Harvesting Jersey Royals is an operation that demands complete reliability and performance from the kit that’s adapted to the constraints of the island’s potato industry. CPM takes a tour while harvest is in full swing.
Everything in Jersey is bespoke.
By Tom Allen-Stevens
Drive around the small, narrow roads of Jersey in May, and you won’t go far before you see the island’s potato harvest in action.
Chances are it’ll be the distinctive red livery of a Grimme harvester bringing in the crop – either a two-row or single-row machine. There’s also quite a fair chance the crop coming in will be for the Jersey Royal Company.
Set up in 2004 by a consortium of farmers, it’s now Jersey’s largest single potato producer and was bought in 2014 by Produce Investments. The company farms 1800ha (or 8200 vergées – the Jersey unit of land measurement) across the island, which means at any one time there could be 18 harvesters operating from a total fleet that comprises 17 single-row SE machines, six GT170s and five GZ1700s.
Looking after that fleet, as well as the company’s 96 John Deere tractors, its planters, bed-tillers and all the equipment in the packing and grading facility, is a team of 15 mechanics, headed up by senior maintenance engineer Ricky Gallon. “I’ve been in the role for two years, and I’m still getting my head round it, to be honest. It covers all the kit from winches to harvesters – there’s a lot of variety.”
Jersey’s just nine miles by five – smaller than Greater London – and lies 85 miles south of the English coast. But the land across the island varies, he explains. “It’s very heavy in the East, but sandy and light in the West. There’s a big difference in climate, too, though you wouldn’t believe it. The north coast gets the most rainfall and St Clements in the South/South East is 1-2°C warmer. It’s a bit of a microclimate and is known as the ‘Golden Mile’. Then there’s the côtils.”
These are steep, south-facing slopes on which the potatoes are planted and harvested by hand. It’s said that the first Jersey Royal potato was grown in 1880 on a côtil. Today, these areas form the earliest part of the uncovered crop, lifted in early to mid April, using ploughs that are winched up the hill, with the crop hand-picked.
Almost the entire Jersey potato crop is grown to this one kidney-shaped variety, with its distinctive flavour and paper-thin skins. For the Jersey Royal Company, it’s the only variety grown, with 20,000t graded, washed, packed and sent to the UK mainland on the same day, or day after they’re harvested. These are sold to a market that’s worth around £4000/t at the start of the season, with prices then declining fast.
“We sell to major supermarkets and harvest to orders that come into the packhouse that day,” says Ricky Gallon. “Typically, that’ll be 450-500t that we’ll need to bring in – there’s no storing the crop in the fridge for a few days, it has to go straight off to the mainland. This means we need a reliable harvest system, but one that’s also gentle on the crop – Jersey Royals are like eggs, very fragile with a skin that isn’t set.”
Around 300ha (1700 vergées) are grown for seed, and it’s at planting the focus on achieving a premium product starts. The company has a Grimme GL32B Auto Quad cup planter and two belt planters – a GL42K and GB215. “The Quad puts the seed deeper and it takes longer to emerge, but you can get better results. It’s set to 32in (80cm) rows,” he says.
“But around 80% of our crop is hand-planted, which is partly down to slopes and field size – the average is just 4.5 vergées (0.8ha). Precision is also very important for our premium crop. There’s no machine yet that can do as good a job as a hand-planter at placing the tubers so the chits are in the right direction.”
Spacing is also key, and it can be a job to maintain accuracy when you’re planting a kidney-shaped seed, he notes. “The belt planter can handle irregular-sized seed, but it’s graded to four or five sizes, and the larger tubers aren’t managed too well by a belt planter.”
There’s also the need to get a lot of seed in the ground in a short period. Following the previous harvest, land generally goes into either forage crops as a land swap with dairy colleagues within the farmer consortium, or green manures, which are mown in late autumn. Then in Jan, fields are ploughed, with one of five Lemken 4f ploughs or additional contractor equipment, power harrowed and planted on the same day. “We never plough too far ahead because of the weather.”
An application of fertiliser is placed at planting, 5cm to the side and below the tuber. “It puts the fertiliser within reach, but not too close to the tuber.”
Harvesting the bulk of the crop starts in mid April, and this is where Jersey growers value a smaller, more compact machine. “Everything in Jersey is bespoke – it’s a real problem with our roads restricting transport.”
Grimme has worked with farmers on the island to adapt harvesting kit to their requirements – the single-row SE harvester has a shortened bunker, for example. It’s an essential tool to open up fields and Ricky Gallon finds the machine’s agility and flexibility brings better overall results from Jersey’s small, sloping fields than the higher-capacity two-row machines.
