30 January 1999

PRECISION PARTNERS HIPS

Youve got the spreader and the GPS monitor – but will the two work together? Peter Hill pieces together the kit needed for variable-rate fertiliser application.

MAPPING of crop yield and soil types is usually the first application of precision farming technology. But variable-rate fertiliser application is the first operation regulating inputs to be used to any extent on commercial farms.

Growers mostly rely on outside contract services already running systems that work. Early attempts at farm systems were somewhat hit-and-miss but much development work has gone into computerised electronics which will communicate and understand each other. The result is a growing number of spreader/controller/GPS system combinations that can be used with confidence.

To apply fertiliser (mostly P & K at present) at rates tuned to the requirements of distinct field areas demands three items of equipment:

&#8226 a fertiliser spreader equipped with a power-adjusted application mechanism.

&#8226 an electronic brain programmed with essential calibration data.

&#8226 a monitor or data processor capable of reading digital rate maps and dGPS position data to tell the spreader what rate is required at any given time.

There are several ways in which this can be done. Most common is to use a tailor-made system from instrument specialists RDS Technology, LH Agro or Raven Industries (via Tech International).

But it is also possible to use data processors from these companies with controllers supplied on the spreader – such as the KRM Calibrator 2003, Kuhn Quantron L and Amazone Amatron or Amados. Or these controllers to monitor/ processors such as AGCOs Fieldstar and Claas ACT. The permutations are almost endless.

In future, spreaders are just as likely to be equipped with or coupled to a dedicated computer carrying calibration data but without control functions of its own. Instead, spreader functions will operate through GPS monitors. Amazone and KRM already have such devices, Kuhn will have soon.

The main attraction is one easier-to-use control system taking up less cab space. Whatever provides the spreader-to-monitor link, a two-way partnership is required so that actual application rates – as opposed to planned rates – are recorded in case the system goes awry or the operator decides to over-ride the automatic system.

Of the GPS monitor/controllers available, the AGCO Fieldstar system, available on Massey Ferguson and Fendt tractors, is the most widely used. Claas now has its ACT system commercially available, and Deeres Greenstar and Deutz-Fahr LBS are about to appear. Case will shortly have a monitor/controller as part of its AFS system.

From the electronics specialists come the RDS Hermes/Apollo/ Jupiter combination, the SOYL-Opti (from soil sampling/fertiliser application specialist SOYL, using LH Agro equipment with specially-written software), LH Agros own DataLink LH 5000 system, and the US-made Raven AMS from Tech International.

The latter has been adopted by Horstine Farmery to bring automated variable rate application to its range of pneumatic spreaders. The AMS is linked to an electronic controller that – like all the others fitted to spreaders capable of GPS-guided spreading – compensates for changes in forward speed to keep the application rate consistent.

With Horstine Farmerys Cascade boom-type fertiliser distributor, and Kuhns Aero boom spreader, that is achieved by altering the speed of the positive displacement feed rollers that meter fertiliser into the distribution tubes. The same is done when the GPS monitor reads that a change of rate is required in a particular part of the field.

On disc type spreaders, the same effect is achieved by altering the size of the hopper outlets so that more or less fertiliser is allowed to flow on to the discs. Spreaders equipped with weigh cells – the Vicon Rotaflow RS-EDW and KRM EXW Trend – have the additional refinement of an automatic and speedy calibration process allowing calibration settings to be easily updated for variability in weather conditions and fertiliser sample affecting flow rate of material from the hopper.

Spreaders with conveyor belt feed get round this problem by working to a set delivery volume – so flow characteristics have no bearing on the application rate. Mostly, these are large capacity, trailed spreaders, but two suppliers – KRM-Bredal and Transpread – also produce tractor-mounted spreaders with conveyor delivery.

Altering application rate with these machines involves changing the speed of the conveyor feed belt. Normally, this is done through land-wheel drive to maintain consistent application. But for GPS-guided spreading, this is substituted by hydraulic drive regulated by an electronic controller coupled to the GPS monitor.

Spreaders equipped for GPS-guided, variable-rate fertiliser application

Amazone M-tronic, MAX-tronic, ZA-M Maxima

Rate control: Ground-speed related using Amazone Amados or Amatron II and Amatron II ARS electronic control and monitoring system to alter size of hopper outlet, or spreader-mounted job computer for connection to AGCO Fieldstar or Claas ACT implement controllers/monitors.

dGPS data compatibility:

AGCO Fieldstar

Claas ACT

RDS Hermes + Jupiter

RDS Pro Series 8000

Soyl-Opti

Horstine Farmery Cascade

Rate control: Ground-speed related with adjustment of positive displacement metering feed roller speed by Horstine VRC electronic control system.

dGPS data compatibility:

Raven AMS

Soyl-Opti

KRM Bogballe DZ Trend, EX Trend, EXW Trend

Rate control: Ground-speed related by adjusting metering outlet size via Calibrator 2003 implement controller. Automatic and continuous re-calibration with load-cell equipped EXW.

dGPS data compatibility:

AGCO Fieldstar

Claas ACT

LH Agro

Raven AMS

RDS Hermes + Jupiter RDS Pro Series 8000 Soyl-Opti

KRM Bredal K and B-XL series

Rate control: Ground-speed related by electronically-adjusting speed of hydraulic drive feed conveyor using RDS Apollo, LH Agro 5000 or Raven SCS660 controllers.

dGPS data compatibility:

AGCO Fieldstar

Raven AMS

RDS Hermes + Jupiter

RDS Pro Series 8000

Soyl-Opti

Kuhn MDS 1141 and Axera-H

Rate control: Ground-speed related by regulating hopper outlet openings using Kuhn Quantron L (LH Agro) electronic controller/monitor or spreader-mounted job computer coupled to AGCO Fieldstar or Claas ACT monitor/controller.

dGPS data compatibility:

AGCO Fieldstar

Claas ACT

LH Agro DataLink

Soyl-Opti

Kuhn Aero

Rate control: Ground-speed related using Kuhn Quantron L (LH Agro) electronic controller/monitor to regulate speed of positive displacement metering rollers or spreader-mounted job computer coupled to AGCO Fieldstar or Claas ACT monitor/controller.

dGPS data compatibility:

AGCO Fieldstar

Claas ACT

LH Agro DataLink

Soyl-Opti

LELY Centreliner

Rate control: Ground-speed related using RDS Apollo 5 or Raven SCS660 controllers.

dGPS compatibility:

AGCO Fieldstar (Apollo 5)

Raven AMS (Raven SCS660)

RDS Hermes + Jupiter (Apollo 5)

RDS Pro Series 8000 (Apollo 5)

Soyl-Opti (Apollo 5 & Raven SCS660)

RECO Sulky GLX

Rate control: Ground-speed related by altering hopper outlet size using Sulky DPB electronic implement controller/monitor.

dGPS data compatibility:

AGCO Fieldstar

RDS Hermes + Jupiter

RDS Pro Series 8000

Soyl-Opti

Transpread 500V & 830 series

Rate control: Ground-speed related using Transpread ComputerSpread electronic control of hydraulic drive to feed conveyor.

dGPS data compatibility:

Raven AMS

RDS Hermes + Jupiter

RDS Pro Series 8000

Vicon Rotaflow RS-EDW

Rate control: Ground-speed related with automatic and continuous calibration using Vicon EDW electronic control, monitoring and hopper weigh cell system.

dGPS data compatibility:

AGCO Fieldstar

RDS Hermes + Jupiter

RDS Pro Series 8000

Soyl-Opti