Canadian monster drill Clean Seed offers new level of seed accuracy

CX-6 Smart Seeder. Photo credit: Clean Seed

Clean Seed, a Canadian outfit with a penchant for meticulous drilling precision, recently unveiled a maiden seeder promising never-seen-before levels of accuracy from a high-output cereal planter.

And its vital statistics make for some eyebrow-lifting reading. It carries 360 motors, can drill 6 different products at 3 different depths, weighs 35t and the full package will cost you in the region of US$600,004.

In return, you get some of the most sophisticated drilling technology ever imagined, including turn compensation, overlap protection, individual point shut-off and a variable application rate at every opener.

It relies heavily on 6 metering units that sit on top of each row unit so individual legs can sow a different ration of seeds and fertilisers at the same time.

In fact, the agronomic permutations are practically limitless and it gives farmers and agronomists the license to be as creative as they like with their inputs, tweaking drilling rates and application maps in almost infinite detail.

New designs

The 17 different patents serve as a stark illustration of the CX-6’s novelty value and, remarkably, it has been transformed from drawing board sketches to the real deal in just 5 years.

Its design has been heavily shaped by the creative minds of a group of Canadian farmers keen to push the boundaries of agronomics, but hobbled by the inconsistent seed distribution and limited adjustments offered by regular air seeders.

CX-6 Smart Seeder. Photo credit: Clean Seed

The way pneumatic machines meter seed and fire it through an air stream is far quicker than the old-but-reliable box drill, but air also causes seed to bunch, surge and bounce in the trench.

No good, then, if you wish to sow plants with extreme precision and mix exotic-sounding cocktails of fertilisers to go with them. So, with an assembled team of farmers and designers, the company decided to embark on its own drill-building mission.

To fund the project, Clean Seed gathered a healthy $80,000 investment from a group of 10 progressive farmers in Canada and by 2013 the first fruits of the development – the 6-product digital metering system and triple-shot opener – were displayed at Canada’s Farm Progress Show.

Another financing push filled the coffers enough to continue development and a full prototype drill was unveiled in 2014. The first commercial unit then debuted last year and several production machines have been working flat-out across Canada through last spring.

Metering is the key

Farmers feel like they’re very accurate because when a field is drilled it has used their precalculated quantity of product, according to Clean Seed’s Noel Lempriere. However, if you go down to a square-foot level, you will likely find areas of the field where the rate is wildly off what you wanted.

The answer, according to the designers, lies in electric metering which takes away the distribution problems of air seeders that meter the inputs at the main tank, which are usually a long way through a tangle of plastic tubes from the coulter tip.

The Smart Seeder’s pipework runs in the normal manner from the seed and fertiliser tanks to the row units; nothing unusual in that. However, it feeds a bank of 6 mug-sized pre-holding stations that sit on top of each row assembly.

CX-6 Smart Seeder. Photo credit: Clean Seed

These metering mugs are kept fully-stocked with seed and/or fertiliser and operate independently of their neighbours so, rather than applying generic blends of fertiliser like most air drills, farmers can be as creative as they like with their inputs because they are mixed as they drop down the opener chute.

Each of the 360 automotive-grade electric metering units is controlled wirelessly from a tablet in the tractor cab and they are powered by an onboard 24V AC circuit kept fully juiced by two batteries and an alternator.

Amazingly, they sap just 1,900W which, as a comparison, is less than it takes to run a regular hairdryer. Foam rollers grab the seed or granule from the mug and drop it by gravity into one of 3 stationary funnels, just like an old box drill.

Photo credit: Clean Seed

To change which of the 3 funnels the material is dropped into (and therefore which of the coulter outlets it falls through) there is a threaded rod that can be slid 75mm (3in) left or right, while there’s a deeper central outlet for fertiliser.

The flotation tyres on each wing are also fitted with speed sensors, so as the rig negotiates an obstacle it will compensate for the turn by decreasing the drilling rate at the innermost row and gradually increasing it to the outer one.

