Chafer sprayers have been a stable sight at Potash Farm near March in Cambridgeshire during the past 11 years, with the farm taking delivery of its third Sentry machine last season.

Run by Mick Mottram, C J Mottram and Sons covers 567ha of owned, rented and contract farmed area. Growing wheat, barley, potatoes, sugar beet, mustard and beans, he has a number of crops to manage, meaning he requires a sprayer that’s up to the task. “With the variety of crops we grow, it’s important that we can clean the sprayer out and turn it around quickly to go straight back onto fields,” he explains.

Other than sugar beet harvesting, all management is done in-house, with cultivations ranging from full inversion with a plough to min-till.

Before first purchasing a Chafer machine, the farm ran two 24m sprayers to help avoid cross contamination with sugar beet inputs, but 11 years ago Mick decided to opt for a single 36m machine to tie in with the existing wheelings on the fields.

“By operating a larger sprayer, we don’t travel through the crops as many times and can cover fields faster – I was surprised at how much more I could do in a day with a 36m machine than with a 24m one,” observes spray operator, Barry Glover.

Spares and repairs

Although Mick considered the idea of a self-propelled machine, he couldn’t justify the cost. “I decided to visit Chafer to see the spares store and was impressed that the firm carried nearly every spare part the Sentry could possibly require. The site is also only just over an hour away, so I knew that if we had a breakdown, I could collect the necessary parts and be back on the farm in under three hours.

“Since then, we’ve had very few problems – Chafer has never let us down with parts and are always at the end of the phone. The firm is only made up of a small team, but it provides a personal touch that’s followed up with service.”

Running a policy of trading in his sprayer for a new one every five years, Mick’s latest purchase of a 5000-litre Sentry G Series is what he and Barry coin as a ‘step change’ in performance. “The first and second Sentry machines we had were similar, but this time we’ve noticed a real difference in capabilities and performance,” says Mick.

Boom levelling

Two of the most significant improvements operationally have been the boom flow and steering. “The boom levelling is a hundred times better than before, making the job so much better and easier,” says Barry. “The first two Sentrys we had included Chafer’s own contour levelling system, but the latest machine has a Norac system and it’s tremendous – hovering just about the ground exactly where you want it to be.

“Section control on the boom is now split into 2m sections with two 6m sections in the middle, which has made a lot of difference in reducing overlaps, helping us to reduce chemical usage,” he adds.

According to Barry, steering has been vastly improved, making his job easier. “On the last sprayer, if you backed it into a corner you’d have to flick a button to make it go straight, but now the sprayer locks the steering into a straight position.”

Water volumes

He’s also been impressed by how easy it is to change water volumes on the new Sentry. “The sprayer has two lines which you can use variable rates on, whereas the previous machines had a single line. If one of the lines is struggling for pressure, then both lines cut in.

“Now we’re working with higher water rates than previously, this works really well. The machine has two smaller fine droplet nozzles and this also makes a noticeable difference, we can use a weaker mixture without compromising our efficiency.”

As a result, both Barry and Mick anticipate they’ll be using less chemicals. “This will all be down to the sprayer, so it’s helping us get ahead of the game as far as reducing inputs is concerned,” comments Barry. “We can use anything from 100-400 l/ha and where we used to typically apply 100-120 l/ha this now averages 200 l/ha.”

Having two separate lines has made the increase in typical water volumes a simpler process. “Because of the two lines and the different nozzles, it’s now an instant change, saving a lot of time. Before I’d have to change all of the nozzles to apply a different rate, and with 72 nozzles, this could take 20 minutes. Because there are fewer ideal spray days, any time saved is useful,” adds Barry.

Cleaning up

With an improved rinse facility, it’s now much simpler and easier for him to thoroughly clean the sprayer between jobs, he believes. “It’s a case of going into the control box and selecting the type of rinse, and with the ePlumbing, I simply select how many litres of water to use from the clean water tank, press the button and it does it itself.”

The sprayer also features Chafer’s AirPurge which uses pressurised air to remove all liquids from the system. “Not only does this thoroughly clean the lines, it also helps with frost protection,” says Barry.

Additionally, the in-cab set-up has been vastly improved through the introduction of a TopCon screen, rather than having an entirely separate box to control guidance and boom controls. “With the last two sprayers I couldn’t see out of the right hand window because of all the different displays, but this has now been consolidated. A lot of thought has gone into how to make it easier to operate the sprayer from the tractor.”

However, Barry does note that other tractors have in-built displays of sufficient enough size to remove the requirement for a TopCon screen altogether.

Finer details

Regardless, even some of the finer details and finishing touches to the latest Sentry have impressed Barry. “Chafer has added protective stainless steel plates to a lot of the wear spots, to prevent damage to the paint and the machine. There are plates at every join and a protective sheet behind the tyres to stop mud hitting the nozzles, proving the firm does listen to feedback.

“It also has better boom lights which makes working at night much easier because the tractor lights just aren’t enough by themselves.”

Mick notes that there are a lot of sprayer options available on the market but he’s been suitably impressed with Chafer’s approach, machine performance and build quality. “Chafer provides us with great service, and with smaller weather windows to work in, this is so important to help us be operational as quickly as possible.”

This story is bonus content from our sprayers feature published in the April 2025 issue of CPM.