Which of the following statements about granular applicators is true?

• A. Drop spreaders drop granules by gravity below the feed-gate opening
• B. Drop spreaders are popular for broadcast application over large areas
• C. Granular applicators should be recalibrated whenever the temperature changes
• D. Rotary spreaders are best used along hard surfaces

Answer: (C)

Recalibrating when temperature changes is essential because the flow of granular material through a spreader isn’t fixed once you set it. Temperature can alter how granules behave as they move through the metering system and out the discharge opening. Moisture content, granule clumping, and changes in friction inside the hopper or feed mechanism can cause more or less material to be released in a given period. If you don’t recheck and adjust the calibration, the actual rate applied per area can drift away from your target, leading to under- or over-application.

In practice, you’d perform a quick calibration test under current conditions (measure how much material is dispensed over a known area) and adjust the setting to hit the desired rate. This keeps the application precise despite changing temperature. The other statements describe general use cases of different spreader types, but they don’t address why adjusting calibration for temperature is necessary.