18 January 2002

In-crop spring slurrys a winter wheat bill saver

HOW do you fancy saving up to £82/ha (£33/acre) on your winter wheat fertiliser bill? It can be done, says ADAS.

A 50cu m/ha (4400 gal/acre) spring top-dressing of 4% dry matter pig slurry provides nitrogen, phosphate and potash with that sort of value, says ADASs John Williams.

"The problem is that few farmers have the confidence to reduce fertiliser inputs when slurry has been applied. Perceived difficulties with spreading it evenly and uncertainty about nitrogen availability are the usual reasons for their concern."

But new technology, such as band spreaders with trailing hoses and shoes, should encourage more growers to take up the idea, Mr Williams believes.

Further encouragement can be found in the recently updated DEFRA publications RB209 and Managing Livestock Manures booklet and in ADASs free MANNER computer software. These highlight the adjustments required in other fertiliser applications. "They are valuable tools helping farmers maximise the value of their slurry applications.

"Improved slurry use has allowed many farms to make considerable savings in production costs without compromising crop yield or quality."

ADAS and IGER are showing what can be achieved on four commercial mixed farms as part of DEFRAs Making the Most of Manure campaign.

The savings, increased flexibility and reduced odour nuisance help offset the capital outlay of £10,000 and 10-year depreciation costs for the band-spreading equipment, claims Mr Williams.

&#8226 Valuable nutrient source.

&#8226 Lower nitrogen losses.

&#8226 New application equipment.

&#8226 Demo farms proving system.

Band spread keeps it clean

AT Horsewold Farm, near Driffield, East Yorks, a 21m SAK trailing hose boom on a 13cu m (3000gal) Redrock tanker allows slurry to be top-dressed evenly to winter cereals and oilseed rape in spring.

"The boom fits the tramlines so the slurry can be treated like a liquid fertiliser, going on in bands to the soil surface so the crop stays clean," says John Williams.

Measurements show ammonia losses afterwards on the arable, pigs and duck unit are about 40% less than with conventional surface broadcasting.

Typically half the readily available nitrogen in autumn slurry dressings is lost by leaching. "Spring band spreading minimises ammonia and nitrate losses and allows the most to be made of the slurrys fertiliser value."

For the 1999 harvest at Horsewold, a trailing-hose spring dressing of pig slurry to winter wheat provided 80kg/ha of N worth £24/ha. Broadcast on stubble the previous autumn the same volume offered only 15kg/ha of N worth just £4/ha, he calculates.

Demonstration host William Bradley says the smell from the system is much less than with surface broadcasting. "Our applications are also unaffected by wind, so there are more days when we can spread."

Travelling with the heavy machinery in early spring can be difficult on his silty clay loam soils, but the wide boom allows dressings to be delayed until April when conditions are usually drier.

But with full use still possible only one year in four it could take many years to repay the equipment outlay, he says.

At Berrowsfield Farm, Inkberrow, Worcs, Tim Tyrrell applies all his separated cattle slurry to grassland with a trailing shoe attached to an umbilical system.

The shoe places slurry under the canopy to keep the sward clean so grazing can start within days. "It has certainly increased our window of application, but I see it mainly as a contractors tool."

In Cheshire, Paul Moore has one years experience of band spreading slurry over his 12m tramlined whole crop wheat at The Grange, Betley. "It is certainly very accurate, but we do have to use quite large tyres which might not suit wheat perfectionists." &#42