When it comes to two-row harvesting, the GT170M tends to be the machine of choice on the island. Again, this has been modified for Jersey by Grimme, with the axle tucked in underneath on the right-hand side to comply with road-width restrictions. The picking-off table has also been adapted to take the standard team of six pickers, with waste put into a centre conveyor, rather than at the side.
“For us, getting the right spec from the crop starts in the field. As well as clods and stones and green tubers, anything over 55mm is waste – 50-100t/day can be wasted on size alone, making a total waste of 100-200t/day. The industry’s tried a number of steps to address this, but no one wants the oversized tubers, so they’re returned to the field.”
One feature of the GT170M he likes is Terra depth control (see panel below). “You dig normally for 100m, then turn the Terra Control on, and it automatically keeps the share at that height. It does a good job, although you have the option to dial out or in if you need to.”
There’s no digging web on the GT170M, but that doesn’t worry Ricky Gallon – “the less drops the better.
“Haulm separation is generally pretty good in normal conditions with all the harvesters. But in the wet, that’s when the MultiSep in the GT harvesters comes into its own – it does a fantastic job. You get a better presentation and finish, compared with the SE, that doesn’t have one.”
There’s functionality and features on the machines, but not too much to get to grips with, says Ricky Gallon. “That’s important for us, because our turnaround of staff can fluctuate – you need to be able to train people up quickly. There’s not too much to adjust on the machines, not too much to go wrong, and they just work for what they’re needed for.”
The main mechanical issues he’s had come down to driver error. “You be surprised how easy it is to bash into a wall on this island. We have had the odd web snap, but generally it’s a robust harvester, even in testing conditions. Machines of a lesser quality would be ripped apart.”
Part of Ricky Gallon’s responsibility is to ensure the harvester fleet works at peak performance throughout the season, as any drop in output or downtime can be very costly.
“We have leeway in the system, with 28 harvesters, of which we use only 18. But everything is serviced religiously every year. In Oct, we assess the machines and list the new parts we need – it’s not unusual to put in an order for £100,000. Clod rollers and webs are the main wearing parts.”
It’s a high cost, he admits, and at any one time, there’s around £85,000 of spares in store in case of breakdowns. “Grimme parts are expensive, but we wouldn’t substitute them for anything else – it’s a small price to pay compared with the cost of downtime. We’re a company that believes in premium quality, and that’s not just with the crop, but the kit used to harvest it – quality counts.”
Full of features and gentle on the crop
There are two models of the GT170 two-row potato harvester – the GT170M has a shorter front end, built for agility and maximum visibility, says Grimme. Easier to move from field to field and working in tight spaces, it’s the high-output harvester of choice for Jersey’s narrow roads and small fields.
It’s more powerful sibling is the GT170S – faster, even gentler to the crop, claims Grimme, and better suited to tough harvest conditions and high yielding crops. There’s a separate intake web which increases the sieving output and improves haulm separation, as it’s turned over for better presentation to the first haulm extraction unit.
Apart from this, the models are pretty much identical, and have a number of notable features and options that make them a popular choice across the UK, as well as in Jersey. Foremost among these is Terra Control, that earned Grimme a DLG Innovation award in 2005. The system uses special hydraulic cylinders, guided by the diablo as it runs over the ridge, to set the depth of the share. A strip of sensor tape inside the ram monitors the diablo position as it moves up and down and passes this information through to the control panel.
The result is the digging depth remains the same all the time, irrespective of how uneven the ground is and it’s independent for each row. Within Terra Control there are three functions – depth control, ridge pressure and depth sensitivity. The system allows the operator to adjust the depth control according to field conditions. So if working on sandy conditions, for example, additional pressure can be added to the potato ridge to improve flow without affecting digging depth.
The MultiSep ensures good trash separation occurs in cloddy, sticky conditions and with soil with small stones. Four roller pairs, each with a PU-segment roller and one plain rubber roller clean the crop. The Double-MultiSep has eight roller pairs and each can be independently set from the operator terminal to adjust hydraulic levelling adjustment and speed of the roller pairs. The height, distance adjustment and drive direction of the clod rollers can also all be set independently.
All the main hydraulics and electronic components of the GT170 have been swept to within the side frame of the machine to guard them from soil and damage and ensure smooth running. For maintenance, the wide opening side panels and chassis design ensure easy access to all components.
There are three harvesting system available: A mechanically driven rotary agitator is fitted as standard equipment. There’s also manual height adjustment in relation to the main web – to change the intensity of the agitation – or hydraulic adjustment is available as an option, to adjust the agitator while in work.
The hydraulic rocker agitator is an option that increases sieving but ensures very gentle harvesting, says Grimme, even in changeable conditions. The company’s CascadeSystem has a “wavy-web” system that performs in a powerful, effective but gentle way – important for large and heavy potatoes as well as in low temperatures.
GT170 – tech specs
