Application Equipment and Calibration
Core concepts
Calibration ensures the correct amount of product is applied per unit area. Know the basic formula: application rate = (flow rate × time) / area, and the common calibration methods for sprayers (measuring output over a known distance and swath). Understand nozzle types (flat fan, hollow cone, full cone, air induction), droplet size, and drift potential. Know how pressure, speed, and nozzle size affect output. Understand the difference between broadcast, banded, directed, and spot applications. Master the concepts of tank mixing, compatibility, and the order of mixing (fill tank partway, add products in the correct order, agitate).
Traps to expect
Questions often test whether you know that doubling speed halves the rate per acre, or that increasing pressure increases flow and drift. Don't confuse nozzle wear (which increases output) with clogging. Watch for tank-mix order questions: always follow label order, and never mix incompatible products. Also expect questions on rinsing and triple-rinsing containers.
Worked example / rule of thumb
Rule of thumb: calibrate before each season and whenever you change nozzles, pressure, or speed. Example: if a sprayer applies 20 GPA at 4 mph and you double speed to 8 mph, the rate drops to about 10 GPA - you must recalibrate or adjust pressure/nozzle to restore the target rate. Always check nozzles for wear; worn nozzles over-apply.