Are sprayer issues hitting your pocket?
IT’S AMAZING how year after year farmers pay big money for fertiliser and yet don’t bother setting up their spreader properly.
Those who overlook calibrating their spreader face financial losses as costly fertiliser is either over-applied, under-applied (leading to yield drops) or spread in uneven patterns (leading to striping).
Some farmers may have specified a calibration and tray kit with their spreader when they were buying the machine.
If you didn’t, consider the option of asking the machinery agent who sold you the spreader to calibrate it for you.
This shouldn’t cost any more than €250 for entry level spreaders. It’s a good idea to have the spread pattern checked at least once every two seasons.
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.
Level ground and wind free conditions are essential. 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 seen as being acceptable and most industry experts agree will prevent crop striping. However, surveys indicate that a lot of spreaders in use today have CVs of 30pc or more leading to financial loss and inefficient application.
Research has shown that improving the CV from 30pc down to 10pc will bring a yield benefit of around 0.25t/ha in wheat, so it is a worthwhile job.
If your CV is well off target it could be an issue with worn vanes, incorrect spreader height or sometimes even top link setting. Consult your local machinery agent to fix the problem.
Correct spreader settings are machine specific and are based on the type of fertiliser being spread and the bout width chosen.