PERFORMANCE OF AN AIR-ASSIST FORESTRY BOOM SPRAYER

Air-assist, where a stream of high-velocity air is directed over or cl ose to the spray emitted from a nozzle, is used to improve deposition efficiency and to reduce spray drift with agricultural sprayers. Fores try industries are concerned with the same issues. This study was init iated to investigate air-assist as a means of improving spray penetrat ion and deposition from a boom sprayer while reducing drift potential in a canopy of wild red raspberry plants (Rubus idaeus L.), a weed com mon in Ontario forest regeneration sites. A small air-assist boom spra yer was built and two sets of experiments were conducted, one in a wal k-in wind tunnel and the other at a field site. Two air-assist configu rations were used: direct-assist and air-curtain. Results showed that both configurations increased spray penetration, providing improved sp ray deposition on targets located within the canopy. Air-assist also r educed the potential for drift under windy conditions. However, the ai r-curtain configuration was not effective in a crosswind situation.