17 January 1997


UK fertiliser quality tests are beginning to bite overseas, according to a Shropshire-based calibration specialist. Andrew Blake reports

IMPORTERS are increasingly asking what they have to do to ensure their products meet the standards of the SP ratings system, says John Crowe of Independent Machinery Advisory and Technical Services.

The SP scheme, introduced three years ago currently covers only nitrogen fertilisers, but gives growers an independently-assessed indication of a products spreadability. Fertilisers are rated on a scale of one to five, the higher the number the better.

"More farmers are also beginning to ask me what the SP symbol on the bag means," says Mr Crowe.

In theory they should see all the numbers appearing. But there is no obligation on manufacturers to use the ratings, so in practice it is only being used where products merit a five, he says.

The real benefit of having an SP5 material is that it virtually guarantees consistency, says Mr Crowe who has over 30 years experience of testing and calibrating spreaders on farms, as well as being involved in fertiliser quality and spreader development.

Products which vary in quality are much harder to spread accurately, he explains. They may even be impossible to apply correctly with wide-spread spinners.

Costly error

Inaccurate application can be costly. By the time uneven spreading shows in the crop, losses in wheat can be a conservative £7-11/ha (£2.80-4.50/acre), says Mr Crowe. Quality in milling wheat and in malting barley may also be compromised.

"Growers have got to weigh up what poor quality fertiliser is costing them. In the past three to four years I have found more people looking towards good quality products." Much less urea has been used, he believes. "Its certainly difficult to get prilled urea to go to 24m with a constant, even spread, particularly in windy conditions."

Good fortune in the arable sector may have been responsible for the move to better, generally more expensive fertiliser. Growers may be tempted to switch back as margins tighten. But those who have had hassles working with inferior materials are unlikely to do so, suggests Mr Crowe.

"I think what will happen is that fertiliser and grain prices will follow each other." That should help keep better quality products attractive, he reasons.

Above: Time spent carrying out a simple spread pattern check should be well rewarded – whatever the fertiliser quality. Right:From box to tube – Edwin Parsons, tractor driver at Hut and Lodge Farm, Broadchalke, Salisbury, helps John Crowe (right) assess spreader performance. The grids in the boxes help prevent granule bounce, and the tubes display the eveness of spread. Such tests help pinpoint application errors.

See more