General precautions to take when cutting silage

THE most common pathway for silage effluent to reach a watercourse is a storm water drain or land drainage system.

The risk of serious pollution, in such instances, is increased as the raw effluent can be rapidly delivered in a relatively undiluted state to a watercourse. The drain out- fall can be remote from the farmyard and the discharge may go unnoticed.

It is important to be familiar with all pipes and out-fall drains from the farmyard and regularly check for any signs of pollution. Look particularly for sewage fungus (grey slimy growth) at or downstream of out-falls. If you are in any doubt consider having a sample analysed.

Forward Planning

Silage pits, effluent tanks and collection channels should be checked for leaks well in advance of silage making and any necessary repairs carried out. Where a slurry tank is used to store silage effluent, spread enough slurry well in advance to ensure sufficient capacity is available. Allow 7,000 litres per 100 tonne of silage when spreading equipment is available on the farm, otherwise the available capacity should be 21,000 litres per 100 tonnes.

Effluent Management

Postpone silage making under very wet conditions. Check that effluent collection channels, gullies and diversion systems are working and set to deliver the effluent directly to the storage tank. To trap all effluent make sure the silage remains behind the front channel (and side channels in the case of slabs). Explain this requirement to the silage contractor. Serious pollution incidences have resulted from effluent flowing over pit walls. Do not over-fill walled pits. Divert clean water run-off from the silage pit cover by extending the polythene sheet over the effluent channel(s) when sealing the pit.

Storage Precautions

Broken weather can greatly effect the volume of effluent to be dealt with. Make sure run-off from flash flooding cannot enter the storage tank. Monitor the effluent level in the storage tank regularly and inspect watercourses down stream of the farmyard daily, once silage making begins. Remember effluent can continue to flow at significant levels for 6 to 8 weeks after ensiling. In the event of a discharge prevent it from reaching fish bearing waters or a public water supply source – block drains if necessary to form emergency storage. It may not be possible to deal with the root cause of the problem until the silage pit is empty.