• Journal of Biosystems Engineering
• /
• v.32 no.3
• /
• pp.145-152
• /
• 2007

Uniformity of spray deposit is one of the important factors in spray performance affecting efficacy of pest management. Distributions of spray deposit on artificial targets were measured and analyzed to enhance the efficiency of spray application. The research was studied to understand the deposition characteristics of spray droplets and to determine the optimum conditions of chemical application. The deposit and its pattern by the lower fan speed was more uniform and higher than that by the higher fan speed. The upward blasting distance was limited within 3 m, but the limit to the ground level was expanded the distance more than 3.5 m because of the accumulated droplets. When the fan speed was higher at the distance of 2.5 m, deposit reached to maximum. When the distance increased, deposit was getting lower. At the both fan speeds, the deposit was concentrated below $30^{\circ}$ because of the gravitation and the resistance of wind. This research can be useful in designing an orchard sprayer and its operation for various tree canopies. To achieve a uniform distribution of deposit using the air-blast type orchard sprayer, the application rate from the middle boom should be increased as the air velocity to the upward increased. The spray rate to the side boom should be limited in a minimal level.