Glossary · Silage
Silage Density
Pounds of dry matter per cubic foot of silage. The factor that converts pile volume to tonnage, and a leading indicator of fermentation quality.
Silage density is the amount of dry matter packed into a given volume of silage, typically expressed as pounds of dry matter per cubic foot (lbs DM/ft³).
Density matters for two reasons. First, it’s how you convert pile volume to tonnage — without an accurate density, even a perfectly measured pile gives you the wrong number of tons of feed on hand. Second, density is a direct indicator of how well the pile was packed, which is a leading indicator of how much oxygen was excluded during ensiling and how much shrink will happen in storage.
Industry references for dry matter density:
- Bunker silos: 14–16 lbs DM/ft³ when properly packed
- Drive-over piles: 10–13 lbs DM/ft³
- Ag bags: 15–17 lbs DM/ft³
Density isn’t uniform within a pile. It’s highest at the bottom (compressed by overlying weight) and lowest at the top. Sampling at multiple depths gives a more accurate average than a single face core.
Higher density = better fermentation = less shrink. Density measurement is one of the most actionable diagnostic measurements on a silage operation.