Which of the following is not a way to calibrate a sprayer effectively?

Calibrating a sprayer effectively is crucial for ensuring that the right amount of pesticide is applied to the target area. The correct answer indicates that estimating based on previous applications is not a reliable calibration method.

Using a stopwatch to time the application provides precise data on how long it takes to spray a certain area, allowing for more accurate calculations of the pesticide application rate. Changing nozzle type and pressure is fundamental as these factors directly affect the droplet size and distribution, which can influence effectiveness and safety. Additionally, measuring the output in the field provides concrete data on how much product the sprayer is delivering, which can be assessed against the intended application rate.

In contrast, estimating based on previous applications does not take into account changes in equipment performance, environmental conditions, or variations in field conditions. This method lacks the precision needed for accurate calibration and could lead to under- or over-application, potentially resulting in ineffective pest control or harm to the environment. Therefore, relying on estimation rather than direct measurement and testing does not ensure the sprayer is calibrated effectively.