Test Method for Boom Suspension Influence on Spray Distribution, Part I: Experimental Study of Pesticide Application under a Moving Boom

The quality of pesticide spraying depends on boom movement. A conveyor with a shaking platform was built to analyse the influence of boom movements on spray distribution. It is able to generate uniform translations and rotational movements of a small boom under laboratory conditions. The overall ground spray distributions were studied using image analysis. Suitable representations and mathematical tools were considered to analyse the unevenness of ground spray distributions and to compare accurately spray patterns. The effects of boom height, boom speed and nozzle type on dynamic spray distributions were analysed and compared with stationary distributions. The effects of yaw and roll movements were also considered. Measurements of droplet size and velocity made with a phase Doppler analyser were added to complete the dynamic effect study. Tests were repeatable but some fluctuations were obtained when boom height increased. Static and dynamic distributions have the same overall unevenness but this unevenness is more important in dynamic conditions due to turbulence effects. Roll and yaw increase unevenness. For roll movements, changes in nozzle heights explain the variations. For yaw movements, over-dosed areas are observed where the nozzles have a small horizontal velocity.