silage effluent
Ref: W07f

Silage liquor approaching stream

Silage is produced by cutting and storing a crop when it is still green; it is used on farms for animal fodder (food) as an alternative to hay. It can be made from grass and other green crops such as kale or clover. It is kept in a silo (an airtight concrete tower) or in stacks or pits covered with plastic sheeting. It is packed tight and starts to ferment (break down). When it is fermenting it produces a liquid called ‘silage effluent’. This effluent can be a great water polluter if it escapes into the watercourse. To avoid pollution accidents silage has to be stored and handled properly.

There are some things that can be done on a farm to decrease the risk of silage effluent pollution. By using a different crop like maize, silage effluent could be eliminated. Maize does not produce any effluent as it is dry when cut. Therefore the creation of silage effluent would be avoided.

Silage cutting	Silage cut in a field

By checking the weather forecast, a time for cutting silage fodder could be chosen so that the crop is at its driest. In this way the amount of silage effluent that is produced is reduced (W11).

Silage crops are left to wilt before they are collected for the silo. This helps to dry out the fodder. If the crop is left to wilt for longer it is even drier and will produce less silage effluent later.

Other crops like dried sugar beet shreds or barley can absorb the silage effluent. If these are mixed in with the green crop they can help reduce the amount of silage effluent that might escape into a nearby watercourse.

Black plastic pile

Sometimes silage effluent can be reused (W11) as it is full of nutrients and therefore it is not seen as a waste product of farming. For example the silage effluent could be recycled (W11) and used as animal feed. It would have to be diluted and a storage place is needed. The silage effluent could also be applied to the land as fertiliser.

If silage effluent is not handled properly on a farm and escapes into streams and rivers it can have a huge effect on wildlife, working against the balance of the environment.

Black plastic silage wraps - also a waste product - being stored on a farm for future re-use, recycling.