How to calibrate your fertiliser spreader
Published 27/01/2016 | 02:30
When was the last time you calibrated your fertiliser spreader? If you ignore this crucial job you are throwing money away with wasteful application of an expensive commodity.
The more prudent buyers amongst you will have specified a calibration and tray kit when you purchased the spreader.
If you don't have a calibration kit you can get your local dealer to calibrate the spreader for you.
This shouldn't cost any more than €250. It's a good idea to have the spread pattern checked at least once every two seasons using a tray test.
A tray test is simple. After laying the trays out across the machine's spreading width, a run through the trays is made with the tractor and spreader, as it would be operated in the field. Fertiliser collected in the trays is then transferred into corresponding test tubes and the contents are recorded.
From this data something called the Coefficient of Variation (CV) is calculated by measuring the variation in each tray from the average. The lower the CV, the better.
A CV of 10-15pc is acceptable and will prevent crop striping.