OF ALL the techniques available for putting cattle slurry on to grassland, the simple dribble bar has become the firm favourite amongst farmers in south-west Scotland, according to contractor, Lee Dacre.

He still does some low-level splash plate application on hill land interspersed with gorse, but for the majority of field applications it is considered too uneven and volatile, resulting in loss of nitrogen to the atmosphere.

Trailing shoe application, which parts the sward to place slurry directly on to the soil surface, is subject to wearing parts costs that dribble bars do not incur, while at the top end of the application technology scale, disc injection into swards has benefits in terms of minimal odour and nitrogen loss to the atmosphere, as well as being able to return cattle to grazing sooner.

“But output is limited compared with other methods and the equipment costs more to buy and run, which has to be reflected in our charges to customers,” said Mr Dacre. “We used to do a lot of work with our 5m disc injector but now 95% of our work uses the two 9m dribble bars as they provide the best balance of cost, practicality and effective application.”

He has been handling farm slurry pretty much since he started contracting 12 years ago, operating on dairy and beef farms south-west of Dumfries. He runs two umbilical outfits, each comprising a tractor-mounted dribble bar, a reeler for the hose and an engine-powered pumping set.

Remote pump control enables Mr Dacre and his full-time operator, Dennis McKinder, to handle the whole process single-handed on most jobs, which is significant in making it a cost-effective service for farmers who need to relieve storage capacity while making good use of slurry as a nutrient resource.

“There are times when you need a second pair of hands, such as when pumping from an above-ground store, because someone needs to watch the flow into the sump,” he pointed out. “But when pumping from a lagoon we can operate remotely, switching between re-circulating to the lagoon while laying out the pipe and pumping to apply the slurry.”

And if a pressure-drop hints at a leak in the pipeline, the system can be shut-down immediately.

The pump set supplied by recently appointed Bauer dealer, Gordons, at Castle Douglas, is powered by a 175hp Iveco engine and features a Bauer Magnum SX2000 centrifugal pump.

“Every piece of equipment plays a key role, of course, but the pump has a big influence on our efficiency and running costs,” pointed out Mr Dacre. “We’re typically pumping slurry on level going at close to 200cu m/hr but more like 120-140cu m/hr uphill when it can be a hard slog for the engine.

“But this is a fuel-efficient outfit – by my calculations, it’s using 100-130 gallons (500-600 litres) of diesel to pump per million gallons of slurry, which I think is very acceptable.”

Servicing downtime, routine maintenance and rebuilds are other significant cost factors for slurry spreading contractors that are minimised by using a top-quality pump.

“The Bauer Magnum is not a cheap pump to buy because of the specification and high quality materials used,” Mr Dacre acknowledged. ”But running costs have been absolutely zero over the past four years and 3700 hours of work, even though it’s handled around 70m gallons of slurry in that time.”

Apart from changing the gearbox oil and adjusting the cutter plate twice a year to compensate for impeller wear, the unit has not been touched.

With dairy herds of 120 to 700, or even 800 cows typically housed year-round in the area, the constant production of slurry means this valuable resource is applied to fields three or four times a year to give grass a nutrient boost early in the year and after each cut of silage.

“I’ve also put slurry on to wholecrop barley a few weeks after sowing as a replacement for bagged fertiliser,” Mr Dacre reported. “With each application taking three to four days or more per customer, we’re busy most of the year apart from November and December when things are a bit quieter because of ground conditions.”

The work is charged at an hourly rate for all aspects of the service and the tractors have satellite-guided steering for accurate bout matching. Flow meters ensure slurry goes on at the rate needed to ensure every field cut for silage gets a dose.

His engine-powered pump sets can handle distances up to 2.4km, using 5-inch pipe to transport slurry to the 4-inch drag hose connected to the dribble bar.

For greater distances or a lift to higher ground, up to 600m of additional pipe is available together with a tractor-mounted Bauer Magnum SX1000 pto-driven booster pump.

“It’s a specialist job demanding good equipment, good organisation and the experience to lay pipe out in the field in a way that allows you to do the job efficiently,” added Mr Dacre. “Our objective is always to do the best job possible for farmers who want to make the most of their slurry.”