With diquat no longer approved for use, many potato growers will need to rethink their approach to haulm destruction from 2020. Geoff Ashcroft talks to one Yorkshire contractor who has been carrying out flail and spray operations for close to 20 years.
Phil Clappison is no stranger to potato growing.
In addition to growing a modest area at Cowlam Grange, Driffield, his family-run contracting business, TB Clappison, runs a fleet of 11 harvesters including two self-propelled models, plus a fleet of planters and destoners.
His workload is impressive and last season’s potato operation comprised 1,875 hectares of lifting and 1,215ha of destoning.
For the last 19 years he has operated a pair of Grimme three-bed toppers and was instrumental in developing the first prototype machine.
He says: “One-pass topping and spraying is all about managing the crop. It gives us control and flexibility, and by making spray applications from under the topper’s shielded hood, we are much less weather dependent.
“If you choose to spray as a separate pass with the farm sprayer and the weather conditions deteriorate, it will impact on your timings. And you’ll end up making a blanket spray application which will cost more, rather than applying only onto the beds.
“At the moment, we have the option of spraying or not spraying an entire field, and the choice of kit we use often comes down to what customers want to achieve with their crops,” he adds.
“So it’s important we can provide the option of pre-topping with a tractor, or waiting to top with the harvester, but the latter creates more dust and debris around the harvester, which can also impact on visibility.”
Mr Clappison says there is added convenience for growers choosing to top when harvesting, but he believes one-pass topping and spraying is the way forward despite the additional cost of making an extra pass through the crop.
“Pre-topping helps take pressure off the harvester driver and lets them concentrate on getting the crop out of the ground cleanly and with the minimum of damage,” he says.
“We’ve had no incidence of spreading blackleg or blight from flail topping. But it’s certainly an area that we’ll continue to watch.”
Output is typically 11-13ha/day, but the volume of crop canopy does have an impact on forward speed and output for the flail and spray system. “Every crop reacts differently and weather conditions also have a part to play.
Last summer’s hot and dry conditions did stress potato crops. Such conditions put many plants into survival mode, which made them hard to kill off,” he says. Control Some crops last season took two to three weeks to die back.
“If you are doing a decent job and make the most of applying Spotlight, for example, into the top of the topped stalk, then you can develop a lot of control over how the crop finishes.
But what we have found over the years is your destoning and bed forming processes need to be bob-on. There’s little margin for error when you go pre-topping, though our topper does have a side-shift facility. And we need to leave slightly bigger headlands for turning.”
However, operating the toppers on JCB Fastrac 4000- series tractors does help with in-field manoeuvrabilty, he says.
“With four-wheel steering, they’ll turn tightly. And given the area we cover, which can be a 60-mile radius of Cowlam Grange, these tractors are nippy and comfortable on the road too.”
The firm’s two Grimme KS6000 three-bed toppers comprise a front-mounted unit and two rear-mounted units on a butterfly folding frame.
In work,itgives the ability to remove haulm from three, 80-inch beds. “We first looked at pre-topping when sulphuric acid was on the way out,” he recalls.
“And in our first season of one-pass pre-topping and spraying, probably 2000 or 2001, we tried all sorts of different chemical rates to get the best results.
A lot of it was trial and error back then. Now there is much more information available.” His first machine, with serial number 0001, was the original prototype.
Built in the UK for Grimme specifically to suit UK conditions, the machine has undergone many modifications and improvements over the years. “It worked really well and the concept of pre-topping was to prove the way forward for us.
And a year later, I bought my second one. Flail and spray is a process which works really well for us.”
He reckons blade life is about 1,600ha and, having covered 24,000-28,000ha over the last nine years, the machines have been maintained with a ‘Trigger’s broom’ philosophy.
“The most we’ve pre-topped in one season is 9,000 acres. Every winter, our kit is overhauled and prepared for the next season, and painted if necessary.
We’ve added wear plates under the hoods on the back and front sides, we’ve added bigger wheels and tyres, modified wheel scrapers, and generally improved the toppers from their original design.”
The KS6000 operates with a shear bar under each hood and a range of blade lengths enabling the topper to follow the contour of an 80in bed or individual rows.
Under the profile of each hood are deflector plates which push the chopped haulm to the sides of each bed, laying material into the wheelings and leaving the bed clear for lifting.
These plates create a shielded spraying zone too, allowing desiccant to be applied.
Ideally, Mr Clappison likes to see 15-20cm of stalk left in placeto give the harvester’s haulm rollers something to get hold of, otherwise the risk of crop damage can be increased.
"There’s little margin for error when you go pre-topping, though our topper does have a side-shift facility"
“Achieving a consistent stalk height is helped by using scrapers on the topper’s depth wheels.
Otherwise all manner of soil and debris will lift the machine higher, affecting your trimmed height and the length of stalk which Spotlight has to travel down.”
He says the front topper’s working width enables it to trim up onto the top edge of the next row, to improve the clearing process where tractor tyres run.
“This overlap makes sure we deal with anything that sits between the rows, before the tractor wheels have a chance to push it out of sight,” he says.
“And with nozzles under each hood, we are band spraying.” Looking ahead, Mr Clappison is concerned about the future of potato growing in the UK.
He is currently involved with seed crop production, ware and fresh crop potatoes, with a considerable tonnage going for crisps and chip processing.
Though he says another extremely dry year is likely to be disastrous for him and many of his customers.
“It costs me about £1,830/acre to rent and grow my own crop,” he says. “If I hit my 16t/acre contracted tonnage and meet ‘spec one’, I can earn £127/acre.
But if my crop only makes ‘spec two’, I’ll lose £76/acre.
“The return on investment is mental. If you went on Dragons’ Den with an idea of growing potatoes, you’d be laughed out of the building,” he says.
“Processors need to be putting some extra money back into the job to ensure they have enough growers and a consistent supply to keep their customers happy.
“Growing potatoes seems to be very much on a par with the dairy industry’s challenges of milking cows,” he says.
Anticipating growers are likely to make a gradual shift into flail and spraying systems, Grimme re-introduced its three-bed topper at the last Lamma show after a five-year absence.
Adam Johnson, Grimme UK’s marketing manager, says: “Many growers have been making the most of diquat, so there’s been a void in topper sales for the last five or six years.
But with on-farm stocks of the chemical to be used by February 2020, we are preparing for a move back into haulm topping.”
Image: A shear bar on the Grimme KS600 helps to improve the quality of cut and ensure adequate haulm destruction.
The KS600 builds on the earlier KS6000’s proven format, though the firm is looking to develop the machine further.“We do see a need for much more advanced topping performance,” says Mr Johnson.
“And we are already looking at ways to improve the accuracy of the cutting height, machine configuration and the integration of spraying systems.“
With almost 20 years’ experience in haulm destruction, we have a good foundation on which to improve our topping systems.
Our aim is to develop the ultimate in flail and spray systems for potato growers,” he says.
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