22 September 1995

Gantry meets with approval – but lacks cash

By Peter Hill

SIX years after the first attempt to introduce a commercial "gantry" field tractor, plans are being formulated to relaunch the project. A second-generation design is on the drawing board, with more power and a more efficient hydrostatic power system which includes four-wheel drive.

The only element missing, says Oxfordshire farmer David Dowler, is the finance needed to get the project off the ground and see it through to commercial success.

"Weve been quiet over the past few years but I have a feeling that now is a good time to launch the gantry concept again," says Mr Dowler.

"There is even greater sensitivity about soil compaction than when we launched the original gantry, with farmers now prepared to spend more, in terms of tyre equipment and wider working implements, to combat it."

With two or three good years behind them, he adds, arable farmers have more cash to invest in new equipment and are more inclined to try new ideas.

Only a handful of the 12m (40ft) Dowler Gantry vehicles launched at the Cereals 89 event found buyers and all went for soil research rather than commercial use. With hydrostatic drive wheels mounted on either end of a monocoque construction chassis, the vehicle could be equipped to perform soil working operations such as cultivations and drilling, and crop treatments such as spraying and fertiliser application, always using the same wheelings.

Concentrating wheelings in this way would keep soil compaction to a minimum, leading to yield improvements and progressively reducing the energy needed to cultivate soils for following crops. The vehicle also provides a stable base for accurate application of sprays and fertiliser.

"Work at the Silsoe Research Institute with gantry vehicles has shown significant crop yield and soil structure improvements, while researchers in Holland have made big savings in fertiliser and sprays from precision application using a gantry," says David Dowler. "With an improved machine, perhaps bigger farming operations would now be prepared to invest in these advantages."

One farmer already convinced of the concept is Tim Coulton who grows 1310ha (3233 acres) of arable crops, mostly under management contracts, in Northamp-tonshire. He bought the gantry used on David Dowlers farm and has effectively become the first grower to use the device commercially.

"We used the gantry to broadcast 80 acres of cereals and 200 acres of oilseed rape last year, and we used it for a mid-flower spray in the rape as well," says Mr Coulton. "This year, we shall do a lot more with it."

He says the gantry is well-suited to broadcasting seed which is a regular technique on the heavy land farm. For one thing, it automatically marks out the field for following operations.

"One of the biggest attractions of investing in a gantry is you can adapt low-cost equipment to go with it," says Mr Coulton. "We have a 12m Nodet pneumatic spreader for seed and fertiliser application, with light spring tine sections from a Temple Harrow Comb used to scuffle the seed in."

All principle cultivations – either ploughing or discing, followed by rolling – are carried out by conventional big-capacity tractors and implements to move ground before weather deteriorates.

"Trying to perform all field operations with the gantry alone would be very difficult with the current machine; a more powerful version with greater traction would be better," says Mr Coulton. "But at least we are moving in the right direction." &#42