Machines or tools used to cut or remove unwanted things from the ground, like grass or weeds.
Scarifiers are helpful for making the ground better for plants.
Examples:
The gardener used scarifiers to remove the weeds from the garden.
We need to rent scarifiers to clean up the yard.
The scarifiers made the ground smooth and clean.
The scarifiers worked hard to make the garden nice.
The scarifiers quickly cleaned up the messy ground.
The scarifiers are like big combs for the ground.