12 March 1999

Big power with sensitivity

Pulling power and the ability

to perform spring top-work;

two contrasting performance

characteristics that justify

the high initial cost of a

big-power tracklayer at &#42 R

Philpot & Sons Barleylands

Farm, Billericay, in Essex.

BARLEYLANDS Farms very heavy, mostly London clay, means output is needed to get work done when conditions are right, says Peter Philpot.

"That means having lots of pulling power to handle big implements. But in the spring, the tracklayers low ground pressure comes into its own drilling vining peas; you have to eliminate seed-bed compaction as far as possible if you want to get a crop that will grow and ripen evenly."

For these reasons, and to help drive down crop establishment costs, rubber-track tractors will play an increasing role in the Philpot farming operations over the next few years.

"The aim is to replace two conventional wheeled tractors with one big tracklayer for every 2000 acres," says Peter Philpot. "It is a costly process at first, but, in the long term, reducing the number of tractors, implements and staff needed to cultivate and drill crops makes economic sense."

Initial experience with a hard-worked Caterpillar Challenger 75D proved the point. It clocked up 1000 hours in just nine weeks, running round the clock to get the most out of the machine.

Changed after a year for the latest-spec 340hp Claas-badged 75E – kitted out with a 0.75t home-built weight and toolbox on the nose – another is currently on the order books.

The implement line-up is being developed accordingly. The existing 75E works a 6.7m (22ft) set of Simba discs with either a ring packer or roller behind, a 12-furrow Gregoire-Besson on-land semi-mounted plough, and a hefty seven-tine Keeble subsoiler.

Drilling capacity has already been increased by swapping a 6m (20ft) conventional drill for an 8m (26ft) Vaderstad cultivator disc drill. In addition, a 10.2m (33ft 6in) Vaderstad Rexius Twin cultivator/roller combination is on its way to help streamline seed-bed preparation for a cropping programme comprising cereals, oilseed rape, linseed, vining peas and potatoes.

Of all these implements, it is the subsoiler that offers the biggest challenge to the tractors tractive performance. With sweep tines loosening stubbles ahead of seven subsoil tines set 60cm (2ft) apart and working typically 38cm (15in) deep, the fully-mounted implement takes some pulling through the farms heavy clay soils.

So much so, that even the Challengers hefty three-point linkage needs modifying a bit to cope. The tractor has not been found wanting in the traction department, though.

"A big-wheeled tractor would really struggle with this implement," Mr Philpot reckons. "You just cant get enough rubber on the ground and the tractor ends up bouncing as the tyres flex and struggle to find grip. The rubber tracks really put the power down."

At the same time, the long rubber tracks distribute the 15.5t all-up weight of the tractor sufficiently that it can be used to good effect drilling spring-sown crops.

"With tracks and a wider drill, we are seeing fewer and less obvious wheelings through the seed-bed and, with vining peas particularly, that helps produce a more even, better yielding crop," says Mr Philpot. &#42