Test: Pottinger Terrasem C6

By: Brent Lilley, Photography by: Brent Lilley

Pottinger Terrasem C6 Double disc coulters use a slightly-leading disc to open a furrow and the seed is dropped between the two discs Pottinger Terrasem C6
Pottinger Terrasem C6 Coulters are mounted individually to the frame with a parallel linkage to allow them to follow the contours of the ground being drilled Pottinger Terrasem C6
Pottinger Terrasem C6 The big 305hp Case on the front had little problem pulling the 6m Terrasem drill Pottinger Terrasem C6
Pottinger Terrasem C6 Press wheels following the coulters and tine harrows are used to cover and consolidate the seed furrow Pottinger Terrasem C6
Pottinger Terrasem C6 A large rectangular hopper has a 3000L capacity Pottinger Terrasem C6
Pottinger Terrasem C6 A computer-controlled electronic metering system uses a ground speed radar to acurately measure seed out in to the main tube to the distribution head Pottinger Terrasem C6
Pottinger Terrasem C6 Two rows of 510mm diameter scalloped discs at the front of the drill are adjustable from the cab and work at opposing angles to cultivate the soil Pottinger Terrasem C6
Pottinger Terrasem C6 The twelve-wide 425/55 R17 tyres across the width of the drill firm up the seedbed before the coulters Pottinger Terrasem C6
Pottinger Terrasem C6 At least four hydraulic remote valves on the tractor are required and there are still taps on the drill that need to be changed Pottinger Terrasem C6
Pottinger Terrasem C6 A straightforward and easy-to-use control box with a backlit colour display screen Pottinger Terrasem C6

A drill is a huge investment for any operation, but this month we’ve tested one that offers larger-scale arable farmers some big savings thanks to its huge coverage.

Test: Pottinger Terrasem C6
Less passes, more kicks

Some form of mechanical device able to plant multiple seeds in multiple rows, simultaneously, has been around for more than 2000 years, starting with the multi-tube iron seed drills in China. I can only imagine what a quantum leap this device would have been for the farmer of the day, who'd previously planted each seed by hand. Equally, in modern times, a drill that will cut down the number of cultivation passes before drilling, and one featuring time- and seed-saving innovations, could also be considered a quantum leap in the quest for efficiencies and increased productivity.

In August I headed to the heartland of New Zealand's arable industry, mid-Canterbury, to witness a drill promising to deliver all this. The Pottinger Terrasem C6 drill, was sowing processing peas on Keith Wild's property near Chertsey. In front was a 305hp Case Magnum, which had no problem pulling the drill at the recommended 10-12kph and, with six metres of coverage, gives an impressive output of around three hectares per hour.

The Pottinger Terrasem is sold and serviced by Cochranes, Canterbury and imported by Origin Agroup. South Island sales manager Darryl Chambers organised the test and was on hand to run me through the finer details and answer any of my queries.


The Pottinger Terrasem disc drill is designed as a trailing cultivator drill in order to cut down the number of passes required when establishing crops in a cultivated seedbed. The drill works in three sections — tillage equipment at the front, followed by a packer roller, followed by the disc coulters for sowing. These are all mounted to a solid and stable box-section frame in the centre. Wings are used on either side of the mainframe in each section to give the machine a six-metre working width, while also allowing it to fold up to a safe travel width of three metres. Over-width markers are fitted to the front and rear, along with a road lighting package.

At the front, a telescopic drawbar allows the drill to be used on tractors with duals, without compromising manoeuvrability. Linkage bar mounts on the lower link arms of the tractor, with a heavy-duty rotary joint to the drawbar, allow for impressive turns up to 90 degrees. This drill was fitted with bout marker arms, although they weren't in use as the Case was running a Trimble GPS guidance and auto-steering setup.

Tillage equipment

The tillage equipment at the front end of the drill uses two gangs of 510mm scalloped discs at opposing angles to loosen and break up the soil while incorporating trash. The discs are in sets of two and are mounted to a hefty length of box section, with four rubber blocks allowing each individual set of discs to lift over rocks and obstacles. The depth of the front gang can be set independently of the second gang, while hydraulic rams are used to lift both gangs out of work and set the overall depth — a scale that can be seen from the cab of the tractor allows the depth of the discs to be adjusted on the fly.

Behind the discs is a single row of spring tines with an adjustable depth to help leave a smooth and level seedbed. Steel guide plates on the outside edges of the discs keep the soil in, preventing it from spewing out onto the previous run.

The tillage equipment on the Terrasem was doing an impressive job. The ground being sown had been ploughed and cultivated once, but there were still some decent-sized clods on the surface, which I imagine would require at least one or two more passes with a cultivator or harrow and roller to create a seedbed for a conventional drill.

Packer roller

A tyre packer roller, after the tillage equipment and before the seed coulters, is used to consolidate the seedbed before drilling, using twelve 425/55 R17 tyres arranged in three sections. This is probably the widest packer tyre I have come across on a drill and it was doing an excellent job. When the machine is working and lifted at the headland, the tillage equipment seed coulters are raised up, while the packer tyres remain in the same position. As the weight of the drill is spread over the entire width of the twelve tyres rotating independently, there will be minimal compaction and scuffing of the headland when turning.

When the outer wings, featuring three tyres on each side, are folded up for road travel it leaves six in the centre section. Of these, the centre two are hydraulically lifted automatically. This greatly improves the stability of the drill and cuts down on tyre wear. The tyres are all mounted to the frame individually and slightly staggered, which should make it easier to get one out if you happen to get a puncture.

