Meeting unique demands with home-made drill

Article taken from the Farmers Guardian, written by Howard Walsh

When you cannot find a machine with the specification you want ‘off the shelf’, one solution is to build it yourself.

This is what North Yorkshire farmer Neil Welburn did – together with help from local fabricators and engineers – to create a rapeseed drilling rig with all running adjustments controllable from the tractor cab.

The 2.68-metre wide combination drill has now been used for a number of seasons on the Welburns’ Cross Hill Farm, Balne, where it has been utilised to establish their 40.04 heactares (100 acres) or so of winter OSR, plus about another 81ha (200 acres) for other growers locally.

Neil Welburn, wife Deirdre, son Chris and daughter Claire farm about 243ha (600 acres) in total, most of it rented.  And as Claire tends to do much of the drilling, she wanted to be able to make on-the-move adjustments from the cab to cope with different soil and surface conditions.  Importantly, she also wanted to be able to reset the cumbersome subsoiler legs easily in the event of a shear-bolt break.

The land they farm varies from blowing sand to almost unfarmable clay although OSR tends to be grown on the heavier, rather than sandy, soil.

Mr Welburn says: “As it is for a lot of people, black-grass is an ongoing problem and, whatever we built, it was important it did not make the problem any worse, for example by dispersing weed seeds to lower levels.

“We also wanted to be able to drop off the rape seeder element quickly, in order to then use the main cultivation element for min-till operations on bean and rape stubbles before drilling wheat.

“There was nothing on the market which really ticked all these boxes, which is why we set about making one – and it was all pretty much out of my head, with no detailed design plan.”

The machine is based on the back of what began as a three-leg Russell Farmrite subsoiler, although there is not much of the original implement to see now.  And having been given two good second-hand hydraulic rams, this was also an opportunity for Mr Welburn to put them to good use.


Five new legs were fabricated by Dean Foster at Agriweld, Driffield, to a design which would lift and loosen soil without either bringing up black-grass seed from lower levels or taking surface soil and seed back down.

And he incorporated a reset system which makes shear-bolt replacement an easier task for Claire – although breakages are few.  The top of the leg is formed into a claw which engages over the extra-long shear bolt.  If a leg does break back and is then pulled back into place, precise realignment if necessary, which is done by simply adjusting a bolt, secured by a lock-nut.  The unbroken length of shear-bolt is then pushed further in and secured by a spring clip.

Legs are at 500mm (20in) spacings, but Mr Welburn believes this is far too wide to be dropping in rapeseed.  As such, a surface tilth is created by two rows of scalloped discs, and then the 12 seed slots at 240mm (9in) spacing are created by DD packer rings.

The seeder unit itself comprises two Stock hoppers delivering, via 12 tubes, to the outlets welded onto a spring-pressured bar, also carrying spring tines to cover seed.  In practice, the seed free falls about 70mm (3in).

Once rape is drilled, a Cambridge roller is used as a separate operation when ground conditions are appropriate.

Whether used as the rape drill or as a stand-alone cultivation implement, the home-built rig offers separate hydraulic adjustment of the discs and the DD rings from the tractor cab.

Mr Welburn says: “In wet conditions we might leift the discs out of work completely, as well as the adjustment of the DD rings within the frame, we can of course take some weight on the tractor linkage if necessary.”

Running parallel with the discs on one side of the implement is a simple board to eliminate any ridge which might be created by the outward angled disc on the end of the back row.

When drilling rape, a simple radar unit set at precisely 45-degrees to ground level monitors forward speed – normally from 4-8kph.  Mounted at the back, it is unaffected by soil movement and this, together with low cost GPS (accurate to 100mm, or 4in) and the tractor’s own instruments, enable an accurate idea of true forward speed to be used.

Seed rate is variable and adjustable from the cab, and at whatever rate it is set, this is maintained proportional to forward speed.  Initial calibration is done by catching the seed from each individual outlet tube.

The combination is mounted on a 187hp New Holland 8770 with front weights to counterbalance the circa two tonne weight of the machine.  Although almost 20 years old, the comparatively low hours tractor is always’s Claire’s choice.  It is equipped with Trimble 750 guidance and New Holland’s entry-level EZ-Steer automatic steering system.


Both Mr Welburn and his agronomist Simon Vaux are adamant they key to success with oilseed rape is not necessarily the calendar date of drilling, but rather the timing.  This, the agronomist says, means taking into account the weather conditions and the type and state of soil.  And where black-grass is a problem, cultivation technique should aim to keep the weed issue where it is – on the surface.

Mr Vaux says:  “Ideally, you want to see a bow-wave in from of the subsoiler legs, but not vigorous mixing.  This will achieve the required loosening and aeration, leaving following cultivator elements to create the tilth.”

The target seed rate at Cross Hill Farm is 30-40 seeds per linear metre (9-12 per foot) with hybrids and 50-60 per metre (15-18 per foot) with conventional varieties.

On a trial basis on a few fields, frost-susceptible companion crops of various legumes are being assessed which allow the rape plants to get a good start, helping rooting by mitigating any compaction, helping subdue weed competition and also contributing to soil nitrogen.


05 June 2015

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