Which three items should be checked before starting calibration?

Before starting calibration, it is crucial to ensure that all equipment is in proper working order to guarantee the effective application of herbicides. Checking the nozzle tips, pump, and all connections helps confirm that there are no clogs, leaks, or other issues that could affect application efficiency and uniformity.

Nozzle tips must be inspected to make sure they are not worn or damaged, as this impacts the spray pattern and droplet size. A malfunctioning pump could result in inadequate pressure or flow, leading to uneven application of the herbicide. Additionally, ensuring all connections are secure and free from leaks is essential to maintaining consistent pressure and preventing any loss of materials during the process.

The other options, while they include relevant items, do not comprehensively cover the foundational checks necessary for calibration. For instance, focusing solely on pesticide type, water source, and pressure gauge does not directly address the working components of the spraying equipment itself. Similarly, while spray pattern, weather conditions, and nozzle tips are important considerations for effective spraying, they are not items that need to be checked for calibration readiness directly in terms of equipment functionality.