Unlike conventional flat fan nozzles the output of one air inclusion nozzle design can be very different from another. Peter Hill finds out how operators are getting on with the latest introductions

Last year’s introduction of a range of air-inclusion nozzles based on the design of Syngenta’s Amistar tip opened up the benefits of that technology to a bigger range of applications using different sprayers and preferred operating speeds.

Despite producing the Guardian Air tip in seven sizes, manufacturer Hypro EU, near Cambridge, managed to give each tip much the same characteristics in terms of droplet size related to pressure and spray pattern consistency across a generous range of operating pressures.

“Each tip is individually crafted so that operators can switch from one size to another and get the same spray quality at a given pressure,” notes Roger James, product manager. “The nozzles produce around twice as many droplets within a narrow size range as other air inclusion designs at a particular pressure and there is excellent droplet distribution consistency across the 1 to 5 bar operating pressure range, which makes it a versatile option.”

For growers keen to improve fieldwork rates, like Andrew Myatt who farms near Cheltenham, Gloucestershire, a choice of nozzle sizes providing good target coverage at low water volumes is a welcome development.

“I use 100 litres/ha whenever possible to maximise work rate,” he says. “My main consideration is to choose a nozzle that offers good spray coverage at this volume.”

Mr Myatt uses the 035 size to operate his Bateman 24m self-propelled sprayer at a brisk 16kph on level ground before switching to a second line carrying 03 nozzles for when the sprayer is slowed by working on steeper land.

The 03 puts on the target volume at 14kph using the same 3 bar pressure, but if the speed falls to 12kph and pressure is adjusted to compensate, the spray pattern is unaffected and there is no appreciable change in droplet size.

This consistent performance across different sizes and pressure/volume combinations helps improve the quality and efficiency of pesticide applications, while also achieving effective drift control, says Mr James.

“Users have had the confidence to trim water volumes for improved output and efficiency and adjust pressures to fine-tune drift control performance,” he reports. “That’s all down to the consistent pattern that the nozzle produces across different flow rates and pressures, and the fact that it produces smaller droplets than other air-inclusion designs.”

Operators who used Hypro EU’s Guardian Air over the past 12 months also say they like being able to use the same nozzle for a range of different spray applications on cereals, oilseed rape and other combinable crops.

That is especially useful for contractors like Somerset operator Colin Brown, who tackles a wide range of crops for customers who have different likes and dislikes when it comes to crop spraying practices.

“I first looked at the Guardian Air nozzles because it was claimed to combine drift reduction with good spray coverage,” he says. “In my experience, that’s true; the spray does not become too coarse at lower pressures and the spray pattern holds up well. You can see this clearly looking across the boom when spraying.”

The 025 is Mr Brown’s preferred choice, putting on 100 litres/ha at 12kph to get high workrates out of his Agribuggy sprayer. But if customers want him to use a higher water volume, he is happy to oblige, safe in the knowledge that he can switch to a different nozzle size and still get the same spray quality.

“The comments and feedback we’ve had from these and other growers who’ve used the new nozzles have confirmed what we set out to achieve with Guardian Air,” says Roger James. “It delivers all the drift control advantages of the air inclusion concept, but with few compromises in terms of performance and usability across a range of applications.”