Bunker (Horizontal) Silo Forage Capacity
The forage a horizontal bunker or trench silo holds.
Example
You enter
- Bottom width (ft) 30
- Top width (ft; = bottom for vertical walls) 30
- Average settled depth (ft) 8
- Length (ft) 100
- As-fed density (lb/ft³) 44
You get
- Forage capacity 528 tons as fed
- Volume 24000
Details, formula, and sources
The trapezoidal cross-section (bottom + top)/2 x average settled depth, times length, times as-fed density, over 2,000 lb/ton. A 30 ft wide, 8 ft deep, 100 ft bunker at 44 lb/ft^3 holds about 528 tons. Enter equal bottom and top widths for vertical walls, a wider top for sloped. As-fed density is an input (corn silage ~40-50 lb/ft^3); use the settled depth. A core or weigh-back governs the real inventory.
cross_section = (bottom_width + top_width)/2 x average_depth; volume = cross_section x length; tons = volume x density / 2000.
Horizontal (bunker/trench) silo sizing per NRCS / MWPS (Midwest Plan Service) forage storage references, by name; trapezoidal-prism geometry.
The trapezoidal-prism volume and the tons = volume x density / 2000 relation are public; forage density references are extension-published.
Estimate. AHJ and licensed professional govern.
Field names used by the API: bottom_width_ft, top_width_ft, average_depth_ft, length_ft, density_lb_ft3, tons, volume_ft3
- Cross-section trapezoid (bottom + top)/2 x average settled depth; vertical walls = equal widthsbunker geometry
- As-fed density user-entered; corn silage ~40-50 lb/ft^3, varies with dry matter and packingNRCS / MWPS forage references
- Settled depth use the depth after packing, not the fill heightforage-storage practice