Measure the pieces of gravel in the field that you want to plow. If they are on average greater than 3 inches in diameter, remove the rocks before plowing. Smaller gravel will move out of the way as your plow cuts through the soil and not clog or damage your equipment.
Attach plow shoes to your snow plow that allow the edge of the plow blade to rest 1 inch off the ground when it is completely lowered. This will prevent you from dragging gravel off of the road and snagging on frozen gravel.
Listen for the sound of gravel against your plow. If the sounds becomes intense, raise the blade a half inch or more if needed.