Linked from
The 10 pages that link to Silage, each with the reason it gives.
ForageRelated: Silage preserves forage when drying it into hay is impractical.
RumenRelated: Silage is a common feed whose composition affects rumen fermentation.
HarvestRelated: Harvested forage can be chopped and stored as silage.
Formic acidRelated: Formic acid can suppress undesirable fermentation during silage production.
AlfalfaRelated: Alfalfa can be ensiled, often with other forage crops, for livestock feed.