The days of spreading fertiliser at a blanket rate and paying little heed to plant requirement, accurate placement or, for that matter, to its effect on the environment must now be numbered.
And while this is largely down to the development of ever more advanced spreader designs, such technology still requires acceptance and implementation by growers if it is to be properly utilised and the gains and benefits realised.
For Robin Gaymer and his father Michael, who run a farming and a contracting business at Mentmore Park Farm, Mentmore, Leighton Buzzard, Bedfordshire, accurate application of fertiliser is considered to be essential.
“It just doesn’t make sense to apply fertiliser to where it is not required or in doses which are below or above the amount a plant can profitably utilise,” he says.
At Mentmore, Mr Gaymer grows about 2,000 acres of combinable crops – winter wheat, oilseed rape and spring beans in roughly equal amounts although he points out this year’s wet summer and autumn could result in an expansion in the spring sown area.
Contract farming agreements account for another 2,500 acres of cereals and more general contracting operations – which major on services for crop production rather than anything to do with livestock – bring the total acreage drilled to about 4,500 acres.
When it comes to fertiliser application, an increasing acreage has its nitrogen requirement applied as a liquid through the farm’s self-propelled 32m sprayer but P and K application remains the domain of a granular spreader which was purchased in February of this year – quite a few months ahead of its official launch date.
“We were one of the first UK farms to use Kuhn’s new Axis spreaders, which are probably the most advanced spreaders on the market,” he says.
The model used is the Axis 50.1 H EMC W, a tractor mounted machine with a working width of between 18m and 50m – Mr Gaymer works on 32m tramlines – and a useful 4,000 litre capacity hopper size.
“The first detail a spreader’s control system needs to know is where and how much fertiliser is to be placed and for this we have the farm and our contracted areas regularly tested to provide us with a soil nutrition map,” explains Mr Gaymer. “This information is down-loaded into the spreader control computer and, with GPS positioning, automatically increases or decreases application rates as a result.”
The really clever part though, is the Electronic Mass Control (EMC), which measures the flow of fertiliser onto each of the spreading discs by monitoring the pressure in each of the hydraulic drive motors and correlating the pressure with the actual mass flow. Any change in the target application rate is automatically adjusted by opening or closing the hopper apertures.
“The other advantage of EMC is that we don’t have to mess about with bags and weighing scales to calibrate the spreader – it’s all set in the cab,” he says.
One of the most regular mistakes made by fertiliser spreader operators is shutting off or restarting at the wrong time when turning on the headlands but this too has also been automated on the Axis – it’s called Opti-Point.
Mr Gaymer explains: “The first pass around the field sets the headland mark for the GPS guidance system so that when the spreader approaches it the fertiliser is automatically shut off and is re-started when the next bout begins. It is a system which forces the operator to sit on his hands and trust the system to do it for him – despite there being an almost irresistible urge to take over.”
When meeting the headland at an angle the Axis spreader also has a Vari-Spread function which not only progressively reduces the spread width of an individual disc but also reduces the amount of fertiliser so the application rate remains correct.
“This is an uncanny feature which you have to see to believe,” he says. “It works left or right and even together if it needs to. Combined with Opti-Point it allows the spreader to keep working to finish a field even if it is dark.”
Mr Gaymer runs his spreader on a JD7530 fitted with 900mm wide tyres which provide good support for the fully loaded spreader. The wheels are changed for narrower tyres as the year progresses.
Topping up the ‘like’ list are the weigh cells. These are an additional facility to EMC and, whilst not used in the metering system, they do tell the user how much fertiliser remains in the hopper at the end of a working period and how many bags can put in it without spillage. He also highlights the two side ladders – the second of which is an optional extra – which can be opened and used to stand on while cutting the base of the bags.
“These ladders ensure no one is standing between the loader tractor and the hopper,” he says, adding that his is a very dangerous place to be if the loader tractor should suddenly move.
In terms of control, the tractor is fitted with GreenStar and the spreader communicates directly to the tractor terminal through the ISOBUS system.
“It makes so much sense to use Isobus and avoid the clutter of all these different control systems in a cab,” he says. “I also save the cost of having to buy a Kuhn controller.”
Overall then, what is Mr Gaymer’s view of the new Axis spreader?
“I think we have moved into a new league,” he says. “The technology on this spreader ensures that providing we are doing our analysis correctly, the right amount of fertiliser is presented to the plants, wastage is virtually eliminated and the environment can only benefit.”
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