How Much Grain Do You Have Stored?
Grain handlers, processors, and farmers are frequently required to determine the inventory of corn, soybeans, wheat, and other products in various sized storage structures. This task is complex because granular products compress when pressure is applied to them during filling. The material at the bottom of a storage bin will be compressed by the weight of the material above it, and this packing effect increases the capacity. Test weight, moisture content, bin dimensions, broken grain and foreign material, and other variables will change the packing value of stored grain.
The spreadsheet and instruction manual (example farm in PowerPoint) will allow for a farmer to enter weights (obtained from scales or yield monitors) and compare the results to in bin measurements. The in bin measurements are based on procedures from USDA FSA/RMA to estimate the number of bushels stored in a bin. This procedure is not an exact match to the USDA method, although it should be within 1-2%. A producer should also keep in mind that there are potentially significant errors in determining grain inventory; marketing grain based on these measurements should be used with care.
You are free to download the following PowerPoint file for the instructions and then enter data for an example farm in the Excel file. This will allow you to compare the number of bushels of grain stored compared to scale weights (if available).