**7. Conclusions**

The detrimental effect of air at silage near the surface is a key point to avoid losses of dry matter and quality. To date, no alternative to the use of plastic in covering bunkers or stacks has proven commercially viable for silage producers. Given the widespread use of horizontal silos worldwide, it is vitally important that the film used possesses good oxygen barrier properties as well as good mechanical properties.

In horizontal silos, the plastic needs to be held tightly to the crop. This is usually accomplished with used tires, but many other means can be applied. Besides that, lining bunker walls with plastic improve silage quality along the walls.

The silos' sealing will continue evolving to meet future needs in a conservation of fresh forage, minimize loss and cost, reduce environment contamination, and provide a safe and efficient on-farm feeding system.
