10 April 1999


Herbicides are the most expensive input on sugar beet. Gilly Johnson asks how growers might trim spray costs.

HOW much will you pay out for sugar beet herbicides this spring? Probably too much, according to data gathered by British Sugars grower survey. Careful planning could bring this bill down by perhaps £10-20/ha, say Mike May of IACR Brooms Barn and Robin Limb of British Sugar. Nationally, such savings could add up to £2m.

Average spend last year was £119/ha; this figure comes from the companys 100-grower sample on its new computerised benchmark system, which draws on a representative grower group taken from throughout the beet growing area. The figures are true commercial costings from businesses ranging in size, and the spread of herbicide costs is wide – from £211/ha down to just £29/ha.

The top 10%, calculated on the basis of enterprise margin, did spend less than the average – but not by that much at £110/ha. At the bottom of the scale, the figure for the worst 10% is £30/ha. Surprisingly, this is not related to yield performance – theres virtually no difference in weed control costs for high and low yielding crops.

A clue as to whats happening is found when the size of the beet contract is taken into account, where herbicide costs are clearly less for growers with smaller contracts (below 500t). Businesses with more beet – over 1300t – are spending £17/ha more. The average size of the beet contract is 850t.

Growers with large areas of beet are spending more because they dont have either the time or the flexibility to tailor inputs to individual situations, suggests Mr May. "But like all insurance policies, they should be looking to reduce the cost of the premium."

One solution might be the FAR system, where a simple mix of actives is applied at short, regular intervals. The risk of getting it wrong is minimal, but the business has to have sufficient spray capacity to cope with treating large areas frequently.

Weed control was less expensive in last seasons wet spring, says Mr May. But even so, growers are spending more on proprietary co-formulations, when they could be mixing their own from cheaper building block products, suggests Mr Limb.

The advantage of co-formulations is that they might give you extra flexibility on timing, allows Mr May. But the disadvantage is that you might be paying for the privilege.

"Beet herbicides consist of old, well understood actives; there are only a handful of building blocks although products are being constantly repackaged which makes weed control seem more complex than it really is," says Mr Limb. "This is another advantage of the FAR system; you know what you will be using, and can source the actives more cheaply and mix your own."

Another option is to use inter-row cultivation to keep weeds down. Its thought about half of beet growers use a tractor hoe as a substitute for at least one spray. But fully costed, including diesel, labour and depreciation, the price of a tractor hoe operation is about £28/ha. Mr May suggests using tractor hoeing as part of a planned integrated approach – instead of just running through the crop when the opportunity occurs. "You might be able to reduce spray doses in tandem, for example."

Consider tailoring dose to weather conditions – but be careful about possible crop damage, says Mr Limb. Early morning sprays are more effective, and treatments applied under warm temperatures and when light intensity is high offer opportunities for cutting rates.

The weeds to watch, which must be controlled early, are knotgrass and fat hen; one per square metre should set alarm bells ringing. That apart, dont be too house proud about a weedy crop, says Mr Limb.

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