Sprayer built for suspension fert takes the field

26 February 1999

Sprayer built for suspension fert takes the field

By Andy Collings

A SELF-PROPELLED sprayer built specifically to handle suspension fertilisers is now operating in the eastern counties.

Owned by Anglian Farming Contracts (AFC), based near Diss, Norfolk, the machine is used to apply suspension fertilisers produced by J&H Bunn of Great Yarmouth.

The arrangement is that Bunn sells its fertiliser to customers as a deliver-and-spread package, with contractors providing the application element. AFC claims to have the lions share of Bunns East Anglian business and would look to cover 1500ha (3750 acres) each year.

Based on a short-wheelbase 160hp Unimog 1600, the 3500-litre, 24m spraying unit was designed and built by Knight Farm Machinery.

"Bearing in mind that application rates of suspension fertilisers can be as high as 2000 litres/ha, it was important we had a high volume machine," says AFC boss, Mathew Bradbury. "But we considered stability important and asked Knight to produce a tank which was as low and as wide as possible."

Knight appears to have achieved this requirement. Sitting fairly and squarely on the Unimogs platform, its height is about level with the top of the cab. Combined with the relatively short length of the whole unit and the fact that it is shod on oversize low ground pressure tyres, the overall appearance is of a chunky, go anywhere machine.

AFCs contract manager and sprayer operator, Gavin Norman, is more than pleased with the new outfit. "Our other sprayer is based on a JCB Fastrac, but with its smaller volume we tend to spend more time filling it than spraying," he says. "This Unimog combination should enable us to increase output significantly.

"Our turn round time is down to about three minutes and, with a 1000 litres/ha application rate, I can achieve about 40ha a day."

Mr Norman adds that time spent travelling between jobs has been reduced, although he concedes that larger diameter tyres may have some part to play in this.

Part and parcel of the sprayers operating system is a Dickey-John control unit, which allows ground speed volume control and, among a host of other running data, a facility to provide a detailed print-out of a specific job. That would include date, weather, time, formulation and application rate.

With the sprayer unit designed as demount unit, the end of the fertilising season will see the Unimog being used in AFCs other contract enterprises which include forage harvesting and baling operations.

The Unimog and sprayer represents a £75,000 investment for AFC, with Mr Bradbury aiming for a 10-year working life. He is clearly optimistic for a satisfactory return on his investment.

"Ignoring the value of the work performed by the Unimog during the "non-fert" season, our agreement with J&H Bunn is that, depending on application volume, we receive between £9 and £15/ha," he says.

"On a season which stretches from August to December in the autumn and from February to April in the spring, we should be on the right side of the job. All we need now is for it to stop raining." &#42


Bunns Suspension fertilisers are produced at the companys Seething Airfield site near Bungay. Mixed in 20t batches, customers can specify formulations to meet their requirements, including the addition of trace elements. Although a suspension, Bunn claims its mixing system allows formulations to remain intact, without undue settlement, for up to three weeks. Batches are made on a daily basis. The cost of suspension fertilisers falls between granular and liquid fertiliser prices with the added advantage that approved pesticides can be applied at the same time if required, according to the company. Bunns concedes the main market for its products is for the higher value crops such as vegetables or sugar beet.

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