Archive Article: 1997/11/08

8 November 1997

Time is of the essence when spraying. A Cambridgeshire business has chosen a new generation sprayer to boost its spray capacity.

TO say spraying the 570ha (1,400 acres) cropped by a Cambridgeshire farming company was complex would be an understatement.

Russell Burgess Ltd, based at Yaxley, near Peterborough, owns four main areas of land, each with its own rotation, all within a five mile radius of its base.

Each year additional acres are rented from local farmers – depending on what is available and if the condition and rotation fits the requirements.

This year wheat, barley and peas accounted for half the 570ha, with the rest taken up by 80ha (200 acres) sugar beet, 93ha (230 acres) potatoes, 80ha (198 acres) onions, 100ha (250 acres) carrots and 12ha (30 acres) of parsnips. As usual, the crops were spread in a patchwork across the various parcels of land.

A conventional hydraulic sprayer used in such a diversified business would spend as much time washing out, refilling and travelling as was spent actually spraying in the field.

This changed dramatically this year with the arrival of a direct injection sprayer from Knight Farm Machinery.

According to Jason Burgess, the new machine from the Lincolnshire manufacturer can spend 50% more time spraying than before, and up to 120ha (300 acres) can be covered in a day – an impossible figure with the previous machine.

Not that the company was using a low-tech spraying system before – quite the contrary.

Nine years ago, recognising the potential of air-assisted spraying for reducing water volumes, one of the first twin-fluid nozzle sprayers in the UK joined the machinery fleet.

That was replaced by an air-sleeve machine – also from Knight Farm Machinery. The machines were self-propelled models and in both cases were backed up by a trailed sprayer at the busiest times.

The main attraction of both air-assisted systems was the low water volumes used, enabling a bigger area to be sprayed with each tank of chemicals compared with a conventional system.

But travelling and washing out still took up a large proportion of total time.

"It was common for the sprayer to fill up in the morning, go round all the sites spraying one crop and then return to wash out, fill up again and follow exactly the same route in the afternoon to spray something else," explains Mr Burgess.

"Each round trip could be 30 miles, plus there was the time spent washing out and filling up again. It was obviously not very efficient, and at busy times it was particularly frustrating."

A system which allows a variety of chemicals to be carried together on the sprayer, enabling all the crops at one site to be treated in a single visit, seemed the way forward.

The main difference between the new sprayer and most others is that the main tank is only ever used for carrying clean water.

Chemicals are carried in a series of small containers – one of 10 litres, three 25 litres and one 100 litres – and are mixed with the water on the way to the nozzles.

Each container is linked to an individual peristaltic pump suitable for transferring very precise quantities of liquid. A sixth container – a hopper for dry flowable powders – is on order.

Knight Farm Machinery fitted the US-developed Mid-Tech system for direct injection. The combination of containers and pumps can be altered to suit an individual farms spraying requirement.

At Russell Burgess the 10 litres container is typically used for applying low dose herbicides such as Totril (ioxynil) or Fortrol (cyanazine) on onions and sugar beet, while propachlor (Ramrod) would go in the 100 litres container.

Whatever set-up is decided upon, operators can spray fungicides, herbicides and trace elements singly or in combination in almost any ratio in a single trip without washing out.

The only contaminated material results from rinsing the chemical drums. Chemicals in self-sealing, returnable beer keg-type containers, will put an end to even this small amount of rinsing, hopes Mr Burgess.

At the start of a typical day the sprayer operators are given a spraying chart stating what chemicals are to be applied to which crops.

The containers on the sprayer are filled accordingly, and spare containers are loaded on the 17,000 litres bowser which will accompany the sprayer all day.

The two men – both trained sprayer operators – set off and share the spraying between them before returning at the end of the day.

The main tank and the chemical containers are refilled or changed as necessary during the day. A pump mounted on the front of the sprayer has cut refilling time down to just three minutes, so spraying can be virtually continuous. Previous machines took "a good hour" to wash out and refill.

Mr Burgess believes the new sprayer spends 50 % more time spraying than the previous machine, allowing up to 120ha to be covered at the busiest times.

As a result, the trailed sprayer is no longer needed for back-up and there has been a worthwhile saving in labour.

At the end of a spraying session the chemical lines are flushed out in a single operation using water from the 2,700 litres main tank. Only a few litres are needed, and they are returned to one of the chemical containers for disposal.

Chemical is applied by the Knight AirJet twin-fluid-nozzle system, mostly at 100 litres/hectare. The chemical application rate is controlled by a Knight DeltaSpray 3.

This system senses changes in ground speed and adjusts water or liquid pressure accordingly. All the operator has to do is choose the application rate – a task which can be done on the move.

As a major supplier of fresh vegetables to Waitrose, Sainsburys and Iceland, safe chemical use is a high priority for Mr Burgess. The substantial reduction in rinsings for disposal and improved handling procedures for operators are both welcome.

The direct injection system could also become part of a satellite-based precision farming regime. Maps are being prepared to record specific pest problems, and the latest combine has a yield data collection facility.

Patch spraying on cereals is a feasible operation in the near future, but less likely on the other crops.

The sprayer vehicle is a 125hp hydrostatic Challenger with four-wheel drive and four-wheel steering. Although the land is flat, some of it is very soft black fen, requiring quite a bit of power to drive through.

On one or two occasions when the sprayer has got stuck, emptying the main tank has done the trick. No problem there – it only has clean water in it!

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