Boston-based Scotts Precision Manufacturing has seen a gap in the market for converting older Grimme GT170 trailed potato harvesters into windrowing machines. Geoff Ashcroft finds out more.
According to Scotts Precision Manufacturing, windrowing potatoes has many advantages. It can create space when opening up headlands, it affords quicker trailer loading and can reduce crop damage by filling the harvester to avoid roll back on the main web.
However, its adoption among UK growers has been a slow and gradual process, as Derek Scott, managing director of Scotts Precision Manufacturing explains; “We are in a market that has shifted towards self-propelled bunker harvesters, and that means traditional lifting with several two-row harvesters is becoming less and less attractive.
“Yet for those still lifting with a trailed two row harvester, such as the popular Grimme GT170, there are considerable benefits to be gained from windrowing.”
He says that pre-topping ahead of lifting has also helped the practice, by removing haulm well in advance of lifting.
“All the haulm needs to be removed when windrowing, as the higher volume of trash can cause problems when harvesting,” he says.
Mr Scott was approached a couple of years back by a potato grower who had tried several windrowing systems, but was disappointed with the conveyor design and the overall performance on offer.
“We were asked if we could look at converting one of the customer’s GT170s into a machine suitable for windrowing,” he explains. “It was not a straightforward process and the machine we started with was a basic-spec harvester with limited cleaning capability. The whole machine needed a lot of supplementary work to make it suit his system.”
Derek Scott’s solution was to design a cross-conveyor that could bolt onto the GT170 as a direct replacement for the elevator system. His logic was to allow the two lifted rows to be moved gently over the pair of rows adjacent to the harvester, so they could be deposited into the centre of the next pair of rows, further over.
“Windrowers have tended to use a short conveyor across the back of the machine. So if you open a field up and just move four rows – two on the way up and two on the way back down in an anti-clockwise loop – there is not quite enough room to sit a trailed harvester and trailer where those four rows once were,” he explains. “The harvester elevator would have to be almost vertical, leading to fall damage, and the outside trailer wheels would nip the rows waiting to be lifted. You really need to move six rows, to open up enough space to work. Our conversion allows you to move eight, by moving the second set of four rows in a clockwise loop.”
It stands to reason then, that a wide, sliding cross conveyor would unlock the potential for better harvesting logistics.
“We needed a cross conveyor that offered enough operational flexibility to move the lifted crop over a much greater distance,” he says. “So we settled on a 5.3m conveyor, which has given the side-shift required.”
The five-section conveyor can be folded for transport and also includes two end sections that can be raised and lowered, to manage the drop height into the valley between two unlifted rows of potatoes.
“I also wanted the hydraulically-driven conveyor to be reversible – so we could move the crop either to the left or the right - along with infinite adjustment of its lateral position,” he says.
Such generous movement allows a maximum of eight 36 inch rows to be lifted without moving the crop twice. And importantly, the offset wheel can remain in its original position, as there is no need to place the crop into the valley where the wheel runs.
“There is so much flexibility with this type of windrowing kit,” he says. “Windrowing does not need trailers until the harvester arrives - so the process of lifting crop from the ground can start sooner. When the two-row trailed harvester starts lifting, it is working in a much heavier crop which means webs are filled and damage from roll-back is minimised.”
The £20,000 bolt-on kit comes fully assembled with all hydraulic hoses and cables for direct connection to the host harvester, picking up on the GT170’s existing elevator fixing points. This makes it easy enough to remove and refit the elevator, if needed.
The Scotts conversion also sees functionality integrated into the Grimme control box. The height-adjustable end sections are controlled by the original elevator swan-neck up/down controls, while a diverter valve - controlled in-cab from a toggle switch - sends hydraulic flow from what was the main elevator, to power either the cross-conveyor or its side-shift function.
When windrowing is done, the cross-conveyor folds within the harvester’s width for transport, and built-in safety features prevent accidental conveyor folding.
“We have developed this windrower conversion kit to be as integrated as possible,” explains Derek Scott. “It looks part of the existing machine and when customers want to revert to the original harvester, it simply unbolts allowing the elevator to be refitted.”
Reflecting on his first conversion two years ago, he adds that the track width was wrong on that first low-spec harvester and needed converting to 72 inch centres to provide adequate machine stability.
“We manufactured new wheel rims for narrower tyres but with a generous offset, so the harvester could follow the tractor,” he says.
Having now converted a second GT170 for the same customer, but starting with a higher-spec machine complete with a digging web and a double separator, the customer has ended up with two GT170 windrower conversions – one for dry conditions using the lower-spec harvester and one for wet, difficult conditions.
“What we have created is a conversion kit that is as functional on older GT170’s as it is on new models,” he says. “This provides a useful second life for those older harvesters, by making them straightforward to re-purpose for windrowing.”
Using a machine such as the GT170 two-row trailed harvester as a windrower allows two rows of potatoes to be lifted and gently placed in the valley between two untouched rows.
When these rows are lifted, the harvester tucks into the equivalent of four rows of crop. So a greater volume of potatoes go into the harvester, with the advantage of speeding up the lifting process while keeping a higher volume on the webs to help reduce crop damage. Trailer loading is also faster. Windrowing also makes it easier to open up a field, as Derek Scott explains.
“With our windrow conversion, it is possible to move up to eight 36 inch rows without moving the crop twice, and this creates enough space for a harvester with an offset wheel plus a tractor and trailer to sit in the field without nipping the crop,” he says. “And because a windrower simply lifts and relocates the crop, it can start working sooner, operating without trailers. So productivity will increase.”