Reducing agricultural emissions

Improved controls on the storage and application of slurry and digestate.

Changes to the way that slurry and digestate is stored and spread on farms could lead to a reduction of up to 70% of the harmful ammonia that is released.

Amendments have been made to the Water Environment (Controlled Activities) (Scotland) Regulations 2011. These include improving controls on the storage of slurry and digestate to reduce leakage, and more targeted spreading to maximise the nutrient benefit and reduce emissions.

Agriculture is the largest contributor to ammonia emissions and a key element of the regulations is the phasing out of broadcast spreading of slurries by splash plates and the introduction of low-emission, precision spreading equipment.

The changes are being made following a 12 week public consultation and engagement with the agricultural sector and the National Farmers Union Scotland (NFUS). The changes will be phased in, with some farms having up to five years to comply.

Minister for Environment and Land Reform Màiri McAllan said:

“While slurry and digestate are important nutrients for use on our farms, they can also be damaging to our natural environment if not used properly, causing harmful emissions into our air and water.

“Agriculture accounts for around 90% of ammonia emissions. By using low emission, precision equipment, we can reduce the ammonia emissions by up to 70%, protecting our vital water environment and reducing the agricultural impact on climate change.

“This will also make an important contribution to the commitments on reducing air pollutant emissions from agricultural activity, which are set out in our new air quality strategy published earlier this year.

“We understand that farms will not be able to introduce these changes overnight. We have engaged with and listened to the concerns of farmers and where possible have made alterations that would allow us to meet the aims of the regulations while reducing the impact on businesses. 

“We will continue to work with the NFUS and our farming communities to ensure a continued thriving agricultural sector, while meeting our obligations to achieve net zero.”


The Water Environment (Controlled Activities)(Scotland) Amendment Regulations 2021 will come into force from 1 January 2022.

 Key facts:

  • The total quantity of slurry produced in Scotland is estimated at 6.35 million tons (1.67 billion gallons) per annum.
  • A single 10 m3 tanker of slurry can have an equivalent fertiliser value of between £30 to £50. Better use of the nutrients in slurry/manure/digestate can reduce fertiliser bills.
  • Spreading slurry using a splash plate can lose around 30% of the available nitrogen as ammonia gas in just the first 3 hours.


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