What must you measure to calibrate granular application equipment?

To calibrate granular application equipment effectively, measuring the weight of the granules spread over a known area is essential. This measurement provides critical information on how much product is being applied per unit area, which is vital for ensuring that applications meet the manufacturer's recommendations and effectively control pests.

When calibrating, the goal is to ensure that the spreader uniformly distributes the appropriate amount of granules to achieve the desired application rate. By weighing the amount of granules that falls within a specified area, you can assess whether the spreader is functioning correctly and if adjustments are needed to either the spreader settings or the ground speed.

The other options, while relevant to the operation or functionality of the granular application equipment, do not directly influence the calibration process in the same way. For instance, measuring the ground speed of the spreader can be useful for understanding how quickly an application is made, but it does not provide a direct measurement of the actual product application rate related to pest control effectiveness. The amount of granules placed in the spreader is necessary for operational setup, but without measuring how much is applied over a specific area, it does not contribute to aligning the application with required rates. Lastly, the type of granular material used can affect application characteristics, but it