The characteristics of the target and where it’s located are key factors influencing champion sprayer operator Nick Stevens’ choice of nozzles.

When the pressure’s on to get through a heavy crop-spraying workload, it can be tempting to throw caution to the wind and go for output over other considerations.

But, despite the challenging workload presented by the 1050ha (2600 acres) of combinable crops grown by A4 Farmers on two units near Calne, Wiltshire, it’s quality that counts for Mr Stevens.

Prevailing weather and the need to “get on” do have an influence, he says. “But spraying still has to be done responsibly and with the objective of doing the best possible job.”

The winner of last year’s Syngenta Farm Sprayer Operator of the Year award is an advocate of using the right nozzle for the job on the day and being prepared to change settings or the nozzles themselves if necessary.

“It depends on where the target is and what it’s like, and then what conditions are like at the time,” he says. “I might start with one set-up in the morning, but switch to a different pressure setting or a different nozzle altogether if spraying conditions change.”

FSOOTY winner’s nozzle choice (left to right): Hawk 03 angled fan Hypro 03 VP wide pressure range vertical fan Hypro Guardian Air 035 angled fan air inclusion Amistar 025 angled fan air inclusion.

Working for an operation that has brought two farms into one arable enterprise and taking recommendations from three agronomists can make for an interesting life.

“There isn’t always a clear-cut answer to product choice, combinations, rates and water volumes because there are so many factors to take into account,” Mr Stevens acknowledges. “So it’s interesting to see who recommends what and to have my input, especially on water volume, when it comes to making a final decision.”

As operator of A4 Farming’s 24m/4000-litre self-propelled sprayer, his preference is for 100 litres/ha wherever possible because of its significant output advantage over higher quantities.

“High water volumes may be suggested when there’s an issue about getting the spray to an awkward target – to grass weeds hidden by a forward rape canopy in the autumn, for example,” says Mr Stevens. “But those challenging situations can often be dealt through nozzle choice, pressure setting and working speed rather than increasing water volume so as not to lose too much in the way of output.”

His Sands SLc 4000 has two spray lines, mainly so that it can apply liquid fertiliser as well as pesticides. But having those two lines on the 24m five-section boom is useful for an operator prepared to switch nozzles about.

“When I’m out of the fertiliser season, I tend to put my main tips on that line so that if conditions change I can simply switch to a nozzle held in the triple bodies on the other line,” Mr Stevens says. “Or I might use both lines to put 100 litres/ha through two sets of nozzles to get 200 litres/ha water volume without having to change to bigger-capacity tips.”

Setting up the sprayer for any given job is made easier by having all the relevant data logged on the sprayer’s RDS Delta controller.

“I’ve entered all the data and my chosen settings for each nozzle, then carried out a jug calibration check and they’re all pretty much spot on,” says Mr Stevens. “So all I need do now is scroll through the different tips, select the one I’m going to use and the sprayer is about ready to go.”

This year, apart from trying some new stream nozzles for liquid fertiliser in place of the dribble bars used previously, he anticipates using four tips for most pesticide applications.

The 03 conventional flat-fan nozzles in vertical and angled formats provide a fine spray for most pre-emergence and post-emergence grassweed spraying 035 air inclusion tips (vertical and angled again) will mostly be used for stem and leaf targets and ear washing will be the 025 angled air inclusion jet’s main role.

Pre- and post-em treatments against blackgrass, brome and ryegrasses are the most challenging to get right when conditions are less than ideal.

“Seed-beds here tend to be rolled tight, but if they are left a bit cloddy, I’m looking for a set-up that will overcome the shadowing effect of the clods,” says Nick Stevens. “Arranging the 03 Hawk VP nozzle alternately angled forward and backward seems to do the trick.”

With post-emergence applications, the aim is to get a little lateral movement into the spray to help it hit spindly, upright targets.

“If there’s a little too much off-target drift with the Hawk, I’ll switch to an 035 Billericay Air Bubble Jet or Hypro Guardian Air and keep the pressure up to get a fine spray that’s a little coarser than from the Hawk tip,” says Mr Stevens. “But I might do the same when it’s too still. If there’s spray hanging about when I’m coming back down the field it’s time to use a nozzle and setting that will get it down on to the ground a bit more positively.”

Individual nozzle details are entered into the SAM sprayer’s RDS Delta controller and called up with the press of a button to save having to key-in flow, max-min pressure and speed, etc, every time. “Brown-Red” refers to the new Hypro Guardian Air 035 air inclusion tip.

Fungicide spraying will kick off with an 03 Hypro VP non-AI tip to produce a fine spray with a bit of movement that will work its way down on to the lower leaves without going to such a fine setting that it drifts off course.

For T2 applications, though, when the target area is further up the plant, the focus switches to air inclusion nozzles for precise targeting of the upper leaves with droplets big enough to get into the crop, but not so big that they bounce and splash off.

“When the pressure’s on, I’ll be looking to an 035 nozzle to give me a 5kph or so advantage over a smaller nozzle of the same type, but being aware that going faster can itself generate drift,” says Mr Stevens. “Using an angled spray can be an advantage in this situation, so I’m giving the Guardian Air 035 a try in place of the Air Bubble Jet this year. It also promises some flexibility in pressure setting without losing the spray pattern, so that will be useful.”

For the final yield protector on wheat, the ear-wash spray, it’s the now familiar 02 Amistar that is the tip of choice, with its rearward-angled fan designed to give the best droplet trajectory for coverage at the working speed specified.

In each of these situations, once the most appropriate nozzle has been chosen, Nick Stevens must use his judgement in adjusting the pressure setting to fine-tune droplet size for best target coverage with drift control.

But he does not leave it to chance: Instead water-sensitive paper strips are carried with the tips and other spraying essentials.

“You often can’t see the droplet on a leaf, especially when you’re spraying blackgrass, for example,” he says. “But you can soon see what the coverage is like by spraying over one of these strips laid on the ground or clipped to a cane at the right height for fungicide treatments and the same goes for checking how much spray is drifting off target.”

It all helps make informed nozzle and nozzle setting choices.