A comparison of drift from hooded and open-boom agricultural sprayers

A recent development in drift-control for agricultural ground sprayers is the installation of a hood (or shroud) over the boom. Hoods are designed to provide a protected zone in which droplets can be sprayed and deposited on the target with limited interference from the wind. This study compared chemical drift using hooded and open-boom pesticide sprayers in various configurations. The hooded sprayer included an air-foil mounted on top of the hood, designed to re-direct the airflow and further decrease drift. The principal objective was to test the performance of the hood, the air-foil, and nozzle size in reducing drift. A fluorescent dye and water solution was sprayed adjacent to a series of parallel string collectors. The amount of drifting material was determined by rinsing the string and testing the fluorescence of the rinsewater. Wind speed and direction, temperature, and relative humidity were monitored during each field test so that the influence of weather conditions on drift could be assessed. Statistical and graphical comparisons were based on the development of a regression model to describe downwind drift for each sprayer configuration under a set of variable weather conditions. Only parameters found to be important to drift were included in the final model. These parameters included sprayer configuration, wind speed, temperature, and the interactions of configuration with wind speed and temperature. Results of the comparisons indicated that for a larger droplet spectrum, the hood reduced drift significantly, while for smaller droplets the hood was ineffective. The air-foil was found to have no influence on drift

Spray Drift Reduction with Shrouded Boom Sprayers

Downwind drift was measured from a standard boom sprayer and a shrouded boom sprayer. Using 8002 flat fan nozzles, the hooded sprayer provided a 180 to 275% reduction in drift. The effectiveness of the shroud is dependent upon the spray droplet spectrum