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’. 

Quick take:

  • 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.

Leah Garnett