April 21st - 2021

Silage production Part 4

SILO MANAGEMENT

So the grass has been cut at its optimal time, wilted to perfection, chopped at the perfect length and into the trailer. The silo needs to be prepped and ready then filled properly to ensure all the hard work done so far isn’t wasted.

SILO PREPARATION

Build silos and piles on concrete or asphalt pads.

- Walls should be no higher than 6 metres.

Target dimensions of different types of silo.

- The correct sizing of bunkers, clamps and drive-over piles can reduce the risk of an accident.

Walls and floors.

- Walls should be strong enough to withstand the lateral pressure exerted by heavy tractors during silo filling and compaction.
- Joins and cracks should be sealed with bitumen.
- Floors surfaced with hot rolled asphalt withstand corrosive silage acids.
- Rainwater from the surface of unroofed silos should be channelled into separate drains.
- Collection facilities for liquid effluent should be matched to the capacity of the silo.

WALL FILM

Wall film prevents oxygen entering silage at the edges of bunkers and protects walls from corrosion by silage acids.

- Select a Silostop Wall film that is at least 1.5 - 2 metres wider than the height of the silo walls.

- Inspect tops and sides of walls and protect film from sharp objects such as cracked aggregate, stones, metalwork.

- Drape Wall film over the wall so that 1.5 - 2 metres hang down the outside surface. As the silo is filled, the wall film tends to be pulled down and it is important to leave at least 1 metre to overlap the top surface when the silo is full.

- Fold Wall film over on to the top surface then apply the top cover film to ensure water runs off, down outside of Wall film and not into the silage.

FILLING

Aim for high silage density. Match the number of packing tractors and their weight to crop delivery rate to the silo.

- Silage density affects loss of DM. Higher silage densities increase the storage capacity of bunker silos and can decrease the height and footprint of drive-over piles.

- Recommended minimum silage density is 700 to 750 kg fresh weight (FW)/m³ (230 to 250 kg DM/m³).

- High tractor weight is required to achieve sufficient density. But beware of overloading side walls. Check wall load capacity and packing tractor weights before filling.

- Match the number of packing tractors and their weight to crop delivery rate to the silo.

- If forage DM exceeds 40%, packing tractor weight must be increased to reach target silage density.

- Ensure the entire top surface is consolidated as uniformly as possible, paying special attention to the outer edges.

- Bunkers should have a concave top surface during filling and a convex top surface at the end of filling.

Filling silos.

- If forage delivery rate increases, be prepared to add an extra or heavier tractor.

- Estimate likely silage delivery rate to the silo and plan for adequate packing tractor weight. Be prepared to adjust harvesting, filling and packing procedures if necessary.

- Employ well-trained and experienced people, especially those who operate the push-up/blade tractor(s). Provide training as needed.

- Spread forage in uniform layers of 15 cm or less; and pack continuously throughout filling.

- Form a progressive wedge of forage and maintain a slope no steeper than 1 in 3.

- Align the tractor tyre with the track of the previous tractor pass.

- Ensure at least two tractor passes over the surface of each layer of forage.

- Drive-over piles should be packed from side-to-side, as the progressive wedge advances, and the sides of the pile should never exceed a slope of 1 in 3.

- When two or more tractors are used, establish a safe driving procedure.

- When possible, drive up and reverse down packing slopes.

- Do not drive tractors in a circle and avoid making 180o turns on the floor of a bunker or front apron of a pile.

- Increase tractor passes near the walls of bunker silos to increase the density of the forage that is within one metre of the wall.

- Tracked bulldozers and vibrating rollers can be used. Their heavy weight and vibration can achieve higher silage density.

- Tracked vehicles are likely to be more stable on the sloped surface of low DM forages than wheeled loaders. Towed packing devices, including rail wheels and vibrating rollers increase silage density.

Tim Brewer