Applying nitrogen with a fertiliser spreader that has not been correctly calibrated can be a costly exercise according to fertiliser spreader specialist Chris Lightfoot.
At BCG’s Trials Review Day in late February, Mr Lightfoot said growers are suffering unnecessary productivity and profitability losses simply by neglecting to accurately calibrate their machinery.
Mr Lightfoot, who is involved in the Accu-spread program which independently tests spreading equipment for accuracy and evenness said the vast majority of fertiliser spreaders were delivering an unacceptably high level of variation in spread patterns.
“And using a new machine is no guarantee that an acceptable spread pattern will be achieved,” he said.
According to Mr Lightfoot, with the machinery currently in use, growers should be aiming to achieve a uniform distribution over the paddock.
He said by calibrating a spreader it is possible to work out the width between runs that delivers the desired degree of evenness.
Research initiated by Fertiliser Australia that investigated the financial outcomes of spreader calibration (around $500 per machine) revealed that most spreaders deliver sub-optimal spread patterns, costing growers between $25-40/ha. As such, calibration was deemed cost effective.
“While each situation will be different, my analysis shows that sub-optimal fertiliser spreading will always reduce the return,” Mr Lightfoot said.
“The ideal outcome would be to have the application rate vary according to the localised soil nutrient levels and crop requirements but in practice, with the machinery currently in use, our best bet is to achieve a uniform distribution over the paddock.”
When calibrating the fertiliser spreader, Mr Lightfoot said the aim was to achieve a 15 per cent coefficient of variation (CoV).
“This is the magic number used to calculate the optimum bout width at which the spreader should be driven,” he said.
“In practice the 15 per cent CoV is an approximation but it provides a bout width that is very close to the absolute optimum and as such provides a robust result.”
In a bid to improve understanding about crop nutrition, BCG has been carrying out work on behalf of the GRDC’s More Profit from Crop Nutrition initiative.
As part of this initiative, crop nutrition workshops are being held across the region which may include a spreader calibration demonstration day (according to grower interest).
To find out more about how to achieve More Profit from Crop Nutrition phone BCG on 03 5492 2787.
