Aplicação de solução aquosa na pulverização com atomizador costal motorizado

Abstract

The difficulty of detection and quantification of drift comprise one of the challenges in application technology, especially in hydropneumatic equipment. The aim of this study was to evaluate the spatial dependence of the deposition of spray drift and the spectrum of drops of a motorized knapsack sprayer. Geostatistical analysis was used as a tool of spatial variability, being chosen the best model by the lower sum of squares Residual (SQR) and higher correlation coefficient (R²). For a further analysis, was performed a classical statistical design in randomized blocks in a split plot with four adjuvants (plots) and seven distances (subplots) scheme, resulting in 28 treatments with eight replications. The treatments consisted of three adjuvant formulations (mineral oil, silicone polymer and nonylphenol ethoxylate) + water and seven distances from the center spray (3.0 m, 6.0 m, 9.0 m, 12.0 m, 15.0 m, 18.0 m and 20.0 m), the conditions for spray nozzle working at a 45° angle to the ground. Blocks were the different directions and senses of application (north, northeast, east, southeast, south, southwest, west and northwest). We used an aqueous solution of brilliant blue dye + adjuvant for checking the deposition by spectrophotometer at 630 nm. For detection, we used glass 0.10 m x 0.10 m x 0.002 m plates, and for characterization of the drops, water sensitive paper labels. The drift was considered by the difference between the amount sprayed and the estimated amount of deposition. It was found the spraying showed spatial variability for all variables, and the wind, even in recommended conditions for pesticide application, focused deposition of spray applied in the northwest direction. The applied dose occurs only up to six meters from the center of spraying, the Median Volumetric Diameter of the droplets was 136 um and occurred drift from 71.50% to total volume applied.