Silage may be made in pits dug in the ground, clamps or heaps, silage towers, or wrapped in plastic.
Pits and clamps.Rough terrain fork trucks, front-end loaders or buckrakes can be used to fill silage pits or build clamps. Loading and consolidating silage, especially when building an above-ground clamp, has certain dangers. Never drive close to the edge when consolidating the clamp. Wide track settings will increase the stability of the tractor. Dual rear wheels are a useful aid to safe and effective consolidation of silage.
Towers.Although expensive to install, towers make complete mechanization of silage making and feeding possible. Reinforced concrete or coated steel sheets are used to construct tower silos. Silos with diameters of up to 10 m are in common use, with heights ranging from 9-24 m.
Plate 15.10 A forage wagon picks up, chops and loads a swath in a single operation. A chain and slat floor conveyor unloads the wagon from the rear after opening the tailgate. (Claas)
A dump box or forage box, combined with a blower, is generally used to fill the tower. The dump bo Sis a large hopper on wheels with a floor conveyor to carry the material to a discharge chute at the back of the hopper. A forage box is a self-emptying trailer with high sides; it can be towed by a tractor alongside a forage harvester. The blower is a high output fan, driven by a tractor or an electric motor, which fills the tower by blowing the crop up a duct into the filling hatch.
Grass is tipped into the dump box from trailers and then fed to the blower. Forage boxes discharge the crop into the blower. Some blowers have a chopping unit to cut the material into short lengths before blowing. In any case, green material stored in tower silos must be chopped into short lengths. Long material would be extremely difficult to remove from the tower.
After filling, the tower must be sealed to keep out the air. Provision is made to prevent a build-up of pressure on hot days with an expansion valve or breather bag. Air is excluded from the tower to remove oxygen which is undesirable in the silage making process. Never enter a silage tower as soon as it has been opened; it must be left open to allow oxygen in before anyone is permitted to go inside the tower.
The green material is chopped before it is blown into the tower to make mechanical unloading possible. This can be with a top or bottom unloader. Top unloaders have a series of digging teeth on an endless chain which cut and carry the silage to a blower unit at the centre of the unloader. A chute from the blower throws the silage through an opening in the side of the tower into a duct. From here, it falls to ground level where a conveyor can take the silage to the livestock. The cutting mechanism moves round on top of the silage; it has its pivot and electric motor drive at the centre of the unloader. As the level of silage falls, the unloader is lowered. It is supported from the top of the tower by chains attached to the roof.
A bottom unloader also has a cutting mechanism and conveyor. It is placed in an opening at the base of the tower. The silage gradually moves downwards as the tower is emptied. The unloader can be withdrawn from the tower for maintenance or repairs.
Plastic bags.Silage can be made by sealing the forage in plastic bags. Earlier methods involved placing the bale in a large black plastic bag or continuous plastic tube and sealing the ends to exclude the air for the fermentation process. This is a useful system for small-scale silage making, especially if half-size bales are made with a conventional baler.
Plate 15.11 This bale wrapper is suitable for round bales up to 1.3 m diameter or square bales up to 1.8 m long with sides to a maximum of 0.8 m. The bale is turned in various directions by the platform belts while it is wrapped with several layers of plastic film. (Overum)