23 August 2002

Why four rows are better than two for lifting

Moving from two-row

to four-row lifting can

lead to big savings in

potato harvesting

efficiency and economics.

Mervyn Bailey consults

the first UK grower to

use the machine before it

starts its second season

AFTER completing its initial harvest, the only four-row self-propelled Grimme SF3000 potato harvester in the UK is preparing for its second lifting campaign at Hall Farm, Wighton, near Wells, north Norfolk.

Last year, the newcomer worked alongside a trailed Grimme GZ 1700DLS, with the two machines lifting over 330ha (825 acres) of Lady Rosetta, Hermes, Saturna and Lady Claire crisping potatoes for grower John Harrison and his son James.

"The harvester saved much more on labour than I expected," says John Harrison. "The only change we are making for the coming season is fitting a front mounted topper to remove the desiccated haulm so we can travel a bit faster."

Previously, three trailed machines were used at Hall Farm with three tractors hired in and two tractor drivers employed.

"Replacing two trailed harvesters with a four-row machine was a logical step which has made a significant cost saving and simplified the harvesting operation," says Mr Harrison.

"I first saw the Grimme four-row in action at a potato event in Holland as it sailed across the wet field on its tracks. It appeared a very simple harvester for the performance it could achieve."

Only a few detail changes have been made to the German machine for the UK market, despite working on de-clodded 36in beds. Continental growers using the machine have no need to de-stone or de-clod and run on 30in beds.

To cope with the slim rows and avoid disturbing windrowed stone and clod, Grimme has kept the standard 1500mm lifting width of the two intakes but fitted two large flat discs that guide the sides of the two outer ridges on to the shares and web.

These discs fold in hydraulically to provide a 3.3m transport width, while the front axle track width is adjusted hydraulically to allow the wheels to run in the furrows between the ridges. Rubber tracks provide grip and flotation at the back of the machine.

Only one track and a large flotation tyre are used on two-row Grimme harvester. But adding a second 1500mm wide web to create the four-row version means there is simply not enough room for large tyres to fit under the harvester, so the SF3000 has tracks on both sides.

"The tracks have proven very effective at keeping the harvester afloat even in really wet conditions when trailers were leaving ruts," says Mr Harrison.

Hydraulic motors power the tracks, as well as the front wheels, and these allow a maximum road speed of 25kph plus a 0kph to 10kph working range. A 280hp Mercedes engine provides the grunt to move the 21t harvester and this is located above the webs behind the cab where it does not hinder the drivers view of the unloading elevator.

For road travel, the cab is positioned towards the front of the chassis, giving the driver a better view of oncoming traffic at road junctions and also lowers the overall height of the machine. For work, it slides backwards and upwards to provide the operator with a clear view of the lifting area.

The main harvesting functions are controlled via the armrest-mounted lever and side console, while harvesting information is provided by a monitor mounted to the right. Below this is a screen displaying images from several CCTV cameras, which enables the driver to keep a close eye on key areas of the harvester as well as crop flow and the performance of the cleaning system.

Up front, flat rollers follow the ridge contours to maintain a consistent digging depth, after which two 1500mm wide web units transport the crop to the rear of the harvester where two RS roller tables clean it.

The potatoes then move on to the cart elevator, which is made up of soft flexible plastic pockets. The elevator is a three-piece unit that folds in a Z shape to reduce overall transport width.

At 8ha/day (20 acres), the SF3000 can easily achieve twice the capacity of a trailed two-row harvester, says Mr Harrison. The only change to the system for this year has been to prepare the beds differently.

"For the first season we used a two-row bed former and this worked well enough, but this year we used a triple row bed former to create two complete beds with each pass rather than one bed and two halves. Although this meant that one of the outer bodies was running idle, it was the only way of creating twin beds effectively in one go." &#42

Above: Two rear tracks reduce ground compaction and lower the centre of gravity, which makes the harvester more stable when turning on headlands.

Left: "The Grimme SF3000 can easily exceed the output of two trailed two-row machines and provides a saving in machinery and labour," says Norfolk grower John Harrison.

Modifications needed to deal with wider de-clodded beds amount to a pair of large diameter discs to guide the sides of the two outer ridges on to the two 1500mm wide shares and digging webs.