Variable rate pesticide application holds great potential in precision farming with high efficiency of pesticide use and minimised environmental contamination, while application efficiency depends strongly on the accuracy of the discharge rate on the target area. This study is an initial part of the development of a variable rate sprayer to quantify droplet travel time with four types of nozzle at four different liquid pressures and at four forward speeds using a moisture sensor and laser technology. Performance of droplet deposition at different instants was investigated by moving belt and fluorescent tracer. Sprayer forward speed had a significant influence on droplet transport time, while liquid pressure had less influence. Sample positions chosen at below the nozzle and midway between two nozzles on the boom produced little difference in droplet transport time. Dynamic deposition results indicated that accumulated deposition at the peak point is 37·1%, 33·6% and 29·2% of the total deposition with a flat fan nozzle, low drift nozzle, and hollow core nozzle, respectively.
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