GPS spreaders: what’s on the market?

Plenty of sprayers come fitted with GPS-guided boom section on-off control systems these days, but now operators can get similar systems on fertiliser spreaders.

With the introduction of Kuhn’s Vari Spread for the 2013 season and Auto-Switch for the KRM-Bogballe spreaders, most of the leading suppliers can now offer auto width adjustment on their top-spec machines.

They join Kverneland’s GEOspread software, which is operated through the IsoMatch Tellus isobus terminal for Vicon Rotaflow and Accord Exacta spreaders, and Amazone’s GPS-Switch system, which gives variable width working on ZA-M mounted and – uniquely – ZG-B trailed spreaders.

In addition to altering the spread width progressively when approaching headlands at an angle or where tramlines converge, these advanced control systems will also stop and start spreading at the appropriate point when approaching and departing headlands.

This function alone is provided by Stop & Go system for Sulky X series broadcasters from Reco, with limited automatic width adjustment provided by the border spreading mechanism on one side of the machine.

Auto headland on-off is also available with the Opti Point system for Kuhn Axis mechanical and hydraulic disc drive spreaders, and for trailed Bredal spreaders from KRM and Güstrower machines from Ryetec Engineering.

Identifying the optimum switch-off and switch-on points for a fertiliser spreader is a challenging issue. For one thing, a spreader throws material almost as far behind the machine as it does to either side; for another, the distance is influenced by the type of material being applied.

It has been a major task for manufacturers to come up with calibration data for different materials and working widths that also takes into account forward speed. With variable spreading width, there is the added requirement to adjust the flow of material in line with changes.

For the operator, though, these systems simply make life simpler. Spreading is carried out around the perimeter of the field as usual with the border setting engaged at the discs, the spreader’s electronic control system in ‘manual’, and with the GPS system recording the pass.

This creates a headland reference point for on-off control, so for subsequent runs the operator no longer has to judge by eye when to push a button or flick a switch. The tendency is always to err on the side of caution and over-apply rather than risk missed patches.

And with the all-singing, all-dancing systems, spreading width is adjusted in steps wherever a significant overlap will waste fertiliser and add to the lodging risk.

There are two further plus-points: spreading can continue in the dark if necessary to catch up with a delayed workload; and the job could be entrusted to an inexperienced or less skilled operator if necessary.

 Amazone spreader

System: GPS-Switch

Spreaders: ZA-M Hydro, 3000-litre, 36m; ZA-M Ultra Hydro, 3600-4200-litre, 52m; ZG-B Ultra Hydro, 5500- and 8200-litre, 52m (trailed)

Disc drive: Hydraulic

Width adjust: Disc speed

Headland on/off: Yes

Variable width: 6 sections

 Amazone spreader

Amazone’s GPS-Switch system can be used with hydraulic disc drive versions of the ZA-M mounted and ZG-B trailed spreaders to automate an existing facility for manually adjusting the working width in steps on the move; it adds automatic headland shut-off and start-up. Spreading width is altered in three steps either side of centre by changing disc speed, so a machine spreading to 36m will close down in 6m steps. The system has its own operating terminal linked to the Amatron+ controller.

 KRM spreader

System: Auto-Switch

Spreaders: LW2 Trend – 700-2050-litre, 24m; M2W Trend – 1600-3300-litre, 42m; MW3 Trend – 3300-4500-litre, 42m

Disc drive: pto

Width adjust: Application pattern

Headland on/off: Yes

Variable width: 8 sections

The Auto-Switch system provides headland on/off and variable width control using a Patchwork BlackBox or TeeJet GPS unit with auto-guidance to provide instructions to the Bogballe Calibrator Zurf, Icon or Uniq spreader controllers updated with the relevant software. The fertiliser distribution pattern provided by the double-double layer, inward rotating spreading disc system is regulated to minimise over-dosing on short work and angled headlands. Auto-Switch can also be operated by an isobus terminal with section control.

 Kuhn Axis

System: Vari Spread

Spreaders: Axis 40.1 H EMC – 1200-3000-litre, 42m; Axis 50.1 H EMC – 4000-litre, 50m

Disc drive: Hydraulic

Width adjust: Feed-on point

Headland on/off: Yes

Variable width: 8 sections

 Kuhn Axis

In addition to headland on-off, Vari Spread adds auto spreading width adjustment for Axis spreaders with hydraulic disc drive and Electronic Mass Control (EMC) rate regulation. It can shut down the spreading width in four steps to left or right, or both sides simultaneously. It operates through the Kuhn CCI and other isobus terminals. Mechanical disc drive Axis spreaders can operate the system for left or right shut-off only.

 Vicon spreader

Spreaders: RotaFlow RO-M EW ISO – 1100-2000-litre, 24m; RotaFlow RO-XL EDW ISO – 1500-3450-litre, 45m.

System: GEOspread

Headland on/off: Yes

Variable width: 24 sections

GEOspread control software is available on the Kverneland IsoMatch Tellus isobus terminal to operate Vicon weigh cell spreaders with pto-driven discs. Spreading width is changed by altering the disc feed-on point using an electric actuator. With 24 steps of up to 2m each, a spreader working to 36m can shut down 1.5m at a time.

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