How do you calculate per-acre application rate during calibration of a ground spray rig?

• A. Use a fixed per-acre rate regardless of sprayer settings.
• B. Determine nozzle discharge rate (GPM) and swath width; measure vehicle speed (mph); use rate = (GPM x 96.3 x mph) / swath width; adjust accordingly.
• C. Only measure swath width
• D. Calibrate by counting nozzle drips

Answer: (B)

The main idea is that the amount applied per acre comes from how much liquid the sprayer puts out each minute and how much area that minute covers. To get gallons per acre you blend the nozzle flow (gallons per minute), how wide the spray swath is (feet), and how fast you’re moving (miles per hour). The standard calibration uses a formula that combines these three factors: rate = (GPM × 96.3 × mph) ÷ swath width. The 96.3 is a conversion factor that makes the units line up so the result is gallons per acre. By measuring or setting the nozzle output, the speed, and the swath, you can calculate the per-acre rate and then adjust nozzle size, pressure, or speed to hit the target. Using a fixed rate ignores changes in sprayer settings, measuring only swath width misses the flow component, and counting nozzle drips is too imprecise for reliable calibration.