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LAMMA 2021

LAMMA 2021

ScanStone separator has starring role in soil preparation

Designed to cope with a wide variety of soils, one large-scale East Anglian root crop grower has invested in the latest stone separators. Jane Carley finds out how the new machines are performing.

A pair of ScanStone Eco Star separators – part of a fleet of six – prepare ground in Suffolk for Tompsett Growers’ parsnip crop.
A pair of ScanStone Eco Star separators – part of a fleet of six – prepare ground in Suffolk for Tompsett Growers’ parsnip crop.

Growing parsnips and carrots on 1,250 hectares of rented land in East Anglia, Tompsett Growers needs productive, tough soil preparation equipment, working flat out from January to April. After a successful first season with ScanStone EcoStar separators last year, the company added a further two machines for 2020, bringing the total to six, with a pair of older machines from another brand as back-up.


Tompsett Growers manager Jason Ambrose explains: “We tend to work two or three separators together, so a fleet of six means we can have two gangs preparing land in different areas, or working together on carrots and parsnips to get through the workload.”


The choice of a star separator was based on the varied soils cropped by Tompsett Growers across Norfolk, Suffolk and Cambridgeshire. “Some land can be stiffer, so there are clods as well as stones to contend with, and an all-web machine can be slow in these conditions. A star system goes well if you run it right – it is important to keep the separator full. Big web machines may offer a high capacity on the right land, but these are quicker overall.”

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Jason Ambrose

Jason Ambrose, Norfolk Growers manager, oversees growing operations.


Roots are generally grown on different fields as part of six-year rotation on the same estates each year. Certain farms can also be tough on machines, with hilly land and plenty of flints, so a durable design and build was also a priority.


“We have previously used outside contractors for separation, who had older machines, and when they closed their business, we decided to purchase our own,” explains Mr Ambrose. “We can manage the workload better, and although they represent a significant investment, they can be going for five or six months of the year on carrots, so we get plenty of work out of them.”


While it is mainly a spring operation, Tompsett Growers also plants 40ha of overwintered parsnips, so the separators are back in use in November. They are part of a soil preparation system which starts with subsoiling down to 40cm, followed by ridging up and separation, then bed forming and finally sowing carrot or parsnip seed with a precision drill, so good workrates and avoiding downtime are crucial.

GPS steering

GPS steering on the separator helps to keep in the row on side slopes and ensures accurate rows for following machines.


Mr Ambrose comments that the competitive price offered by ScanStone, plus the establishment of a depot at nearby Lakenheath, Suffolk, by the Scottish company, were a major attraction. A demonstration showed that the machine itself also fitted the bill.


“There is a high level of automation of depth control, self-levelling and self-centring steering but you can also easily make adjustments for the conditions, such as controlling the hydraulic front discs independently in stony soils to release a trapped stone.”


The new EcoStars are fitted with GPS steering which works with the tractor’s auto steer to help keep the separator in-line, especially on hills where the slope can lead to crabbing or where it is running in the stone trench and can slip. “It makes the operation more efficient as the operator is not having to constantly correct the separator; it also produces a better ridge for following machines. There is less fatigue for the operator and he can focus on the job in hand.”


Design features include an open front digger web, with hydraulically controlled front discs allowing the pressure to be set by the operator to float with the contours of the ground, improving soil flow on hills whether working up or downhill.

Six rows of stars

Six rows of stars replace the middle web to tackle more varied soils with clod as well as stones.


Mr Ambrose adds; “Automatic levelling ensures that soil is spread evenly over the machine when separating on undulating ground to maintain an even bed formation.


“A headland management system lifts the discs, stops the scrubber web, conveyor web and auto-levelling and reverses the conveyor at a touch of a button on the control box to ease turns at the end of a row, lowering and re-engaging as the machine re-enters the next row.”


Air brakes have been specified and the drawbar and axle are also damped to improve safety and comfort on the extensive road travel required between sites.


Operator Andy Rusking says that he finds the EcoStar very easy to use and maintain. “Although the operation is largely automated, joysticks on the control box allow me to adjust the conveyor, lift or lower the rear web, alter the digging share depth or the pressure of the scrubber web or reverse it and fine tune the body levelling manually. It is very quiet in operation due to the belt drive, which also makes it cleaner to maintain than a chain-driven implement.”

Control box

The can-bus control box features proportional joysticks to fine tune automated settings and displays information about web and disc position plus headland management engagement.


An hour counter on the control box also provides an alert for greasing the pto, while other service intervals are clearly labelled on the machine. Workrates depend on the soil texture, the stiffer soils in Suffolk taking it down to 0.4ha/hr and using 13.3 litres/hr of diesel.


Mr Ambrose comments that the EcoStars stood up well to the work in the first season, ahead of the customary winter strip down and service in the company’s own workshop. Operators also maintain the machines so have a good idea of the parts that will be needed so they can be ordered from ScanStone Lakenheath in good time. Tompsett Growers also keeps a stock of parts such as digger webs in case in-season repairs are needed.


“The machines covered 170ha each last year; the stars last well with just the outer two rows, which are prone to damage, needing replacement, while the digger web and front rollers also needed changing. We also refurbished the cross-conveyor drive – our new operator reported that they are good machines to work on, with the components easier to access than some brands.”

Soil preparation

The company grows 40ha of overwintered parsnips for harvest in spring, so the soil preparation operation also takes place in November.


Carbon fibre belt drive also cuts downtime and costs, and after a few teething problems where belts were not lined up, has since proved reliable. Tough conditions can take their toll on parts, and the wet start to the 2020 season has put extra wear on digger webs, he notes.


Mr Ambrose suggests that as the wearing parts are changed regularly, only the frame and chassis is subject to anno domini, so separators can be kept for up to 10 years.


With a team of 25 full-time operators, Tompsett Growers also relies on owner-drivers to supply tractor power and labour at peak periods, with 200hp up front described as ‘more than adequate’. “You do need to be able to keep the revs up slightly, rather than running at tick-over, to keep the oil flow going to the GPS steering on the separator - 200rpm is fine (pto speed).”


Mr Ambrose comments; “Parsnips are harvested 11 months of the year, and we have to be able to keep the packhouse, of which our parent company is a partner, supplied with produce. So reliable and versatile equipment is key.”

Separator specification

Separator specification
  • Model: ScanStone EcoStar
  • Number of webs: Two
  • Star rows: Six
  • Power requirement: 150-180hp
  • Length: 7.74m
  • Web width: 1.54m/1.74m
  • Steering angle of axle: 34 degrees
  • Transport width: 2.57m/2.77m
  • Weight: 6,500kg
  • Hydraulic flow requirement: 30-40l/min
  • Road lighting: LED
  • Tyres: 375/80 R20
  • Options: 24 inch wheels, auto-greasing, stone box, stone elevator
  • Retail price: £65,725
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