Have a rummage in Matt Redman’s spray nozzle storage box and a familiar selection of shapes and sizes comes to light.
An 03 Syngenta Defy, an Amistar-branded Hypro Guardian Air of the same size, 04 and 06 BFS Air Bubble Jets – and yes, a set of traditional flat fan tips.
“To be honest, the flat fans have pretty much dropped off the list of nozzles I use because the Defy is so effective,” says Mr Redman.
“I use it for all pre- and post-emergence herbicides on arable crops up to T1, and maybe up to T2 in good spraying conditions.”
The Defy’s 83deg fan means the boom can be set higher for autumn work, where the target is either the soil surface or young grass and broadleaved weeds, to minimise risk of the boom hitting the deck.
But being less drifty than a regular flat fan nozzle, positioning the boom 70cm above the ground rather than the customary 50cm above the target does not necessarily induce more drift.
Boom height has become more of a consideration since Mr Redman upgraded his spraying outfit from 24m to 32m after winning the Syngenta Farm Sprayer Operator of the Year title in 2014.
“There was nothing wrong with the 3,000-litre, 24m Househam sprayer I used before,” he says.
“But I wanted to progress the contract spraying business and felt I needed equipment with features that farms don’t already have themselves – such as GPS section control.”
A five-year old 3,500-litre Bateman RB35 provided the upgrade opportunity, with the budget then stretching to extra sections for the boom to increase working width – and therefore work rate – from 28m to 32m.
The newly configured boom has also added flexibility for working on farms and crops with different tramline dimensions.
“I can now spray at 12m, 24m, 30m or 32m, so the sprayer will fit most tramline spacings,” Mr Redman explains.
“That’s vital when you’re contract spraying – at home we have 24m tramlines, but 30m is becoming more popular as more farms have gone from 4m to 6m drills.”
The boom rejig also involved replacing the standard nozzle bodies on the single spray line with the Hypro Duo React twin outlet bodies.
Bateman Engineering installed a couple of extra solenoid valves, but otherwise the job was handled in the farm workshop with the help of a harvest student.
“I wanted the benefits of being able to switch between different nozzles easily, which I had on the Househam using offset nozzles on a single line, but converting the Bateman to twin lines would have been too costly,” says Mr Redman.
“Besides, the Duo React system is a much neater installation, with all the nozzles correctly positioned 0.5m apart rather than offset slightly, and it’s simpler and lighter than a twin line set-up.”
The Duo React body has one single nozzle outlet and a four-nozzle turret, so the sprayer can carry five nozzle sets with two in the “active” positions.
A couple of rocker switches in the cab select either nozzle or both at the same time.
A typical combination on Mr Redman’s Bateman is the Defy variable pressure, inclined spray nozzle and the air inclusion Guardian Air, which produces a coarser, less drift prone spray with air-filled droplets that collapse on impact with target leaves instead of remaining intact and bouncing off.
“The Guardian Air is the mainstay for everything I don’t spray with the Defy,” says Mr Redman.
“It’s reliable and it’s short, which means it’s less vulnerable to damage than other air inclusion nozzles, which tend to be bigger in all directions.
“I also like the way the metering disc stays in place when you take them out of the nozzle body; it means there’s less risk of losing them or ending up with a box full of discs and empty nozzles.”
The 03 size has proved a good all-rounder, he adds, operating typically at 3 bar or a bit higher to reduce droplet size a touch when conditions allow and having the ability to maintain a good pattern when the pressure drops upon slowing down when working in smaller fields, climbing a bank or making a headland turn.
Equally, the Defy/Guardian Air combination on the Duo React bodies is ideal for situations where optimum coverage is the priority in the body of a field, but effective drift control is needed to meet Leraps demands alongside ditches and streams.
“It’s also handy being able to get extra drift control just by flicking a couple of switches to avoid spray going off on to field margins and into hedges and neighbouring crops,” he points out.
Forwards v backwards
Operators have differing views in the “forwards versus rearwards” inclined spray debate, but Mr Redman follows Syngenta’s recommendation of alternating the Defy nozzles forward to get good horizontal movement for intercepting small blackgrass plants and backward to achieve all-over coverage of soil clods with pre-emergence sprays.
The Amistar Guardian Air tips are set up in the same way for fungicide applications up to T3 before being repositioned to all face backwards thereafter.
“The alternating arrangement seems to work well when you want good coverage from top to bottom,” he points out. “But for later applications, when the top of the crop is the target, you want the spray settling more gently with less forward movement and with the back of the ear getting a good coating.”
Spraying vertically is now confined to spraying grassland for weed control, using either the regular flat fan jets or air inclusion 06 Air Bubble Jets.
The 06 nozzles get used for 100-150 litre/ha grassland sprays but where maximum coverage is needed for big, difficult weeds like mature nettles, the flat fans come into their own.
“Using two 03 flat fan nozzles together delivers 200 litre/ha in a very fine spray at a decent working speed,” says Mr Redman. “It’s another good reason for having twin line capability on the sprayer.”