Silage Effluent

Silage effluent is produced from any forage crop which is being made, or has been made, into silage. It is also defined as a mixture consisting wholly of or containing such effluent, rain or groundwater emanating from a silo, silage effluent collection system or drain. In some intensive agricultural areas, silage effluent may be one of the commonest forms of agricultural pollution.

Silage DOs Silage DON'Ts   See also: Silage

Although animal waste is a major concern when dealing with nutrient loss and water pollution, silage effluent may also result in pollution, and contamination of water bodies in particular. Significant amounts of material may leach from large silos causing potential groundwater contamination.

Silage leachate contains high amounts of nitrates. Harvesting forage to be turned into silage at the correct moisture content and proper storage will reduce the volume of leachate from the silo. Other management techniques to reduce the volume of leachate coming from silos includes lining or sealing the bottom of earthen silos or trenches. Horizontal trench silos should have compacted clay bottoms or should ideally be lined with cement.

The silage should be covered with plastic to prevent rain water from entering and running through the silage. Not only will this reduce the amount of leachate, it will improve the quality of the silage.

In some cases, it is possible to collect the leachate from the silo and apply it to the land as a source of crop nutrients. In Burkina Faso, it was discovered that livestock preferred the soil soaked with silage effluent to commercially available salt licks.

Because silo leachate can burn crops, care should be taken in the amount of leachate applied to the field. Silos and trenches should be located as far as practical from wells to reduce the possibility of effluent polluting groundwater and entering the wells. A vegetated area should be maintained between the trench and any downslope pond, stream, or other surface water source.

 

Ensure that effluent tanks, channels, silo floors, walls and wall floor joints are inspected regularly and any necessary repairs carried out well in advance of the start of silage making.

Wilt the crop that is to be ensiled in order to reduce silage effluent production to a minimum.

Keep all effluent collection channels and drains clear of blockages.

Dilute silage effluent with a minimum of one-to-one (1:1) water if spreading on grassland to avoid scorching.

Avoid rainwater entering effluent collection systems.

Remember that silage effluent can be a valuable feedstuff or fertilizer. Think of it as a potential resource.

Don't build a silo or any part of the effluent collection system within 10 metres of a watercourse, or any other surface water, or drainage systems.

Don't store silage within 10 metres of a water source.

Don't allow silage effluent to enter a water body or groundwater.

Don't allow effluent tanks to overflow, or divert run-off from a silo into a water body. Similarly, don't use a soakaway to dispose of silage effluent.

Don't underestimate the quantity of effluent produced from wet silage.