Spray drift - why is it still happening
Despite an abundance of information on spray application being available, we continue to see widespread incidents of crop damage each year. A key to avoiding spray drift is understanding the difference between ‘day wind’ and ‘inversion wind’.
Most incidents of spray drift result from ‘inversion drift’, i.e. not drift from an adjacent sprayed area but from one or more sources some distance from the affected site.
Applicators need to understand the difference between ‘day wind’ and ‘inversion wind’, and how these affect the movement of spray droplets.
Spraying should occur when there is ‘day wind’, which has a turbulent motion and is much more likely to pull any ﬁne droplets to the ground within a reasonable distance.
Spraying under inversion conditions is extremely high risk and prohibited on many product labels— that means it is illegal.
Mary O’Brien, Educator, chemical use best practice, Mary O’Brien Rural Enterprises P/L, Dalby, Queensland
IREC Farmers' Newsletter No. 197 — Autumn 2017. Read the full newsletter here.