17 September 1999


A contractors armoury of cultivation equipment is

often extensive, with a wide variety of kit needed

to tackle the many soil types and conditions

encountered. Geoff Ashcroft reports

Devon-based contractor Troy Stuart has adopted a simplistic – and it would appear effective – approach to cultivations and drilling on the 2023ha (5000 acres) of autumn-sown crops he prepares each year for customers.

It centres on a 4.5m Quivogne disc harrow used in combination with a 5.6m-wide Lynx Sumo combination press – but not any old press. Mr Stuarts version was built by Lynx Engineering to suit his own requirements and uses a combination of tyres and breaker rings.

"We used to rely quite heavily on the plough for primary cultivation work, but in the last few seasons, the plough has been bad news with clods and so it has made way for disc harrows," he explains.

"Soil types in this area vary from sand to clay and we needed to find a simple, fast and effective solution to seedbed preparation on any soil type – and the plough isnt it."

Aiming to get from stubble to drilled seedbed in two passes is a challenge at the best of times – for Mr Stuart to achieve it on almost any soil type must surely be a recipe for business longevity.

"Fewer passes means more timely drilling and, more importantly for our customers, it offers lower establishment costs," he says.

To achieve better crumbling and moisture preservation behind the discs, Mr Stuart first tried a set of breaker rolls with some success, but says it didnt suit all conditions.

Ring problems

"With a bit of dampness in the soil, the rings would start to pickup. So we tried a Lynx rubber-tyred press roll behind the discs and it proved successful in the areas where the rings wouldnt work properly."

"What we really needed was a press which combined the action of both rings and rubber tyres and so I pooled ideas with Lynx Engineering to help develop the Sumo combination press," he says.

The press uses a row of breaker rings followed by a row of tyres – the latter uses 22.5-inch diameter ex-commercial vehicle tyres which float on an axle.

A hydraulic drawbar allows the Sumo press to be tilted fore or aft, so its weight is applied either to the breaker rings or the tyres, or be distributed across both axles to suit prevailing soil conditions. And with an operating weight of about 1t/metre, Mr Stuart reckons the press makes short work of turning soil into a respectable seedbed.

"Its a combination which allows us to achieve the best results on just about any soil type. On sandy soils, we transfer weight onto the packer tyres, while on clay soils we use only the breaker rings," he says.

Mr Stuart adds that one pass with the discs and press now leaves the seedbed about 80% prepared. This is followed by one pass with a 6m wide Kuhn power harrow drill combination and the gate is shut.

"Because the Sumo press has done most of the work, the power harrow/drill can work at considerable speed, just to finish off," he says.

However, getting the cultivation technique right is only part of the equation for Mr Stuart. In the narrow lanes of Devon, manoeuvrability presents something of an additional challenge for his cultivation train.

And it perhaps explains why a 280hp John Deere 8400 is used to power the combination.

"Average field sizes in this area are still only about 10 acres and many are gently rolling, so we need plenty of horsepower," he says. "Also, gateways are tight and lanes are narrow, so we cannot fit duals to the tractor – it means a heavy, powerful machine is used."

With 280hp up front, the combination can work at speeds of up to 12kph which means an output of 28-32ha/day (70-80 acres) is possible.

"When its time to move to the next field, the discs and press both fold vertically to get the transport width down to about 2.8m. Then tilting the presss drawbar has the effect of bringing the road wheels closer to the disc harrows so the whole combination, despite its size, follows very well," he says.n

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