What defines a blower type granular spreader?

A blower type granular spreader is defined by its method of operation, specifically using motor-generated air pressure to propel granules. This technique allows for a more controlled and uniform distribution of granular material over a designated area. The blower mechanism creates airflow that lifts and carries the granules, ensuring they are spread evenly, which is particularly beneficial in managing aquatic pests where precision is important for effectiveness.

In contrast, the other options highlight different methods or characteristics that do not accurately describe a blower type granular spreader. For instance, using mechanical energy to crush granules pertains more to a granulating machine rather than a spreader. Employing gravity to distribute granules refers to traditional gravity-fed spreaders, which rely on weight and slope rather than air pressure. Finally, the statement about only working with liquid herbicides is incorrect because a blower type granular spreader is designed specifically for granular materials, not liquids. Understanding these distinctions is crucial for effectively utilizing equipment in aquatic pest control.