While precision farming has become part of daily life on many farms, there might still be some big steps to make – one of which could be precision drilling of cereal crops. Geoff Ashcroft spoke to drill manufacturers about the technology.
When it comes to precision farming, new technology emerges on an almost constant basis. Yet despite recent advances in machine control systems, there are still many untapped opportunities to boost efficiency. In the short-term, most technology has focused on more targeted and managed applications of sprays and fertilisers.
But we have still to see mainstream cereal drilling equipment take up precision farming technology in quite the same way as their spreading and spraying counterparts.
Precision seeding of cereals is not a new development but the advent of more advanced precision farming mechanisms and sophisticated electronic controls might just make it a more viable option in the near future.
Some readers may recall precision seeding firm Stanhay Webb channelling some of its experience in precision seeding of vegetable crops towards wheat crop trials over 15 years ago.
Using a Singulair drill, and latterly seeding units from its Dart, the firm worked with rates from 20-60 seeds/sq.m. Preliminary findings were fewer plants spaced evenly encouraged more vigorous growth, with deeper rooting and a considerable increase in tillering.
Even at 20 plants/sq.m, wheat was found to produce about 30 tillers per plant – considerably more than the six to eight still found on traditionally drilled crops.
Currently German manufacturer Horsch is perhaps the closest to commercialising precise placement of cereal seeds, following a protracted gestation period for its singulation unit.
The add-on device – Pronto drills need one for each TurboDisc coulter – is essentially a secondary metering system which singles out pre-metered seeds and places them at a prescribed spacing down the row.
Seeds are delivered to the singulation unit from the drill’s standard seed metering rolls and air delivery system. Once inside the row-specific metering unit, the seed flow follows a circular path through the device where the grains increase in speed and move to the outer part of the metering disc. One is then selected for the drop tube.
All remaining grain seeds are transported back to the starting point and small heaps and gaps in the volumetric seed flow can be minimised.
Horsch says the single grain metering unit is able sow a single grain twice per second, resulting in a seed density of 240 grains per sq.m at 12kph, with a row spacing of 15cm.
The speed of the disc changes according to seed size and desired spacing.
Having been kicked around the German countryside for the last 10 years, it looks likely a handful of units could come to the UK for evaluation next year.
Stephen Burcham, of Horsch UK, says: “Singulation allows precise seed spacing without impacting on forward speeds. It has many advantages, not just seed saving.
“If multiple seeds fall in one area, plant growth will be compromised due to competition for light, space, nutrients and water. Fewer seeds will create stronger plants with better root structures. And that means better resistance to stress and drought. And with more tillers, there could be a nominal 2-3% yield increase.”
At this stage, Mr Burcham sees the singulation device as a means to increase seed spacing accuracy down the row, rather than one which can deliver individual row control to eliminate overlaps.
“Airflow management will be the key to handling individual row control,” he adds.
Big strides have also been made recently with precision drill technology. And many growers have been able to take advantage of individual row control with maize and sugar beet.
The introduction of individual electric seed metering systems with GPS control for on precision seeders has led to a reduction in overlaps and seed savings for many maize and sugar beet growers. And reducing plant competition affords more light, space and nutrient availability for growing plants.
There are a handful of manufacturers which are making progress in using their precision seeders, with minimal modifications, to sow crops such as oilseed rape.
Kverneland product manager Graham Owen says: “With GEOcontrol, the success of our Optima and Monopill precision seeders has proved it can be done.
“What we are looking to do next is to refine the technology so it can be applied to mainstream grain drills.
“With grain drills, our GEO technology is well-proven for executing auto stop-start on headlands, and for controlling half-width shut-off on drills with wider working widths. But when you consider the way pneumatic grain drills operate, and at 15, 18 and even 20kph forward speeds, making the move to individual row control poses many different challenges.”
In addition to airflow management, he says seed hopper sizes are also a key consideration.
“If we can lower seed rates as a result, then this should help to overcome the seed hopper volumes currently required for planting cereal crops.”
While half-width shut-off goes some way to reducing seed waste and overlaps, Pottinger has made progress with its intelligent distribution system (IDS) and precision combi seeding (PCS) with the Aerosem range of pneumatic drills.
PCS is a mechanical single-seed unit, which is an add-on for the conventional drill. It adds functionality and enables the Aerosem to extend its repertoire with maize in addition to cereals, and grain and fertiliser.
IDS, however, delivers automatic seed flow reduction with the help of electronic seed metering. It has been developed primarily for seed management with tramlines.
Shaun Groom, Pottinger UK’s general manager, says: “Where seeds from tramline outlets are usually redistributed towards other coulters, IDS can reduce seed rates by up to 6% to compensate for a change in the number of coulters being fed.
“It is a positive step towards greater precision with grain drills.”
The next step is likely to be GPS control of individual rows, although managing airflow will be a considerable hurdle to overcome, he adds.
“When it comes to switching off coulters to manage overlaps, for example, it will be difficult to handle rapid changes in airflow requirement.
“It’s not easy to wind back the fan speed to maintain seed distribution over fewer rows, and it becomes even harder to achieve at high forward speeds.
“And it will be equally as difficult to build air, when you pull back into a bout and you need to progressively switch on 24 rows over a three-metre working width.”
Lemken is making small but useful steps into precision seeding with its Azurit, and while primarily for single seeds such as maize, the drill can also be used for oilseed rape establishment.
When it comes to grain drill technology, the firm’s Solitair 12-drill range does deal with overlaps perhaps more successfully than most. And it is due to the use of eight metering systems, offering eight drill sections across the working width.
Those working widths can be eight, nine, 10 and 12m, with the widest version getting eight 1.5m sections.
In its most basic form, metering units are switched on and off mechanically. But as an option, electro-hydraulic control can be achieved form the cab using the Solitair controller.
Lemken UK’s general manager Paul Creasy says: “The drill is IsoBus-compatible and with Solitronic and GPS, is able to carry out automatic section control and stop/start on headlands.
“Section control has been made easier to manage by returning seed to the tank. It’s small steps but our customers tell us they are saving seed, which suggests we’re moving drill technology in a worthwhile direction.”