Loading-shovels are often put forward as the ultimate buck-raking tools, but they have got to be correctly kitted out for rigorous farm work.

Last year Liebherr decided to dip its toe in the agricultural market with a slightly modified version of its L534 wheeled loader.

This year the German construction kit manufacturer is back with its full farm spec Agri Contractor.

Launched seven years ago, the L534 was originally intended for the construction and waste industries.

Wide Goodyear 750/55R26 agricultural tyres, beefed up axles and a modified loader setup have been added to make the Agri Contractor what Liebherr hopes to be the ultimate clamp climber.

Given that by its very nature such a machine is likely to have a hefty price tag – £85,000 in this case – it is going to need to be able to tackle other jobs out of the silage season.

And, in the absence of mountains of chopped grass to shift in early spring, what better than a heap of muck to test the big machine’s capabilities?

At its heart, or rather in its tail, lies a 136hp John Deere four-cylinder engine and two variable displacement pumps to cater independently for loader and transmission requirements.

It is the L534’s hydrostatic drive that Liebherr claims to be the main differentiating factor from the competition.

Bolted to the engine, the dedicated load-sensing transmission pump provides oil-flow for two hydrostatic motors on the rear axle.

At low speed these swash-plate drive-units work together to provide maximum torque and pushing power, with a shaft connecting front and rear axles.

As speed increases and load drops off, one motor’s input is gradually diminished to boost efficiency and maintain engine revs at this faster pace.

Completely new operators will find the stepless transmission a doddle to master thanks to its simplicity.

Those more familiar with torque-converter gearboxes will take a little longer to settle in.

To get moving it is just a case of flicking off the parking brake rocker-switch and flipping the joystick trigger to select forwards or reverse.

Then a gentle squeeze of the throttle pedal sets the wheels in motion.

Easing off the gas slows oil-flow to provide smooth engine braking.

But when it is time for something a bit more challenging, a completely different driving style to that usually adopted with torque-converter transmissions is needed.

Instead of using plenty of right boot when the going gets tough, the hydrostatic propulsion unit actually requires the operator to ease off the throttle as engine load increases; for example, when clambering up on to the top of the heap with a full grab.

This approach allows pump swash-plate angle to open up And provide more oil flow to the motors as well as accessing the greater torque and power levels lower in the engine’s speed range.

It is a strange technique that takes a bit of getting used to, but once familiar with what is required it is surprising how much grunt is available from an engine of this size.

The loader itself requires little familiarisation.

A single joystick is used to activate the load-sensing hydraulic controls.

Both parallel linkage and Z-bar booms are available but after last year’s trials Liebherr found the single crowd/dump ram arrangement of the Z-bar setup to be more effective for silage-clamp work.

On the muckheap this seems to prove true. Running into the heap of wet, heavy muck with a 3.7m (12ft) wide buck-rake, there is no shortage of tear-out force and loader hydraulics respond exceptionally fast to any movement from the control stick.

In fact the speed with which they work takes a bit of getting used to.

Nearly faultless, the loader does disappoint in one area.

It is fast to lift, lower, crowd and dump, but when it comes to this final function it lets the side down.

Like many similar machines, because of the way the linkage geometry is arranged the fork tines never reach a completely vertical position.

This may be OK for clamp work, but when loading spreaders, the tines are quickly going to become clogged with stubborn lumps of dung and straw.

Overall, the L534 performs well and boasts bulldozer-like pushing power, even with its relatively small engine.

In fact, it is its hydrostatic transmission that scores highest because of its controllability.

With so much of its available power channelled through its wheels, the Agri Contractor has the potential to clear whole trailer-loads in one swipe, allowing more time for essential rolling on the clamp.

Weighing in at 12.5t, it is going to be more than capable in providing that all-important consolidation effect.

But will its equally hefty price tag tempt contractors away from more conventional machines?

Thirsty work?

Liebherr says a hydrostatic transmission is inherently more efficient than a torque-converter box and consequently a smaller engine is required for similar outputs.

On silage clamps in Ireland last year, the firm claims to have achieved an average fuel consumption of 13 litres/hour and says this is less than half of competitive machines.

www.liebherr.com