Minimising the impacts of spray drift
Preventing spray drift involves not only maintaining due care and attention at all times when spraying agricultural chemicals, but also knowing how to apply the product correctly. Examples of chemical misuse that can result in spray drift include:
- violating a specific use instruction on the label – notably one designed to limit spray drift, such as optimal spray droplet sizes
- incorrectly assessing the prevailing conditions (wind direction, speed, etc.).
Label instructions serve a vital purpose. By following them, you increase the chance of the chemical reaching its target, reducing the potential of spray drift. You should maintain control of all spray operations – stop spraying or stop the contractor spraying if the conditions are not right.
Tips for spraying correctly
- Keep your knowledge of application methods up to date. Attend equipment manufacturer or product manufacturer field days when these are organised in your area.
- Read the agricultural chemical product label and follow the instructions accurately. Many products have specific spray drift management instructions dealing with optimal weather conditions and spray equipment.
- If you don't understand a label instruction, ask someone who does before commencing the application. Product labels provide contact details of the manufacturer who can provide reliable technical advice to assist you if necessary.
- If you're not sure about what you're doing, consider engaging a professional contractor.
Be careful of surrounding areas
- Identify sensitive crops and areas (e.g. creeks and streams, livestock paddocks or schools) around the area where you intend to spray, and let the spray operator know about these areas.
- Discuss your spray plans with your neighbours and contractors. Good communication can often avoid complaints from neighbours or prevent misunderstandings and unnecessary conflict.
- If possible, maintain a buffer zone between areas of application and areas where there is a risk of damage from spray drift.
Use the right equipment
- Select equipment (applicators and nozzles) that will give you the correct droplet size range to minimise drift and maximise efficiency. Smaller droplets are more likely to drift. Always use equipment as recommended by the manufacturer.
- Maintain the correct boom height for the nozzles being used. For some products the maximum boom height is a label instruction. If spray is being applied aerially, make sure it is released only when the aircraft has levelled out above the crop and is turned off before ascending to turn.
- Calibrate the equipment correctly. Check with the manufacturer to find out how to correctly calibrate the equipment.
Check weather conditions
- Measure and record the weather conditions before and after the applications or as directed by the label. If you think they have changed, stop and measure them during the application as well.
- Spray only in favourable weather conditions. Ideal wind speeds are between 3-15km/h.
- During spraying, wind should be blowing steadily. Light and variable or gusty winds make it difficult to predict where spray will go.
- Spraying should not be carried out under calm or still conditions. Under calm conditions, droplets are more likely to remain suspended in the air.
- Ideally, wind should be blowing away from susceptible crops. If not, try leaving a buffer zone.
- Avoid spraying in temperatures near or above 30°C and when humidity is low as spray droplet size may be reduced, increasing the risk of spray drift.
- Do not spray when inversion conditions exist. Visual indicators include no wind, fog, dew, frost and smoke or dust hanging in the air or forming distinct layers. Inversion conditions are very prevalent in Australia.
- Keep detailed records of each spray application. Good records will prove beneficial if complaints are made, particularly if you need to accurately recall information months after a spray event. Read more about record-keeping obligations. Be aware that some chemical labels contain instructions which also require particular records of each chemical application to be kept.
- Learn about ground distribution of herbicides.
- Learn more about use of agricultural and veterinary chemicals.
- Read about managing chemical spray drift in the Guide for Queensland's rural industry (PDF, 1.45MB).
- Read the CSIRO's spray drift management report on managing spray application risks.