Bid to seek out the source of emissions
By Marianne Curtis
SLURRY is often perceived as a significant cause of pollution, but there is no room for complacency with its less potent sister – manure.
But pig research at ADAS Terrington, Kings Lynn, Norfolk, shows that manure emits higher levels of the greenhous gas nitrous oxide than slurry.
Nitrogen gases, such as ammonia and nitrous oxide, emitted from muck and slurry are regarded as serious atmospheric pollutants, says ADAS researcher Roger Kay.
With Integrated Pollution Prevention Control (IPPC) legislation imminent, MAFF-funded work at ADAS Terrington is seeking to understand where emissions of these gases are highest on-farm. Emissions from buildings, stored muck and slurry and spread muck and slurry are being examined.
Recent work has focussed on stored muck and slurry in winter and summer because temperature variation may affect emission levels.
"Emissions from stored slurry and muck were measured for a four-month period in winter and are still being measured over a four-month summer period," says Mr Kay.
"Manure gave off about 1.5kg of nitrogen. Much of it was harmless nitrogen gas, but one-fifth was the greenhouse gas nitrous oxide. This compared with slurry which emitted virtually nothing.
"So far, summer manure emissions are about two-and-a-half times winter emissions, whereas they are still virtually nil for the slurry."
• Gas emissions.
• Greenhouse gases.
• Winter versus summer.
Stored slurry gives off vitually no greenhouse gases in winter or summer, according to ADAS researcher Roger Kay.