Reducing Spray Drift

Bulletin 816-00

Shielded Sprayer Boom

Partially covering a sprayer boom with a shield has been shown helpful in reducing spray drift (Fig. 16). Researchers have conducted wind tunnel tests to determine the effect of having a shield near a nozzle on the path droplets follow after they are released from the nozzle. As shown on Figure 17, a shield behind the nozzle is effective in altering the flight paths of droplets so that they are diverted toward the plant canopy. Results from laboratory tests conducted at the University of Missouri indicated that a mechanical shield could reduce spray drift deposit by up to 70 percent.

Fig.16. Partially covering a spray boom with a shield may reduce spray drift.

Fig.17. Shields can alter flight paths of droplets.

Tests conducted in Ohio under field conditions (Fig. 18) generally showed reduction in drift deposits of up to 65 percent with the shield. However in three of the 11 tests, there was an increase in drift deposits with the shield. The researchers indicated that operating conditions, prevailing wind velocity, and size and configuration of the shield greatly influence the reduction of drift deposits. For example, a shield was most beneficial at the highest wind speed/ground-speed combinations tested.

Fig.18. Field tests show using shields generally reduce drift.