10 August 2001

Baled out by a stack wrap


By Andy Collings

FARM manager Bill Welling had a problem. Last year he made 8000 big square bales, mostly straw, but a significant number from 500 acres of threshed grass from his seed grass enterprise. But when it came to selling the bales, weather damage cut his returns disastrously.

He estimates that, despite diligent attention to stack sheeting, a third were totally ruined, a third were damaged and had to be discounted and only a third could command a reasonable price.

"It was just not good enough," he says. "The net result was that we were hardly being paid to cart them off the field."

This year it could all be different. Mr Welling, based at Manor Farm, Woodmancott, Hants, is trying out a Danish machine which, through the use of plastic film, can provide a relatively economical weatherproof way of storing bales of hay or straw.

Called the Pomi Stack Wrapper (Pomi is derived from the inventors initials), the unit employs four rolls of 1m wide stretch film to encompass bale stacks completely, including a layer beneath them.

Both round and square bales can be used with the number of bales in each vertical slice dictated by their size. For example, five large Hesston bales or seven Hesston mini bales can be stacked.

The unit has a barn-shaped profile with a clearance height of 3.6m. A 19hp, two-cylinder Ruggerini diesel engine provides hydraulic power to drive twin chains which circumnavigate the frame drawing with it the four film dispensers.

At the beginning of the operation film is drawn out from the rollers to provide a hoop of plastic film six or more layers in depth. The next stage is for this hoop to be pushed out from the centre of the machine on hydraulically powered chains running on horizontal arms. At the same time more layers of film are run off to provide a continuation of coverage.

Once in position the first vertical section of bales can be stacked on the prepared film. When, say, seven bales are being stacked in the first layer, there would be three to the left, three to the right, and one centred on the top, the space either side of the top bale and between the two piles of three bales is used for ventilation.

"The point to note is that the Stack Wrapper does not wrap them in the sense that a bale is wrapped individually," says Mr Welling. "It is a covering which also allows the bales to be ventilated and avoid moulds appearing."

When the first stack is completed two arms are extended to push against the bales and move the machine forwards to provide room for the next stack to be positioned. As the machine moves forwards more film is run out.

The result is a continuous film-wrapped stack with its length only limited by available space. Mr Welling intends to place them on headlands used as set-aside.

Operating the Stack Wrapper is either through a set of buttons or, more conveniently, by a remote control which can initiate the whole covering sequence automatically.

Mr Welling is the first to concede that starting the stack calls for a degree of care to ensure that the bales remain upright.

"It is probably best to park a trailer behind to support them," he says. "They need to be secure when they are pushed against to move the machine forward. There is no problem when there are several stacks in position."

Other attention to detail can also make a difference to keeping quality. Building in a westerly direction so the film ends do not face prevailing winds which could lift them is recommended. This direction could also allow better ventilation through the open-ended stack.

When moving the machine from field to field its wheels are moved into a transport position to allow it to be towed from one end.

Mr Welling sees the Stack Wrapper as a radically new and effective way of storing lots of bales without the cost of erecting buildings.

"There are no sheets to remove or replace each time a lorry turns up for a load," he says. "All we will do is count how many bales are to be taken out and cut the film off at that point. And there is the added bonus of having the bales stored on the base of the stack being kept in good, saleable order. Film costs work out at about £1.50/t stored."

Mr Welling, who has the UK rights for the machine, sees contractors as being the biggest customers for the Stack Wrapper, but he also believes growers who sell straw to power stations could be potential customers.

"At £30,000 it is not a cheap option, but when it ensures that every bale can be sold for a good price then it is perhaps worth considering as a viable purchase," he says. "We intend to give the Stack Wrapper a thorough testing this season with view to marketing it the following year if all goes well." &#42