silage
effluent
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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.
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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.
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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.
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