John Deere is the first manufacturer to offer yield monitoring on forage harvesters, with the introduction of the AMS GreenStar system on its new 7000 Series machines fitted with an infinitely variable length of cut (IVLOC) transmission.
The system can be seen in public for the first time on the John Deere stand at Grassland UK, at the Bath & West Showground on May 7, 2003. Visitors will have the chance to test the system by guessing the weight of harvested grass in a trailer after one pass by the forager, in a competition that will run throughout the day at the John Deere demonstration area.
The company's GreenStar display, mobile processor and printer can be fitted to the forager to provide on the move yield monitoring, similar to the existing combine system. Full yield mapping and field boundary logging, using the StarFire satellite DGPS system, is being developed for future applications.
John Deere's unique IVLOC transmission allows the operator to adapt to different crop conditions within the same field and keep the machine running at optimum levels for peak performance. In combination with yield monitoring, this provides contractors with the ability to tailor their service to individual customer preferences, and to vary and monitor output not just from farm to farm, but from field to field or even trailer to trailer.
"For the first time contractors are now able to charge out foraging on a cost per tonne basis," says David Hart, John Deere's harvesting product manager. "We believe this is a fairer system than the common practice of charging by area, which often is not completely accurate, and takes no account of the load going through the forager.
"The ability to know the exact tonnage being harvested at any given time or place brings a number of genuine benefits to contractors, and helps keep the machine operating at peak performance.
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"Spot checks during harvesting will show the operator immediately if output is suffering from blunt knives, for example. Taking a short maintenance break to sharpen the knives could then yield big dividends in overall capacity."
In addition, says John Deere, contractor charges can be varied relative to yield; additives can be applied more accurately; optional print-outs provide exact records of yield per field and total harvested fresh weight, allowing more precise ration calculations; and routine maintenance and service can be matched to throughput, rather than simply to engine hours.
John Deere's GreenStar yield monitor system measures the amount of crop material passing through the feed rolls at any given time and calculates the weight from the volume. It does not currently measure the moisture content, so the yield relates to fresh grass, not tonnes of dry matter. The system is accurate to within 5 per cent, provided it is calibrated correctly, says the company.
This can be done by recording one load on a weighbridge, and keying the weight of the load into the yield monitor; the system relates this known weight to the volume and automatically calculates the calibration factor required, which can be adjusted to match different crops. The operator must also key in the correct swath width in the field and make adjustments if this changes during harvesting.
All information is shown on the GreenStar display, mounted on the right hand front corner post of the forager cab. The operator can view the name of the crop being harvested, selected from a pre-loaded list, and the field number; current crop yield and throughput (on the headland the average for the field is displayed); area harvested per hour; amount of crop harvested per trailer load; and summary information for each field and each crop harvested. There is also the option to show moisture content if this is known.
