Chemical Application Rate (GPA)
The gallons per acre a sprayer applies, or the nozzle flow (GPM) that hits a target rate at the entered speed...
Example
You enter
- Nozzle GPM 0.4
- Nozzle spacing (in) 20
- Ground speed (mph) 5
- Target GPA (optional) 25
You get
- GPA 23.76 gal/acre
- Required GPM for target 0.421
Checked against published worked examples from: Mississippi State University Extension.
Details, formula, and sources
ScopeThe gallons per acre a sprayer applies, or the nozzle flow (GPM) that hits a target rate at the entered speed and spacing. GPA = (5940 * GPM) / (speed * spacing) and inverse for target GPA.
Formula or tableGPA = (5940 × GPM) / (speed_mph × spacing_in). The constant 5940 = 60 min/hr × 43,560 ft²/acre × 12 in/ft / 5,280 ft/mi = 5,940.
Source and editionASABE EP367 (Guide for Preparing Field Sprayer Calibration Procedures) by name; manufacturer sprayer-calibration guides (John Deere, AGCO, Case IH) by name.
Free accessASABE standards licensed; calibration principles free at most state-extension service pages (e.g., extension.psu.edu).
What governsRead and follow the product label. The label is the law (FIFRA).
API field namesgpm, spacing_in, speed_mph, target_gpa, gpa, required_gpm
- Constant 5940 60 min/hr x 43,560 ft2/acre x 12 in/ft / 5,280 ft/mi: converts gal/min per nozzle at mph and inches of spacing to gal/acreunit conversion; extension calibration guides