View 4.0”, and finally elaborated by “Adobe Photoshop”, “Global Lab Image/2” and “Graduate” softwares.U radu su prikazani rezultati istraživanja tri raspršivača pri radu u voćnjaku jabuke tijekom listopada 2008. Prilikom usporedbe korištena je čista voda uz primjenu metode vodoosjetljivih papirića (VOP). Širina redova u nasadu iznosila je 3,5 m, uz prosječnu širinu krošnje od 1,6 m, i visinu stabla od 3,6 m. Ispitivani raspršivači bili su opremljeni mlaznicama „Albuz ATR 80“(crvene boje), a sva ispitivanja obavljena su pri 540 min-1 priključnoga vratila traktora. Prosječna temperatura zraka u vremenskom intervalu ispitivanja iznosila je 17,05°C, s prosječnom vrijednosti vlažnosti zraka 56,50%. Prosječna brzina vjetra iznosila je 0,90 m/s u smjeru rada raspršivača. Testirani raspršivači bili su „Tifone Vento“, „Myers N1500“ i „Hardi Zaturn“. „Tifone Vento“ imao je sljedeće parametre rada: hektarsku dozu vode od 1000 l, maksimalnu brzinu zraka od 30 m/s i ukupnu količinu zraka od 18 638 m3/h, 14 mlaznica, radnu brzinu od 5 km/h i radni tlak od 17 bar. „Myers N1500“ imao je sljedeće parametre rada: hektarsku dozu vode od 1000 l, maksimalnu brzinu zraka od 34 m/s i ukupnu količinu zraka od 36580 m3/h, 14 mlaznica, brzinu kretanja od 5 km/h i radni tlak od 11 bara, dok je „Hardi Zaturn“ imao hektarsku dozu vode od 1000 l, maksimalnu brzinu zraka od 38 m/s i ukupnu količinu zraka od 44590 m3/h, 18 mlaznica, brzinu kretanja od 5 km/h i radni tlak od 7 bara. Raspršivač „Tifone“ na lijevoj strani stroja imao je prosječnu količinu zraka od 10048 m3/h te je ostvario prosječnu pokrivenost na VOP-u od 44,05 %. Na desnoj strani stroja utvrđena je prosječna količina zraka od 8590 m3/h i prosječna pokrivenost na VOP-u od 41.33 %. Raspršivač „Myers“ na lijevoj strani stroja imao je prosječnu količinu zraka od 18120 m3/h te je ostvario prosječnu pokrivenost na VOP-u od 33.61%. Na desnoj strani stroja utvrđena je prosječna količina zraka od 18460 m3/h i prosječna pokrivenost na VOP-u od 37.98% Kod raspršivača „Hardi“ utvrđena je prosječna količina zraka na lijevoj strani od 24940 m3/h te je postigao prosječnu pokrivenost na VOP-u od 45.85 %. Na desnoj strani stroja utvrđena je prosječna količina zraka od 19650 m3/h i ostvarena je prosječna pokrivenost od 42,47 % na postavljenim VOP-ima. Prilikom istraživanja korištena je metodika, pri čemu su VOP fotografirani, a slike su konvertirane softverom “Irfan View 4.0” te kasnije obrađivane “Adobe Photoshopom”, “Global Lab Image/2” i “Graduate” softverom

