Almost every pass of the spray rig over a paddock will result in a small amount of the applied product remaining in the air after the spray has been released from the nozzles.

When weather conditions are suitable for spraying, the majority of the product that has become airborne will usually settle back to the ground within a few hundred metres from where it was released, often in the same paddock.

However, if too much of the product is left in the air due to poor nozzle choice, booms being set too high, spraying at high speeds or spraying during the wrong conditions, the consequences can be considerable.

The off-target movement of spray that results in damage to a sensitive area or crop is always the result of poor planning or a bad decision by the spray operator.

Note

GRDC maintains a Spray Drift page which conditions additional information on spray drift management. Go to: Spray Drift.

Importance of managing spray drift

Apart from the financial incentive to get as much of the product as you can to the target area, there are many other good reasons to minimise spray drift, some of these include:

• protection of human health – your family, neighbours and community;

• protection of trade by avoiding residues on crops and pastures, particularly where residue limits have not been established in the destination market;

• protection of farm vegetation, native vegetation, animal habitats and biodiversity;

• protection of water quality, including water for human consumption, stock use and irrigation;

• protection of aquatic organisms; and

• protection of beneficial insects (predators and pollinators) and their refuges.

To reduce these potential impacts it is important for the spray operator to be able to make changes when required. This necessitates the ability to interpret information, to plan and for the operator to be prepared to change the things they have control over.

It is also important that the spray operator is able to make good decisions in order to manage the things they do not have direct control over, such as the weather. This includes the decision to stop spraying when conditions become unsuitable.