Environmental guidance for your business in Northern Ireland & Scotland

Silage Regulations

Silage Regulations

What you must do

Notify your environmental regulator in writing before you use new or substantially reconstructed or enlarged silage stores.

In Northern Ireland, the Northern Ireland Environment Agency (NIEA) requires at least 28 days' notice.

In Scotland, SEPA requires at least 28 days' notice.

Contact your environmental regulator

Silo design and construction

You must design and construct your silos either:

  • in accordance with standards on cylindrical forage towers: in Northern Ireland the correct British Standard (BS) is BS 5061, and in Scotland it is BS 5502, or
  • in accordance with the requirements below.

If you don't use BS 5061 or BS 5502, you must:

  • Extend the base of the silo beyond the walls and include a perimeter drainage channel to collect silage effluent in a tank. If the walls are made of earth, you do not have to extend the base beyond the walls.
  • Provide a silage effluent tank with a minimum capacity of 3m3 per 150m3 of silo capacity for silos up to 1,500m3. For larger silos, the tank capacity should exceed 30m3 plus 1m3 for each 150m3 of silo capacity over 1,500m3.
  • Use impermeable silo bases, tanks and drains.
  • Make the base and walls of the silo and the effluent tank resistant to attack from silage effluent. You can buy commercial treatments for this purpose.
  • Line the walls of earth bank stores with an impermeable membrane.
  • Site your silo at least 10m from any water, including field drains and ditches.
  • Use retaining walls that are capable of withstanding the loadings indicated in the British Standard (BS 5502: part 22: 1993). Display a notice that shows the maximum loading and make sure you do not exceed this amount.
  • Construct silos, above ground effluent tanks and drains that will last for at least 20 years with proper maintenance.
  • You must design and construct tanks that are below ground, or partially below ground in accordance with BS 5502 so that they last 20 years with proper maintenance.

British Standards website

Baled and field silage

Store any open baled silage that is wrapped or sealed in impermeable bags at least 10m away from any water, including field drains and ditches into which silage effluent could enter if it were to escape.

You must not make field heap silage.

Store silage made in bulk bags at least 10m from any water, including field drains and ditches into which silage effluent could enter if it were to escape. You must use bags that are made of 1,000 gauge polyethylene or equivalent and you must seal them to prevent effluent escaping. The bags must be stored on a firm, level surface with facilities to safely remove excess effluent.

Further information

The codes of good agricultural practice provide guidance on how to avoid polluting water with silage effluent.

In Northern Ireland, see section 2 of the DARD code of good agricultural practice for water, air and soil.

DAERA: Code of good agricultural practice for the prevention of pollution of water, air and soil

NIEA SSAFO Regulations in Northern Ireland

In Scotland, see section 7 of the Prevention of Environmental Pollution from Agricultural Activity (PEPFAA) Code.

Scottish Government: Prevention of Environmental Pollution from Agricultural Activity (PEPFAA Code) 2005 (Scotland) (Adobe PDF 1.34MB)

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