Pesticide Application Equipment and Spray Technology
Pesticide Application Equipment and Spray Technology
This domain tests sprayer types, nozzle selection, calibration, droplet size and drift management. Expect numerical calibration and practical equipment faults.
Core rules
- A knapsack hydraulic sprayer uses a lever or piston pump, pressure gauge, filter, lance and nozzle. Keep pressure within the label range.
- Flat-fan nozzles suit broadcast herbicide spraying; hollow-cone nozzles suit insecticide and fungicide coverage; full-cone nozzles suit soil-directed sprays.
- Fine droplets increase drift; coarse droplets increase runoff. Match droplet size to target and weather.
- Calibration formula: L/ha = (nozzle flow in L/min x 600) / (speed in km/h x swath in m).
- Check nozzle wear, filters and pressure gauge before each spray; clean the sprayer after use.
Worked example
A nozzle flows 1.2 L/min, the sprayer travels at 3 km/h and the swath is 0.5 m. Reasoning: L/ha = (1.2 x 600) / (3 x 0.5) = 720 / 1.5 = 480 L/ha. If the label requires 400 L/ha, adjust speed, pressure or nozzle size and recalibrate.
Traps
Calibrating with water but changing product, using a worn nozzle, spraying in wind above the label limit, and measuring swath incorrectly all lose marks.
Key distinction
Pressure changes flow and droplet size; speed changes output per hectare. Calibrate after either change.