Silage effluent management in the farmyard

Farmers need to ensure that silage storage facilities are fit for purpose before this year’s silage season. The silage pit and silage effluent collection and storage facilities must meet the standards required by the Department of Agriculture and Food (DAFM).

Silage pits – slabs and walls, need to be structurally sound to ensure ensiling is completed in a safe environment. Silage effluent collection channels and tank storage must be capable of storing the volume of effluent generated. The effluent is a highly polluting and can cause fish kills in watercourses/rivers and contaminate wells if not collected, stored and landspread properly.

While silage pits are empty, now is the time to examine the silage pit slabs, walls and channels to see what maintenance and repairs are needed before the silage pit is used again in 2023.

Maintenance checks

The first step is to wash down the silage pit using a power washer, especially the floor, effluent channels and collection tanks to enable problems to be fully assessed. Look out for cracks, porous patches, unsealed and eroded joints. The extent of the damage can be assessed by hacking away any unsound concrete at joints and at the base of walls. The silage pit, channels and collection tanks must be leak proof and all the silage effluent must be collected and safely stored. If the pit is not fit for purpose, cease using until all repairs are completed.

Repair works must be completed to Department of Agriculture and Food (DAFM) specifications for Concrete Silage Bases S128 and Resurfacing of Silo Floors S128A.

Regular maintenance of the silage pit ensures that minor problems are attended to while still minor.

Silage storage

Many of the problems with silage effluent arise from farmers attempting to ensile more silage than the slab is designed to hold. Additional silage should be stored on another slab or made into round bales.

All silage should be stored on a concrete base. Do not store pit silage on a hardcore base even if it is very dry silage and was made in ideal conditions.

When cutting silage aim to wilt the grass for 24 hours before ensiling. This will help reduce the volume of silage effluent produced. All effluent should enter the channels under the cover of the silage polythene and the edge of the ensiled grass should not extend onto or over any channel. The open space is maintained by placing a plastic drainage pipe in the channel. Regularly check effluent diversion units, yard gullies or other possible underground escape routes. During the ensiling period, make sure that the effluent is diverted into the underground slurry tank or effluent tank. Make sure that these channels are free of any debris and that the effluent can flow.

Where a suitable wilt is not possible due to wet weather it is advisable to provide additional drainage pipes to help get the liquid away. For example, additional pipes could be laid at the butt of clamp walls or for long clamps; additional pipes could be laid across the pit. These will help relieve the pressure build up from the effluent and reduce the possibility of the pit slipping. To prevent effluent from flowing out over silage walls in the first few days it is important not to pile the grass too high over the walls and to slope the grass back at 45˚ from the top of the walls. All effluent should be collected and channelled into an underground slurry or effluent tank.

When landspreading silage effluent dilute the effluent with one part water/slurry to one part effluent. Do not spread if rain is forecast in the next 24 hours. Do not spread within 5m of any watercourse, 10m where field slope exceeds 10%, 20m from lake/main river or 25 – 200m well/public water supply.

Allowing silage effluent to discharge to a drain or watercourse is an offence under the Local Government (Water Pollution) Act, 1977 as amended by the Local Government (Water Pollution) (Amendment) Act, 1990 and the European Communities (Good Agricultural Practice for the Protection of Waters) Regulations, 2022.

For further information on the Nitrates Regulations or any other queries you may have regarding protecting water quality, please contact the Environment Section of Cavan County Council on 049-4378486 or alternatively at environ@cavancoco.ie