Triple-shot opener

The openers are built to move just enough soil to encourage rapid root development without getting too much surface disturbance.

A big 610mm (24in) saw-tooth vertical disc coulter bites through the trash and is trailed closely by a 3-part opener that delivers the seed and fertiliser.

The latter is typically dropped about 60mm (2.4in) deep – well below the seed – and is covered by 50mm (2in) of soil. The seed is then placed on the loose portion of soil, through any one of the 3 apertures, and a closing wheel (rather than a packer) throws over a blanket of dirt to finish the job.

Triple shot opener. Photo credit: Clean Seed

That gives farmers the option of drilling paired rows or, often in the case of Canadian farmers, throwing down stacks of urea between crop rows to get rape crops growing.

Having a fairly loose column of earth encourages quicker root development than those drills that work by scratching out a stiff channel and ramming soil back over the seed to close the slot, says Clean Seed.

In turn, that allows water to permeate through the surface and also climb wick-like from underneath, so users should see pretty quick emergence compared with a conventional system.

Why 6 products?

It might seem a little overkill to have 6 separate tanks along with the associated pipes and metering units, but it allows buyers to make very specific blends of N, P, K and S at each individual opener.

There’s also the option of playing about with seed varieties. Research into this particular area is pretty thin on the ground at the minute because there has not been the tools to apply it, so the CX-6 opens the door to a whole new world of intercropping and multivariety drilling.

6-tank set-up

The individual row units are fed by a medley of 6 separate hoppers that have been carefully proportioned so each one empties at almost the same time.

Total capacity is 17,600-litres (622cu ft), which is fairly modest by North American prairie standards where the big boys often have up to 35,000-litres (1,236cu ft) at their disposal.

Individual tanks range in size from 1,450-litres to 5,285-litres (50-187cu ft) but, provided each hopper is filled with the most suitable input, the drill should still be able to outlast a lot of its larger foe on each load, which keeps downtime to a minimum.

Each chamber uses its own Clean-Seed-built venturi system to shift the material to a vacuum meter. Pressure differential is the key here, so it applies -0.1bar (-2psi) in the tank to encourage the product to flow.

Row unit close-up. Photo credit: Clean Seed

There are also 2 fixed-rpm fans on the front of the drill that run at different speeds. The first is for the venturi system and spins at relatively slow 5,200rpm to shift the high volume of material from the tank. A second fan acts as a boost system by whizzing round at 6,300rpm and at high pressure to keep the lines clear.

The hoses that lead to each opener are fairly run-of-the-mill. The difference is that, while an air seeder fires material at huge velocities that cause the seed to have a sandblasting effect on the hose wall, the Smart Seeder sends them down at a comparatively leisurely pace.

That low velocity could also lead to marginal improvements in germination rates because of fewer microfractures in the seed.

Quick filling on the go

Frequent half-hour, stop-and-go fill-ups have long been the choke point in high-speed drilling operations, so Clean Seed has developed a hook-on nurse cart that mirrors the tank layout of the main drill.

The idea is to leave it in the field roughly where the drill is expected to run out of seed. A winch cable on the back of the CX-6 means the driver simply reverses within 5m (6.5ft) of the cart and then reels it in until it’s latched on the back.

Once onboard, the rig can carry on seeding while the tanks are filled on the fly. Initiating the transfer is done wirelessly from the cab and the whole process takes 23 mins, after which the cart can be dumped on the headland and collected by a waiting helper.

Processing power

A machine of such sophistication requires powerful software to control its operations.

The in-house developed Seed Sync system runs off a Windows tablet and information is transmitted wirelessly to each of the metering units via Bluetooth antennas. This avoids the need for a girthy harness of cables running from the cab to the coulters.

Tablet control. Photo credit: Clean Seed

As well as offering full control of flat-rate inputs, it can also process variable-rate application maps. However, the major limitation at the minute is the resolution to which agronomists and farmers can concoct the seed and fertiliser maps, rather than the ability of the drill to apply them.