Influence of travel speed on spray deposition uniformity from an air-assisted variable-rate sprayer

Abstract

<abstract> <bold>Abstract.</bold> A newly developed LiDAR-guided air-assisted variable-rate sprayer for nursery and orchard applications was tested at various travel speeds to compare its spray deposition and coverage uniformity with constant-rate applications. Spray samplers, including nylon screens and water-sensitive papers (WSP), were mounted inside tree canopies to measure spray deposits and coverage. Experiments were conducted with six different size tree species in commercial nurseries and travel speeds ranged from 3.2 to 8.0 km h-1. Test results showed that variable-rate sprayer was able to adjust spray outputs to match canopy structures and travel speeds. For the variable-rate application, there were no significant variations in spray deposits and coverage for each tree species among the travel speeds of 3.2, 5.6 and 8.0 km h-1. The variable-rate application had significantly lower variations in spray deposits within canopies of different size trees than the constant spray application.