The effects of rates, nozzle tips and electrostatics on the quality of sprayed applications on soybean crop

There is an ongoing search for technologies that guarantee soybean productivity. Among them, the application of phytosanitary products stands out, since the sprayer is the most required implement during the agricultural production cycle and each error, in practice, represents a loss in the production process. With this in mind, the objective of this work was to evaluate the volume captured and the characteristics of the application in the different thirds of soybean plants with variations in hydraulic nozzles and spray volumes, as well as the use of electrification of the drops. To this end, a field experiment was conducted during the 2018/2019 summer harvest in an experimental area at the University of Rio Verde. The experimental design used was randomized blocks in a factorial scheme (3 × 4), with four repetitions, in which the first factor consisted of three variations of spray nozzles (simple fan, hollow cone and hollow cone with electrification of the drops). The second factor involved four application rates (50, 100, 150 and 200 l · ha–1). The variables evaluated were the number of drops per cm–2, percentage of coverage, volume median diameter (VMD) and the captured volume (μl · cm–2). According to the results, for the upper thirds, an increase in the application rate increased the volume of captured syrup. However, for the lower third, the factors evaluated did not interfere in this characteristic. The hydraulic tips influenced the density of droplets in the three thirds and the coverage only in the lower one. The increasing rates of application, increases the density of drops and percentage of coverage in the different thirds of the plants. The evaluated factors had no effect on the syrup distribution on the median abaxial surface of the leaves.