4 December 1998

Patch sprayer on song

THE race for the worlds first commercial patch sprayer continues. Latest contender offering a system is Chavtrac, which now offers a multi-chemical option.

Sourced from US manufacturer Raven, it has at its business end a chemical injection system which, acting on commands from an onboard computer, automatically injects chemical into the water flow. Siting the injector actually on the boom minimises the time taken from injection to application – and means that, with the boom lowered to waist height, no awkward lifting of heavy concentrate containers is required.

Chavtrac is able to offer a combined system which can use up to four different chemicals at the same time.

Having the chemicals to hand is one thing, but knowing which chemicals should be applied, how much and where, is another matter.

The solution is to have an accurate weed map from which, using the office computer, chemical applications can be decided. Once programmed the computers information is down loaded onto a card and inserted in the tractors computer. This information, combined with a GPS navigation system enables the sprayer to know what to apply and where to apply it.

Chavtrac says it already has one version operating in UK conditions and is currently evaluating its performance.

Such technology however, is not cheap. A four chemical injection system carries a price tag of £12,500, a GPS control system another £5300 and software and data handling a further £2000. Add this lot – over £20,000 – to the £56,400 price of a self-propelled Chavtrac 405/3000 sprayer and prices reach the big league.

But Chavtrac maintains that efficient patch spraying could reduce chemical spend by up to 25% and, on larger farms this investment could see a useful return.