Impact of sowing system in the five-year period on maize grain yield

U radu su prikazani rezultati utjecaja standardne sjetve i sjetve u udvojene redove tj. twin row tehnologije na prinos zrna kukuruza u Republici Hrvatskoj. Istraživanja su provedena od 2016. do 2020. godine na dva pokušališta: Jakšić (45°21\u2756,12"N i 17°47\u270,08"E) i pokušalište Lužani (45°09\u2707,8"N i 17°42\u2741,6"E). U istraživanju je provedena sjetva hibrida KWS 2370 (FAO 290) i KWS Smaragd (FAO 350) na razmak redova 70 cm, te u udvojene redove s razmakom 22 cm. Tijekom provođenja pokusa sjetvom u udvojene redove ostvaren je značajno veći prinos zrna (kg ha-1), ali s nešto većom vlagom zrna u vrijeme berbe. Najviši prinos zrna na pokušalištu Jakšić u standardnoj sjetvi zabilježen je 2016. godine od 12 180 kg ha-1 kod hibrida KWS 2370 iz FAO grupe 290 dok je u sjetvi u sustavu udvojenih redova ostvaren prosječni prinos zrna veći za 10,76 % u odnosu na standardnu sjetvu. Najniži zabilježeni prinosi zrna (kg ha-1) na istom pokušalištu ostvaren je u 2017. vegetacijskoj godini. Iste godine u tehnologiji udvojenih redova ostvaren je prinos zrna za 15,51 % veći u odnosu na standardnu sjetvu. Također u vegetacijskoj 2017. godini i na pokušalištu Lužani zabilježeni su najniži prosječni prinosi zrna u berbi pri čemu je sjetva u udvojene redove ostvarila povećanje prinosa od 12,03 % u odnosu na standardnu sjetvu. Kod sjetve hibrida KWS Smaragd najniži prinos zrna zabilježen je u 2016. godini s 10 450 kg ha-1, dok je prinos u udvojenim redovima iznosio 11 693 kg ha-1, pri čemu je zabilježena i najveća razlika između sustava sjetve od 11,89 % na pokušalištu Lužani. Sjetva u udvojene redove na oba pokušališta rezultirala je statistički značajnim razlikama za glavna svojstva istraživanja u svih pet vegetacijskih godina. Statistički značajne razlike uočene su i za svojstvo mase zrna po klipu kao i sadržaja vlage u zrnu. Nešto niža vrijednost vlage u zrnu u svih pet godina istraživanja zabilježena je u standardnoj sjetvi. Razlike ostvarenih sklopova na pokušalištima u vrijeme petogodišnjeg istraživanja nisu bile statistički značajne.The paper presents the results of the influence of standard and sowing in double rows, ie twin row technology on corn grain yield in the Republic of Croatia. The research was conducted from 2016. to 2020. at two experimental field Jakšić (45°21\u2756,12"N and 17°47\u270,08"E) and experimental field Lužani (45°09\u2707,8"N and 17°42\u2741,6 "E). The research was carried out by sowing hybrids KWS 2370 (FAO 290) and KWS Smaragd (FAO 350) in the standard way with a row spacing of 70 cm, and in double rows with a spacing of 22 cm. During the experiment by sowing in twin rows, a significantly higher grain yield of kg ha-1 was achieved, but with slightly higher grain moisture at harvest time. The highest yield at the experimental field Jakšić in standard sowing was recorded in 2016 of 12 180 kg ha-1 in hybrid KWS 2370 from FAO group 290 while in twin row sowing the average grain yield was higher by 10.76 % compared to standard sowing. The lowest recorded grain yield kg ha-1 at the same experimental field was achieved in the 2017 vegetation year. In the same year, in the twin row sowing, the grain yield was 15.51 % higher than in standard sowing. Also, in the vegetation year 2017 at the Lužani experimental field, the lowest average grain yield in the harvest was recorded, while sowing in twin rows achieved a yield increase of 12.03 % compared to standard sowing. When sowing KWS Smaragd hybrid, the lowest grain yield was recorded in 2016 with 10 450 kg ha-1, while the yield in twin rows was 11 693 kg ha-1 with the largest difference between the sowing systems of 11,89 % in the experimental field Lužani. Sowing in twin rows at both experimental sites resulted in statistically significant differences for the main study properties in all five vegetation years. Statistically significant differences were observed for the property of grain mass per cob as well as for the moisture content in the grain. A slightly lower value of grain moisture in all five years of research was recorded in standard sowing. The differences in the realized set of plants at the experimental field sites at the time of the five-year study were not statistically significant

Utjecaj frakcija zrna kukuruza i tehničkih čimbenika podešavanja na kvalitetu rada sijaćice PSK4

U radu su prikazani rezultati kvalitete sjetve pri simulaciji na ispitnome stolu. Utvrđivanje kvalitete rada sijaćice prikazano je s pomoću koeficijenata kvalitete sjetve (ISO standard 7256/1 i 7256/2), odnosno MISS, MULT i QFI indeksa. Ispitan je utjecaj četiriju različitih frakcija sjemena kukuruza dvaju hibrida na kvalitetu sjetve. Simulacija sjetve obavljena je s različitim tehničkim čimbenicima podešavanja sijaćice na ispitnome stolu (dva podtlaka, tri radne brzine sijaćice i četiri položaja skidača viška sjemena). Provedenom simulacijom sjetve utvrđena je statistički značajna razlika utjecaja različitih oblika/frakcija zrna, položaja skidača sjemena, podtlaka i radne brzine sijaćice na razmak zrna unutar reda prilikom sjetve oba istraživana hibrida. Podtlačna sijaćica PSK4 ostvarila je na ispitnome stolu pri radnoj brzini od 4 km ha-1 i položaju skidača sjemena na oznaci 10 visoke koeficijente kvalitete sjetve te se temeljem ostvarenoga QFI indeksa >98,6% može svrstati u grupu vrlo dobrih sijaćica. Nadalje, pri upotrebi hibrida H1 ostvaren je prosječni razmaka zrna u sjetvi unutar reda od 19,60 cm, koji osigurava sjetvu od 72.448 biljaka ha-1, dok je sjetvom hibrida H2 ostvaren prosječni razmak sjetve od 19,51 cm (72.831 biljaka ha-1). LSD0,05 testom utvrđena je statistički značajna razlika razmaka zrna unutar reda između navedenih hibrida