Estimating Off-Target Spray Deposition On The Ground Following The Aerial Application Of Glyphosate For Conifer Release In New Brunswick

This study examines off-target spray deposition resulting from three semi-operational herbicide applications made in wind speeds from 1.5 m/s to 4.2 m/s. In the first 30 m downwind of the target area spray deposition decreased to less than 10% of the nominal dosage rate and to less than 5% at a distance of 200 m. Regression equations were developed and used to predict off-target deposits. At a distance of 65 m, the current buffer zone width in New Brunswick, predicted deposits would be at best equivalent to 3.7% of the dosage rate and at worst 5.6% of the dosage rate. Given these results there are no plans to change the current buffer zone recommendation.