Great Plains’ SLD cultivator range was originally intended to fill the gap between the firm’s Solo and SL machines, offering a less aggressive disc action than the Solo, but a heavier duty, deeper working machine compared to the SL.
However, since its launch the SLD has gradually replaced the Solo as the manufacturer’s deep cultivation, pan-busting offering.
The SLD range is made up of six trailed machines, comprising two ridged machines with 2.8m and 3.3m working widths and four folding machines from 4.1m to 6m working widths.
To test the credentials of the SLD, we put it to work in some sticky, heavy Lincolnshire clay, working at a depth of about 200-250mm (8-10 inches). Muscle was provided by New Holland’s latest T8.420 AutoCommand tractor.
Sitting in the middle of the SLD range, our test machine was the SLD 460, suitable for tractors from 300hp to 650hp and with a working width of 4.6m.
Like the rest of the range, the 460 is based around a single beam chassis construction, featuring seven subsoiling legs with 600mm (24in) spacing.
In front of the legs is one row of discs which throws material one way, with another row of discs behind the legs which throws material the other way. Scalloped discs are 610mm (24in) in diameter and spaced at 250mm (10in) in the row – the rear discs overlap by half with the front discs to give an actual spacing of 125mm (5in).
Each disc is individually sprung to follow contours more effectively and protect the disc from strike. You could argue the discs are not as firmly held in place compared to fixed rubber mounted discs and quality of work could suffer.
However, we saw no evidence of this, with discs running true and coping with conditions well.
Having each row of discs throw one way, does mean a slightly less complicated construction than discs in an ‘X’ formation, whereby the front discs throw outwards and the rear discs throw inwards.
It also means angle adjustment of the discs can be made very simple via a screw mechanism on each corner of the machine, something fixed discs cannot do. To help adjust disc angle, a gauge on each corner gives you a guide.
This individual angle adjustment of the front and rear discs allows the machine to quickly adapt to changing conditions. A general rule of thumb is the front row of discs uses an aggressive angle to cultivate and incorporate trash while the rear set is set at a shallower angle for chopping and levelling.
We certainly found, in our conditions anyway, this arrangement left a good level finish and the machine pulled straight.
The subsoiling legs feature a hydraulic automatic reset system. Between 80 and 120 bar of trip pressure can be applied depending on conditions.
Standard leg fitment is the firm’s Pro Lift legs which can be fitted with a choice of wing widths; 250mm, 270mm (standard) or 300mm (10in, 10.6in or 12in).
A new option includes the fitting of low disturbance legs which slot in place of the standard legs, or as an alternative, a low disturbance leg frame can be fitted with leg spacings of 500mm (20in).
At the rear, a standard 700mm (28in) diameter DD roller is used for consolidation.
Working depth of the discs is set by shims on the roller’s and the drawbar’s lifting rams. The trick is to try and get the chassis parallel to the ground when working. A handy pole on the drawbar provides shim storage and a toolbox half-way down the chassis provides storage for tools and wearing parts.
Depth of legs are independently set via pin adjustment, with a choice of four holes. Working depth can be down to 300mm (12in).
To operate, the machine requires four, double acting hydraulic services. Thankfully, each is colour coded; red is main lift and lower, yellow is fold, green are legs and blue is the rear roller. This same colour coding also applies across Great Plains’ range.
Road mode requires two shims to be placed on the main lifting rams on the axle, on to which the weight of the machine can be rested. A tap is also used to lock out the hydraulic lifting ram on the drawbar.
We found the SLD to be very well behaved on the road and quite sturdy considering its loftyness.
For the machine’s set-up, once in the field, take out the transport shims and fold down the wings. When wings are folded flat, their respective hydraulics can be put into float. A valve on the machine holds the wings in position to maintain working quality, unless the ground undulates, at which point the wings are allowed to move.
Legs can then be folded down with their trip pressure built up to desired level, then hydraulics are put into neutral.
When working, the transport tyres want to be lifted up, right out of the way to allow the machine to work properly.
The SLD is fitted with a category four drawbar but category three or five can be specified as options, as can a ball and spoon drawbar.
Other options include a rear drawbar which is capable of towing a Cultipress type machine, a Stocks Turbojet kit with the ability to apply OSR for example, and pneumatic brakes.
Given the tough conditions, the SLD performed well, leaving a neat and level finish.
Operation was fairly straight forward – once you have set it up, there is only really raise and lower to look after. Disc angle aggressiveness is particularly useful, allowing you to quickly adapt to changing conditions.
There is no denying its construction looks fairly substantial, giving you lots of confidence as to how much it can handle.
While it does take a bit of pulling, at least you can be safe in the knowledge it is doing a lot of work.