This is a device used to evenly distribute fertilizer over a large area of land. It is typically pulled behind a tractor or other vehicle and can be adjusted to spread the fertilizer at different rates. It is an essential tool for farmers and gardeners who need to quickly and efficiently spread fertilizer over
From Wikipedia
A broadcast seeder, alternately called a broadcaster, broadcast spreader or centrifugal fertilizer spreader (Europe) or "spinner" (UK), is a farm implement commonly used for spreading seed where no row planting is required, lime, fertilizer, sand, ice melt, etc., and is an alternative to drop spreaders/seeders. Apart from spinners there is also a type of broadcast spreader called "wagtail spreader", used with tractors.