Development of an Accurate Vineyard Sprayer

Abstract

The goal in spraying plants with an air carrier sprayer is to deliver spray material onto the canopy in adequate amounts, in a uniform distribution, and with a minimal off-target loss, all in a timely manner. Spray droplets produced by hydraulic or air-shear atomization, are carried, to, through, and onto the plant canopy by air jets produced by the sprayer. The air turbulence and the spray distribution in the air stream are important to overall spray deposit within the canopy. When a traditional air carrier sprayer passes a plant, moving air and spray droplets are propelled into the canopy, but the shingling effect of the leaves, prevents many droplets from entering and covering the leaves inside. As the result, a lot of chemicals spill off the outer leaves and the differences in coverage at different points of the canopy are very large. Ideally, the spray delivery should match the profile of the plant. In traditional sprayer systems the spray stream is directed across into the plant canopy from different distances, which causes even larger differences in coverage at different points. The development of a turbulent air-jets nozzle helped to penetrate even dense canopies and more accurate deposit the droplets on different leaves on both sides. The turbulent air-jets can do it by rotating and vibrating the leaves. Using several turbulent air-jets nozzles helped to develop a profile-adjusted accurate vineyard sprayer. The first turbulent air-jets sprayer was tested in heavy dense cotton rows with very good results. Several prototypes of profile-adjusted vineyard sprayers using the turbulent air-jets nozzles, were tested in Australia and Israel with good results. In order to measure the deposition variability of the sprayers, a hand held vision analysis system was developed.