Archive Article: 2001/03/09
AIR induction nozzles such as the bubble jet offer significant benefits, including extremely low drift, but they need using with care for best results.
"There will be around seven times less drift than from a conventional 3 bar fan nozzle," says Tom Robinson, application technology manager with Syngenta.
"The 3 star rating of many of them is also essential for LERAP buffers. They will keep some products alive by cutting drift to water," Mr Robinson adds.
The larger droplets are also good at penetrating a cereal crop to get at broadleaved weeds and for giving an even application of pre-emergence residual herbicides.
"Boom height is less critical than with fan jets. The bigger droplets have more momentum and arrive at the target more directly and evenly. They also tend to land more uniformly when spraying at speed because you do not get the wuffling barrier created by smaller drops," says Mr Robinson.
On the downside, air induction jets are more likely to block, especially tips with twin pre-orifice plates. "It pays to be even more careful than usual with your filtration and water supply. But cleaning the nozzles is not greatly different from the conventional types."
Larger droplets are not good on small targets, he notes. "Doubling the size of the spray drops means there are eight times fewer of them. That means post-em graminicides, which need good cover on small, often upward pointing leaves and potato blight sprays, which need overall cover in dense canopies, should not be sprayed with air induction nozzles.
"If you have a lot of hedges or obstructions that may catch the nozzles the short stubby versions of the tips are best. But if damage in unlikely, the long pointed types are very good," he says. *