Impact of technical spraying factors on leaf area coverage in an apple orchard

Abstract

Istraživanja su obavljena u nasadu jabuke sa dva tipa raspršivača, aksijalni (Hardi Zaturn) i radijalni (Hardi Arrow). Istraživan je utjecaj glavnih tehničkih čimbenika raspršivanja (tip mlaznice, brzina rada i norma raspršivanja) na pokrivenost tretirane površine, prosječni promjer kapljica, broj kapljica/cm2 i zanošenje tekućine. Brzina rada raspršivača podešava se na 6 i 8 k/mh, a norma raspršivanja na 250, 325 i 400 l/ha. Koriste se plave (TR 8003C), žute (TR 8002C) i zelene (TR 80015C) Lechler mlaznice. Istraživanje se postavlja kao trofaktorijalni poljski pokus sa 18 tretmana u 4 ponavljanja, za svaki tip raspršivača. Po tretmanu se na stablo postavlja 60 vodoosjetljivih papirića koji se obrađuju pomoću računalne analize slike i računalnog programa ImageJ. Glavni tehnički čimbenici raspršivanja ostvaruju statistički vrlo značajan utjecaj (**) na glavna svojstva istraživanja. Smanjivanjem ISO broja mlaznice, povećanjem brzine rada raspršivača te povećanjem norme raspršivanja povećava se pokrivenost tretirane površine, broj kapljica/cm2 i zanošenje tekućine, a smanjuje se prosječni promjer kapljica. Usporedbom dobivenih rezultata istraživanja sa aksijalnim i radijalnim raspršivačem u nasadu jabuke, bolje rezultate (*) postiže radijalni raspršivač. Najbolje podešenje tehničkih čimbenika raspršivanja (pokrivenost tretirane površine od 59,55 % i zanošenja tekućine od 21,10 %) ostvaruje se sa radijalnim raspršivačem te zelenom mlaznicom (TR 80015C), brzinom rada od 8 km/h, normom raspršivanja od 325 l/ha i radnim tlakom od 16,84 bar.Research is conducted on an apple orchard with two different types of orchard sprayers, axial (Hardi Zaturn) and radial (Hardi Arrow). The influence of major technical spraying factors (type of nozzle, working speed and spray volume) were observed on coverage of the treated area, average droplet diameter, number of droplets per cm2 and drift. The working speed of sprayer was set at 6 and 8 km/h, and spray volume on 250, 325 and 400 l/ha. In research, Lechler blue (TR 8003C), yellow (TR 8002C) and green (TR 80015C) nozzles were used. The research was set as three - factorial field experiment with 18 treatments in 4 repetitions, for each type of sprayer. Sixty water sensitive papers (WSP) were used for the treatment, which was processed with digital image analysis (DIA) and ImageJ software. The major technical spraying factors have a high significant statistical impact (**) on the main properties of the research. By decreasing the ISO number of nozzles and by increasing the working speed and spray volume, we found increasement of area coverage, number of droplets per cm2 and drift, and decreasement of average droplet diameter. By comparing the results of the research by axial and radial orchard sprayer in apple orchard, better results (*) were achieved with a radial sprayer. The best adjustment of technical spraying factors (area coverage of 59,55 % and 21,10 % of liquid drift) was achieved by a radial sprayer and with green nozzle (TR80015C), working speed of 8 km/h, spray volume of 325 l/ha, and working pressure of 16,84 bar