Spreader systems accurate to within 3%
REQUIRED fertiliser rate is generally defined as weight of product/acre. It is ironic then, that the vast majority of spreaders meter fertiliser in respect of volume or, put more basically, the size of the hole at the bottom of the hopper.
Variable fertiliser quality, density and flow rate characteristics make the "hole at the bottom approach" at best a compromise and at worst, a severely under or overdosed field.
Lely has now introduced a system for its Centerliner Supabowl spreaders which employs an electronic weighing device capable of constantly registering the rate of fertiliser leaving the hopper. Linked to a computer programmed with required rate and fed with forward speed data, the machine is able to automatically maintain application rate in respect of changes in tractor speed. Lely claims a sustained accuracy of within 3% of the required rate.
Key to Centermatic ll, which is basically an advanced version of the companys existing Centronic ll system, is the weigh cell. Positioned at the top of the machines A-frame, its output is constantly averaged by the computer to take into account variations caused by rough ground conditions.
In operation, the required application rate and working width is entered into the computer followed by a three figure number. This latter input, listed in the operators handbook against application rate provides the starting setting for metering outlet.
Once spreading has commenced, the computer checks if the required weight of fertiliser is being applied in respect of area covered and automatically makes any adjustment that may be necessary. And then keeps on checking.
Price of the Centermatic ll system is not cheap – it adds another £4040 onto the price of a Lely spreader already equipped with the Centronic ll system.
The Centerliner Supabowl CB3000 model (30cwt) for example, complete with Centronic ll has a list price of £10,375. *
Lelys Centronic weighing system and, inset, the on board control box. Fertiliser rates can be increased or decreased in 5% steps while on the move.