a specialist
19 April 2002
Slurry injection pays for
a specialist
Contract slurry injection
could be coming into its
own as new regulations
place greater restrictions
on spreading and producers
appreciate the cost-saving
potential of slurry
nutrients. Mervyn Bailey
reports on one contractors
approach to the job
STARTING out with a round baling and ploughing operation, contractor David Underwood now specialises in slurry injection and muck handling, travelling up to 60 miles from his base at Upper Teen near Stoke-on-Trent, Staffordshire.
"Other contractors were prepared to do jobs at such low rates that I decided not to compete and instead look for more specialist work," explains Mr Underwood. "We tried a slurry tanker with a splash plate but this was not productive enough. Within a week, we did a trial-run of our our first injector and the customer liked the job so much he said that is how he wanted his slurry spread from there on."
Muckfast has now been in business for 10 years and although the majority of work is still carried out by an umbilical system comprising a pump, hose reel and Veenhuis shallow injector, a tanker-injector outfit has also been used for the past three years. The service is promoted through a web-site (www.muckfast.com) that explains the benefits of injecting slurry and the machinery available to do the job.
"When we first started out, nobody else was doing this type of work and there was not much competition," says Mr Underwood. "Other contractors have tried to muscle in but we have gained a vast amount of experience over the years and this gives us an advantage."
In the early 1990s, when injection machinery first started appearing in the UK, not many people had the experience of how to use the machines to their full potential. As a result, farmers often still have the misconception that injectors badly damage the turf. But this is no longer the case, now that designs have been refined and operators have a better understanding of the equipment.
"We have used 3m wide shallow injectors since we started as they penetrate the ground well but do not rip up the turf," he explains. "Bevelled discs push the soil apart and a trailing shoe places the slurry in the ground – we also have a more aggressive homemade injector for stubble work where ground disturbance is not a problem."
The advantages of injecting the slurry are clearly evident in the grass growth pattern, Mr Underwood points out. For example it is usually possible to tell where the injector has been lifted in and out of work. Surface run-off is avoided and cattle can return to graze fields sooner.
"More farmers now realise that slurry is an asset not a hindrance," says John Burnham of Veenhuis importer, Tanlake Farm and Machinery. "Dutch farmers have managed to reduce their purchased fertiliser inputs by controlling slurry rates rather than just pouring it on the field."
Nitrogen Vulnerable Zone (NVZ) legislation will also have an impact, he adds, as producers will have to reassess their application methods. Injection will be at the forefront, he believes.
Application accuracy is underpinned by the use of flow meters on Mr Underwoods injectors. These constantly inform the operator as to how much slurry is being applied and the area covered, so that the required application rate can be achieved by adjusting ground speed.
Also, using flow meters allows charges to be based on the volume of waste applied rather than the area covered.
"We charge per thousand gallons so it is important to have an accurate record," he explains. "Also, there is the environmental benefit of ensuring we do not over-apply."
Slurry is handled by a Doda L35 pump, which can push it up to 1600m along the pipe supplying the injector, at an average rate of 1864 litres/min (410 gal/min), depending on the distance involved and the consistency of the material. Application rate is typically 56,000 litres/ha (5000 gal/acre).
The umbilical system is fine for fields close to the farmyard. For fields further away from the lagoon, Mr Underwood purchased one of the first of the more modern Veenhuis tankers. Fitted with a self-filling system for rapid turnarounds, this 9500 litre (2000 gal) model carries a 3.8m (12ft 6in) wide mounted injector.
The tanker has a wider injector simply because weight can be transferred through the hydraulic lift rams to ensure penetration in summer when the ground is harder.
The same can be done with the tractor-mounted injector used for the umbilical system to some extent, but at some point the tractor tyres will lose traction and cause turf damage that Mr Underwood is keen to avoid.
"Weight is also an issue when spreading slurry as lagoons need to be emptied when fields are wet, and this is why we fit big tyres to our machines." *