The Grains Research and Development Corporation (GRDC) is calling on all growers to ensure they are following best practice when it comes to spraying crops to reduce the risk of spray drift.
Any herbicide has the potential to drift, but by maximising the amount reaching the target, growers can minimise any herbicide or pesticide reaching off-target areas, improving effectiveness and reducing any potential damage to off-target crops or areas.
The GRDC suggests growers operate within the weather guidelines and adopt the following practices to reduce spray drift risk.
- Ensure that the spray droplet spectrum is optimised to maximise efficacy and minimise the opportunity for droplets to evaporate down to drift-prone size before reaching the target. Use the coarsest droplets possible and avoid wetters that increase drift potential.
- Operate machinery at optimum speed to maximise the boom’s stability and minimise the machine’s aerodynamic effect on airflow behind the machine and boom.
- Keep the boom height as low as possible to reduce the time that droplets are in the air and to take advantage of lower wind speed normally experienced near the surface.
- Plan ahead and be prepared to adjust operations to combat weather variations.
- Be sure to take into account the local microclimatic conditions, especially at night.
- Continually monitor conditions at the site and at a height representative of the spray zone and adjust operating practices for current conditions.
- Use on-board weather stations, smoke devices or ribbons attached to booms and fence lines to assist in the detection of variations in wind direction and speed. If using smoke devices, be mindful that the initial smoke rise will be due to the inherent heat of the source.
- Take extra care when applying pesticides over partially bare ground, which is hot and conducive to rapid evaporation and thermals.
- Avoid spraying an hour before sunset if an inversion is likely and for an hour-and-a-half after sunrise if an inversion occurred overnight (variations of wind speed and direction are likely to be unpredictable).
- Ensure that adequate buffers are maintained to protect sensitive areas.
The GRDC has a number of resources available to assist growers, including the Weather Essentials booklet, Stray Inversions Fact Sheet, Practical Spray Tips Face Sheet and the Nozzle Selection Guide.
See also the NSW Department of Primary Industries page.
Ellen McNamara, Cox Inall Communications
0429 897 129