Farmers may need to re-think livestock nutrition and housing to meet new ammonia emissions targets, says expert
PUBLISHED: 08:33 07 December 2018 | UPDATED: 09:16 07 December 2018
The government’s urgent drive to reduce agricultural ammonia emissions will demand a sharper focus on livestock nutrition, building design and slurry storage, East Anglian farmers were told.
Industry experts outlined ways to prevent the gas being released into the atmosphere from sources such as manure and fertiliser, during a knowledge-sharing meeting at Diss Rugby Club.
The meeting heard that agriculture is responsible for 88pc of all UK emissions of ammonia, which can be damaging to the environment and combine with other pollutants to form particulates which are harmful to human health.
Those attending were predominantly pig producers, who were told that their sector accounts for 7pc of farming’s total emissions.
Nigel Penlington, head of buildings and environment at the Agriculture and Horticulture Development Board (AHDB) said the government’s draft Clean Air Strategy, published earlier this year, had ramped up the pressure on farmers to meet stricter limits on emissions.
He encouraged them to assess each stage of their production process – starting with feed efficiency.
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“The sooner you can make a process more efficient, then the less you have to deal with later,” he said. “If you have got a more efficient engine on your care which uses less fuel, hopefully it will produce less exhaust gases and take you further per gallon.
“With animals, feed goes in one end, and you can only retain a certain amount of it before it comes back out the other end and you get urine and faeces. “The more you can retain in the animal and convert into what you are trying to produce, whether it is piglets or meat, the less is going come out that you will have to deal with.
“The established view is that if you reduce feed protein levels by 1pc you take 10pc off your ammonia emissions. That was probably fine 20 years ago when the protein levels were higher than they are now, and the ammonia levels were not quite as high.
“Some nutritionists have been challenging this approach and saying they [protein levels] are as low as we can get now. Also there is a lack of independent evidence now linking modern genetics, crude protein and lean growth.
“Protein intake and balance are the main factors influencing nitrogen excretion while reducing ammonia. Speak to your nutritionists, because they know your system and there is going to be a growing role for nutritionists going forward.”
READ MORE: Farmers must prepare for government crackdown on ammonia pollution ‘before the carrot turns into a stick’
Mr Penlington outlined a raft of other practical measures which pig producers could take to optimise their buildings to limit ammonia emissions, including keeping slurry and urine apart to prevent chemical reactions, minimising emitting surface areas, frequently emptying slurry pits and covering slurry stores. They could also consider computer-controlled ventilation and floor insulation, a vacuum system for efficient slurry removal or air-cleaning biofilters – all of which could make significant reductions to emissions.
“But you don’t need to make a huge investment to make a really significant difference,” he added.
The meeting, which also discussed grant funding opportunities for ammonia reduction projects, was co-hosted by the Catchment Sensitive Farming partnership – comprising Defra, the Environment Agency and Natural England.
Paul Arnold from Natural England said while reducing nitrogen run-off from farm fields into watercourses had always been a priority, the renewed focus on ammonia emissions had been driven by Defra’s Clean Air Strategy, which sets out stricter controls on livestock housing standards and spreading fertiliser.
“Ammonia is a form of nitrogen and if it is up in the air it is a wasted resource,” he said. “We have spent a lot of time thinking about how we stop nitrogen getting into watercourses and keeping it in the field, but now we need to think about how we stop it going up into the atmosphere as well.”