Your drone flight measures volume very precisely — but volume alone is not tonnage. Density is the bridge: volume × density = tons. Getting density right is the single biggest factor in how accurate your inventory numbers are.
As-fed vs. dry-matter density
Each record can carry two density values:
- As Fed Density — the weight of the feed as it sits in the pile, water included (lbs/ft³ or kg/m³).
- Dry Matter Density — the weight of just the dry matter portion.
The two are linked through Dry Matter %: dry-matter density is as-fed density × DM% ÷ 100. When you toggle the Inventory page between As Fed and Dry Matter, SilagePlan uses the matching density to compute tons on that basis. If one basis is missing for some locations, the page will tell you and the toggle stays limited until it is filled in.
Where a density value comes from
Each density carries a badge showing its source, in order of precedence:
- override — a value you typed on the record yourself. It takes precedence over everything, so use it when you have scale data or a nutritionist’s measurement you trust. (An Override Note column lets you record why.)
- avg — Average Density, a weighted average of the densities calculated from your own flight history.
- calc — Calculated Density derived from your feed-out data: when SilagePlan knows the tons fed between flights and the drone measured the volume that disappeared over the same period, it can derive the real packed density of that feed. On the classic Inventory page you produce these by clicking a feed row and entering Used Tons; in Inventory V2, used tons live in the forecast tool.
- assumed — a standard starting value used until real data exists.
Over time, calculated densities from regular flights and feed-out entries tend to be the most accurate, because they reflect how your feed is actually packed.
Getting good density numbers
Silage density varies widely from farm to farm — crop, moisture at harvest, chop length, packing weight, and pile height all change it, and every error in density is passed straight through to your tonnage. We recommend:
- Fly regularly so volume changes between flights are well measured.
- Record used tons from your feed software or scale between flights.
- Let SilagePlan calculate density per location, and review Average Density per feed type.
- Only enter a manual density when you have a measured value you trust more.
For research-backed packing-density benchmarks and what they mean for dry-matter loss, see the Packing density & shrink section on the Inventory V2 page — it shows where each pile sits on the density-vs-loss curve and the practices that improve it. More in Tracking shrink.
Where density shows up
- The density columns of the inventory data table — Density, Calculated Density, and Average Density, each in AF and DM variants in Inventory V2, plus a Density Source column.
- Total tons and Total Inventory values (both As Fed and Dry Matter).
- Runout dates — wrong density means wrong tons, which means wrong runout.
- Shrink analysis, where declining dry-matter density signals loss — see Tracking shrink between flights.
For a visual walkthrough, watch the density video tutorial.