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Effluent control - are you ready?

Donal Gormley, Countryside Management Adviser, Omagh

With the silage making season underway, it is very important to give special attention to the collection and storage of silage effluent.
With the poor weather that has occurred over the past few weeks, problems may be encountered with silage making, as dry matters may be low. Effluent production varies with the dry matter of grass at ensiling and with height and weight of silage in the pit.
At 25 percent dry matter there is very little effluent produced whereas at 16 percent dry matter, effluent production is approx 225 litres per ton.
It is very important, not only from a pollution point of view, but also from a nutrient recycling process to have adequate effluent collection facilities. When effluent enters a river or stream, it leads to a rapid increase in bacteria and other micro-organisms who use up the available oxygen, therefore giving a rapid reduction in the Biological Oxygen Demand (BOD) levels and damaging the aquatic life in the water.
How do you prepare for efficient effluent collection?
  • Check the silos for any cracks or holes, repair immediately.
  • Clean out all effluent channels thoroughly and check that the outlets from the channels are free of debris and are running efficiently.
  • It is also good advice to use drainage pipes at the walls to allow the effluent to drain away quickly. Using a shake of straw over the top of the pipes helps to improve the drainage even further.
  • Aim to maximise the dry matter of the silage crop by wilting the crop wherever possible to reduce effluent production.
  • The level of effluent collected in tanks should be checked regularly to ensure that overflow does not occur.
Peak effluent output occurs from day two to day six after ensiling and peak flow rates of up to 20 litres per tonne per day is possible. Make sure tanks are adequate and the collection system is working properly before harvesting starts.
For any further information on this please contact your local Countryside Management Branch.