Wet silage in the pit: What to do and how to handle it

Some farmers making pit silage across the country this week found themselves in a situation where grass was mowed and – as a result of heavy rain – was left lying.

Based in Teagasc Kildalton, Tom Ryan has offered advice to farmers who find themselves in a situation similar to this.

Ryan outlined that wet grass has the potential to release up to 350L of effluent per tonne.

However, the farm management specialist explained that as grass gets more stemmy, the volume of effluent released per tonne will reduce, especially if weather conditions improve.

Silage bases

With silage bases, Ryan stressed that every effort should be made to confine the width of the clamp to the space between the channels.

He warned that if material is placed out over the channels or slips out past the channels then effluent will escape.

Kiely Malone silage contractor

Where silage crops have grown heavier than usual, many farmers will be forced to extend them out past the front channel, he noted.

In this case, Ryan suggested that a temporary kerb should be used to contain the spread of effluent over the concrete at the front of the pit and divert it to the storage tank.

Separating rain from effluent

If rain falling on the yard in front of the pit is allowed to mix with the effluent, it will boost the volume of effluent that has to be handled.

He explained that it will also do more damage to the yard surface and create smells.

Grass, silage, Dovetails

The rainwater from the silage pit cover should be, if at all possible, diverted away from the effluent storage tank otherwise, a sudden downpour may overflow the tank.

This can be achieved keeping the kerb close to the pit and by bringing the silage cover out over the temporary kerb.

Where pits have channels these should be used in the normal way by placing a plastic drainage pipe in the channel to form an open space for effluent to get away quickly.

These should take the most of the effluent and reduce the volume of flow at other temporary kerbs used to control the effluent.

Walled pits

In walled pits, the farm management specialist suggested that as well as providing front and rear channels, it is necessary to use drainage pipes at the walls to allow effluent to drain away quickly and relieve effluent pressure on the floor and walls.

If no drainage is used there is a chance that the silage will split and shift forward under the pressure of trapped effluent.

Drainage pipes can either be placed at the butt of the wall or in channels near the wall, if they are provided, he outlined.

Ryan suggested “throwing a shake of straw” over the drainage pipes to help to improve drainage further.