Seed hopper

A decent-sized seed hopper mounts longitudinally down the length of the machine and, at 3000 litres, has plenty of capacity to keep you drilling for longer between fills, even when drilling larger seeds at higher rates. There is a dust- and rain-proof tarpaulin cover that rolls clear of the hoppers, opening for full access, while a ladder from the left-hand side to the platform at the front of the hopper gives safe and stable access for the operator. Inside the hopper, a steel removable mesh prevents larger objects from getting into the metering mechanism and a seed-level indicator is located low under the mesh to allow drilling to continue down to a very low level.

The long rectangular shape of the hopper allows for the possibility of filling direct from a bucket, bulk bags or an auger. The drill on the day was being loaded with another Case IH tractor using a loader from Keith Wild's red fleet and although it is possible to load the drill with a tractor, it was awkward and the drill was jack-knifed. A telehandler would make the job easier.

Metering system

A single electronically-controlled metering system is used at the bottom of the hopper, dropping the seed directly into the main tube to the distribution head. The speed of the metering wheel is computer controlled and the ground speed is taken from a radar mounted at the front of the drill. With a coarse and fine metering wheel that is easily changed without tools, and a gearbox with interchangeable gears, the Terrasem has infinitely variable drilling rates, from as low one kilogram right up to 350kg. An outlet slide next to the metering unit is handy to empty any leftover seed out of the hopper.

Although the drill was calibrated when we got there, Chambers was happy to run me through the straightforward process. A flap on the metering unit, with a handy sensor to prevent it accidently being left open when you go drilling, is opened to divert seed into a collection container. A calibration sequence is selected on the control box in the cab of the tractor, which runs a measured amount of seed out. Once this is weighed, the amount is entered into the control box and it will adjust the speed accordingly. The process can be completed again to check. This is incredibly simple compared to the pages of tables and calculations that I remember in the past.

Fan and distribution head

A hydraulically-driven fan is situated at the front of the drill, out of the dust. The speed is adjustable to ensure there is a high volume of air to pick up the seed and carry it through the distribution head and on to the coulters without damaging it. The fan was noticeably quiet when compared to some larger air seeders I've experienced overseas.

The distribution head is at the rear of the machine, above the centre section with 48 outlets. I believe this had two stand-out features incorporated into it, the first being a half-width shut, using a hydraulic ram to close off half of the outlets to one side of the drill. This, when combined with the metering unit that will halve the metered rate, will lead to savings when drilling out triangles or narrow finishing strips.

The second feature to impress me was a tramlining kit that shuts off up to six rows over two tramlines on the required run. Unlike many drills, this uses an electronic servo motor to divert the seed from the tramline rows back into the riser tube, while the metering unit once again reduces the seed rate accordingly, leading to seed cost savings.


At the rear, there are 48 double disc coulters, spaced across the six-metre width of the machine in two staggered rows to give row spacing of 125 mm (or five inches). The two discs are identical and have a 380mm diameter. They are mounted in a V-shape with one disc slightly leading the other, opening up a slot into which the seed is dropped. The discs are followed by a wide-press wheel that guides the depth of the coulter, ensuring a uniform depth and adequate soil contact to the seed.

The pressure on the individual coulter is hydraulically adjustable between 40 and 120kg, while the depth via the press wheels is adjusted centrally with a ratchet adjuster. The coulters are once again mounted to a box section coulter rail, with four rubber blocks allowing for individual movement. The coulter rail mounts to the back of the tyre packer, with a four-point parallel linkage ensuring the coulter follows the contours of the ground while maintaining the set down pressure. Coulters are lifted hydraulically from the cab of the tractor. This system works well on a drill this wide as, regardless of the ground contour, the individual coulters remain in contact with the ground. This was evident on the uneven runs left from the previous run of the plough where the drill coulter followed in a wave pattern.


The in-cab control box for this machine is an ISOBUS compatible ARTIS box, featuring a back-lit colour screen and a membrane panel with the buttons to control it. This control box was simple to use, with a customisable home screen displaying the forward speed, fan speed, seed rate, hopper level and the area covered. Several pages can be scrolled through on the screen to change settings and select the calibration sequence.

The rest of the hydraulic functions on the drill, including the fan drive, headland lift, cultivating depth, folding, track markers and coulter pressure, are controlled through the tractor hydraulics. One of the few faults I have with this drill lie is, with six hydraulic functions to control, you require an absolute minimum of four remotes on the tractor to get the best out of the drill and even then you will need to get out to turn taps for folding, coulter pressure adjustment and track markers. Pottinger does have a solution for this, though, which is its ARTIS+ control box, featuring all the ARTIS box controls along with full control over all the hydraulic functions running through a power beyond coupling on the tractor.


For me, this drill largely ticks all the boxes for those operating in a large arable situation with a lot of acres to cover. A drill like this is a huge investment for any farming operation, although there are some massive gains and savings to be made cutting down the number of cultivating passes over a field before sowing. I imagine this drill could easily cut out at least one or two passes in most situations. Also, the half-width and tramlining shut-offs, recycling the seed back into the system while lowering the seed rate, will lead to impressive savings on seed costs. As usual, Origin Agroup offers a range of Pottinger seed drills for those of you with a few less acres to cover and a smaller budget.

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