7 minute read
Tried and True
Brent Lilley found the
Pöttinger Terradisc
compact disc harrow was tough enough to handle rugged conditions in this 2015 review
Pöttinger Terradisc 3001
Working width
3m Transport width 3m Number of discs 24 Disc diameter 580mm Disc spacing 125mm Power requirement 95hp (70.8kW) Weight (including roller) 2,080kg
Atrend in recent years has been to move away from the power harrow to unpowered mounted and trailing tillage equipment, with higher forward speeds and outputs that leave behind a well-cultivated firm seed bed. Recently, I got to check out an operation in New Zealand that has taken the plunge, largely ditching its power harrow in favour of one such machine; a Pöttinger Terradisc 3001 for cultivation. Stuart Deadman’s Totara Park farm milks cows on around 1,300 hectares north of Taupo in the central North Island. It runs an extensive re-grassing program, involving summer and winter cropping, as well as some conversion of forestry land in to pasture. Since the Terradisc was purchased early last year it has covered around 50ha and so far has proven itself more than capable in the property’s unique conditions. The light pumice soils found in this area aren’t the toughest to work up, but it does have unique challenges. Abrasive on soil engaging equipment, there’s only a minimal amount of topsoil over an infertile, yet free-draining pumice base. While Pöttinger suggests as little as 100hp (74.6kW) is required to pull the 3m Terradisc, for this test I had a John Deere 6210R hitched on the front; possibly overkill on the somewhat flat paddock we were in, but the operator says it is definitely required on some of the farm’s steeper country (and I was about to learn that maintaining a high forward speed is one of the keys to the success of this machine). The ground to be worked was winter crop that had been grazed off. While there was only a small amount of trash left on the surface, the ground was fairly compact after having cows on it. The plan was for one or two passes to be completed in order to create a seed bed for grass that was to be sown with a Hatzenbichler air seeder mounted on the back of the machine.
A LOT OF GROUND IN A DAY
The main frame is made of box section beams, while a sturdy headstock at the front couples the machine closely to the back of the tractor. Category two pins are used with a variety of holes for different mounting positions. Twenty-four scalloped discs of 580mm diameter are arranged at opposing angles in two rows. As each disc is bolted to the bearing housing with four bolts, eventual replacement should be simple while the maintenance-free, sealed twin race taper bearings also helps minimise downtime. Bearings run on a stub axle which, in turn, is mounted to a slim profile cast iron carrier arm with plenty of clearance for soil to prevent blocking. Carrier arms are then mounted in pairs to the main frame with a wide clamp, which will prevent sideways movement of the discs. The four rubber elements that are also cleverly squeezed into each clamp will take the shock away from the frame, allowing the disc to ride up if any large obstacles are struck. Operating at around 10km/h to 12km/h there’s certainly potential to cover a lot of ground in a day. When looking down at the machine from the cab of the tractor, you can see just what a great job the discs do, lifting the soil and breaking it up. Key to its success are the deflector plates down each side, which ensure the soil is contained within the width of the roller; this also guarantees a level surface. Set-up is really important. If the machine is trying to crab sideways or leave a ridge out one side, then it’s probably not set up level with one gang of discs cutting deeper than the other. Although the working width of the machine is 3m, due to the
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offset nature of the discs and the deflector plates, the actual overall width of the machine is closer to 3.3m. To ensure you can take it on the road and get it through gateways, the outer sections on either side can be manually folded. This is a good thing although I’m sure operators will find it a chore to continually fold and unfold them.
SPRING TINES AND ROLLER
Following behind the discs are an optional row of large spring tines. These are well worthwhile, although once again set-up is critical. Adjustments can be made using pins, with a series of holes for different heights and angles. The tines are set just deep enough to push a small amount of soil along in front, so they’ll break clods and level any hollows without blocking up the machine. Cleverly, the roller on the back of the machine is mounted in its own separate frame, which pivots off the main frame. Two hydraulic rams are used to lift the roller up and down, controlling the working depth of the discs. Five millimetre thick shims on a hinge system alongside the ram spears are a simple yet effective way of fine tuning the depth. The fact they’re on a hinge means they’re always connected to the machine and there’s little chance of them getting lost.
IN TOO DEEP
One problem I noticed with the Terradisc was due to its length when working on undulating ground; the discs will cut in too deep or come out of the ground as the machine rides over humps and through hollows. The hydraulic depth adjustment can be used if you’re quick on the controls to minimise this, although it is always going to be a problem. As for the actual roller on the back, Pöttinger offers a choice of five different roller combinations for the Terradisc, including a crumbler, packer ring and rubber roller, so there’s something to suit all conditions. The test machine was fitted with the most common packer ring roller. This uses deep steel packer rings, which do an excellent job of further breaking up soil in order to leave a firm corrugated seed bed that will promote water absorption. It has also proven ideal when the machine is fitted with a seeder such as this one; a drawbar fitted to the back by the owners is used to pull another roller to complete the onepass operation.
TWO PASSES
The Pöttinger Terradisc is an exceptionally well-built and thought out machine. Thanks to its simple nature, maintenance and running costs will remain low. There’s little doubt in my mind the concept of this machine is well suited to situations relevant in Australia and New Zealand. On the pumice country found at Totara Valley, the Terradisc is an ideal machine to work the thin layer of topsoil without disturbing the underlying pumice. Just two passes with the Terradisc alone left an excellent seed bed. Although there are a wide variety of soil conditions across the country I imagine in most situations a single pass after discing, ploughing or ripping would create a more than adequate seed bed.
1. The Pöttinger Terradisc compact disc harrow ticks all the boxes. 2. Discs on thin carrier arms are clamped to the main frame in pairs with rubber elements that allow movement and reduce shock on the frame 3. Forward speed is one of the keys to success in using the Pöttinger Terradisc 3001 4. Top rows of 580mm-diameter scalloped discs set at opposing angles aggressively cultivate the ground 5. A heavy duty steel roller on the back uses deep packer rings to leave a firm seed bed
Pluses
High output due to high forward speeds Simple and robust construction Low running costs Sealed maintenance-free bearings Hydraulically controlled working depth
Minuses
Length of the machine causes the discs to ride out of the ground in hollows Although the machine has a 3m working width, it still needs to be folded for transport
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