13 March 1998

Big area calls for big tank

Switching to a 160hp

forward control sprayer has

meant a larger capacity tank

and more output for one

Cambridgeshire spraying

contractor. Geoff Ashcroft

reports

A STEADILY increasing workload to apply suspension fertiliser for Omex has seen spraying contractor Richard Redhead take a long, hard look at his fleet of three self-propelled sprayers.

With over 20,200ha (50,000 acres) of spraying to carry out each season – 10,100ha (25,000 acres) of which is applying suspension fertilisers – a higher capacity machine was needed.

And the result of Mr Redheads deliberations is that a £90,000 forward control Unimog U1600 equipped with a 3000-litre/24m (78.7ft) sprayer has just joined the fleet. It replaces a smaller Unimog U1200 which was struggling with the increasing workload.

"Despite a 2300-litre/24m sprayer, the smaller U1200 no longer had the capacity to do the work," explains Richard Redhead. "By moving to a forward control unit – and with more horsepower – I could fit a larger capacity spray tank which is also mounted further forward on the chassis to improve weight distribution."

Choosing the Unimog was an easy decision for Mr Redhead – despite the price.

"Few machines afford such a high level of comfort when spraying on ploughed land at up to 18kph," he says. "And with many jobs being small field plots,I can spend a lot of time travelling between jobs, so a good road speed is equally important. Its easy to cover 100 miles in a day."

The basic chassis conversion was carried out by South Cave Tractors at a cost of £65,000, though the price didnt include wheels and tyres. Mr Redhead sourced a set of Michelin 620/75 x 26 complete with rims for a mere £5000 (a set of 48in row crops are also due), while the spraying element took care of the remaining £20,000.

"Weve managed to keep the machine narrow to help manoeuvrability, but achieve a large footprint from the Michelin radials to help keep ground pressure as low as possible."

On the spraying front, Mr Redhead enlisted the services of local firm Techneat Engineering to put together his spraying package.

"The tank is straightforward enough, but applying suspension fertiliser requires a big bore pump and lines, with flood nozzles spaced at 3m intervals along the boom," he says. "We can fill a 3000-litre load in 5min and with fertiliser application rates of 200-2000-litres/ha, we can empty a tankful of fertilser just as quickly."

But to use the machine to apply pesticides, Mr Redhead plans to plumb in a second spray line with conventional nozzles.

The boom required a different approach.

"I needed a 24m boom which folded forward, so resisting the forces of high speed spraying when locked in the open position."

The result is a machine capable of achieving outputs of between 60 and 80ha/day (150 and 200 acres) – an increase of almost 50% when compared with the previous setup.

And with as much front overhang as the local bus driver, Mr Redhead feels comfortable with his investment.

"Without four-wheel steer, the Unimog would be a little awkward on the headlands but its quite the opposite – I just have to remember not to steer too early because Im sitting almost 10ft ahead of the front wheels."

Forward control and forward folding booms. Richard Redhead with his modified Unimog U1600. Total annual workload for his company amounts to over 20,000ha (50,000 acres).

Flood nozzles at 3m intervals on the 24m boom can apply up to 2000 litres/ha when operating at 10mph – it calls for a big bowser.