Film layers, bale density and where silage losses come from
Most of the feed lost between the field and the trough is lost to air. Density and wrapping are the two things a baler wrapper controls.
Baled silage keeps because the bacteria in it work without oxygen. Everything that goes wrong with a bale goes wrong because air got in, either because the bale was not dense enough to start with or because the seal failed later.
Density is decided in the chamber
A dense bale contains less trapped air, so the fermentation stabilises faster and the pH falls sooner. Density comes from three things: the chop length going in, the moisture of the material, and the pressure the chamber applies.
Two of those are yours to control before the machine sees the crop. Material chopped to a short, even length packs far better than long material, which is why a chaff cutter in front of the baler changes the result more than most operators expect. Material that is too dry will not compress and too wet will seep.
Film layers
Common practice for baled silage is four layers of stretch film for bales fed within a few months, and six layers where bales are stored longer, stacked, or handled more than once. Each layer costs money, so there is a real trade-off, but a bale that spoils costs more than the film that would have saved it.
Two points matter more than the layer count:
- Overlap. Film is applied with an overlap between passes. If the overlap is set too low to save film, the number of layers on paper is not the number of layers on the bale.
- Time between baling and wrapping. The gap should be as short as you can make it. On the integrated machines, such as the LUC-55 Double-Wrapping model and the LUC-600X, the bale is wrapped in the same cycle, so the gap is close to zero.
Handling and storage
Most film damage happens after wrapping. Bales dragged across stubble, stacked on rough ground, or moved with a spike through the film will let air in regardless of how well they were made. Store bales on a clean, level surface, stack no higher than the film can carry, and check the stack for bird and rodent damage through the season.
What this means for machine choice
If your bales are handled several times, or stored through a long dry season, the two-arm integrated machines are worth the extra cost, because they close the gap between compression and sealing and apply film consistently at every rotation. If bales are fed out quickly and moved once, a single-wrapping machine is enough.
These are general figures from published silage practice. Local crop, climate and storage conditions change them, and your own results over a season are better guidance than any table.
