As silage making begins in earnest, the Scottish Environment Protection Agency (SEPA) is asking farmers to follow a series of simple steps that will reduce the risks of pollution.

Silage effluent is the most common cause of agricultural pollution in Scotland: a clamp containing 500 tonnes of unwilted silage has the same polluting potential as the raw daily sewage produced from a city the size of Dundee. Even small amounts entering a watercourse can severely impact a watercourse: silage effluent rapidly strips oxygen from the water, killing fish, plants and other aquatic life. The polluted water will also be rendered unfit for drinking water supplies and for watering livestock.

Allan Virtue, Chairman of the Scottish Agricultural Pollution Group (SAPG) and a SEPA Team Leader, said:

"Despite the wet weather conditions last year, there was a reduction in the amount of pollution associated with making silage. This is very encouraging, and shows the value in adopting due care in managing the collection and storage of silage effluent. Farmers should be aware that pollution doesn’t have to occur before SEPA will take action.

"The Control of Pollution (Silage, Slurry and Agricultural Fuel Oil) (Scotland) Regulations 1991, which set minimum standards for installations used for the storage of such substances and their effluents, give SEPA the power to serve a notice requiring upgrading. Failure to comply with these Regulations is an offence."

The following simple steps will greatly reduce the risks of silage effluent pollution:

• Ensure that effluent tanks, channels, silo floors and walls are inspected and necessary repairs carried out well in advance of the start of silage making.
• Site silos as far away from watercourses as possible - under the Regulations, this must be at least 10 metres.
• Try, if possible, to wilt the crop to reduce effluent production.
• Keep all channels clear of blockages.
• Check effluent tanks regularly throughout the year, and empty as necessary.
• Avoid rain water entering effluent channels and tanks.
• Dispose of silage effluent by diluting with water and spreading onto land - ask SEPA for advice on how this should be done.

Silage effluent is extremely unpredictable and may bypass and leak from collection facilities, even when recognised good practice is followed. Early detection of leakage can avoid serious pollution, and farmers are advised to check watercourses likely to be affected on a daily basis during the silage making season and to contact SEPA to get advice on immediate remedial action if pollution has been caused.

For further advice, farmers should contact their local office. If you are unsure of the number of your local office, please call SEPA Public Relationson 01786 457700 who will advise you.