Dealing with ultra-low spray deposits in experiments

For bed-grown crops, ideally the spray is applied evenly to the bed only, while no spray should be applied onto the paths between the beds. Usually these criteria cannot be fulfilled easily. The current study describes the development and use of a model to design adequate set-ups of nozzles on a sprayer boom optimized for bed-grown crops. Spray patterns of various single nozzles at different boom heights have been measured on a patternator. The model combines these spray patterns while varying nozzle types, nozzle spacing and the position and angling of end nozzles. Examples are given for designs using Lechler Varioselect fourfold nozzle bodies to find optimal solutions for beds with widths between 1.1 and 1.5 m and boom heights of 0.2 to 0.6 m above the crop, while being able to apply different dose rates depending on crop canopy height. A large number of potential set-ups are simulated, but only relatively few meet the requirements that can be defined by the user.