What is a disc (farming) used for?

Question

as in a Big G Disc

Answer 1

Tilling the soil, readying it for planting.

Answer 2

Where A plow turns the soil over ,the disk cuts and chops and leaves a seedbed with enough (trash)corn stalks,bean stems etc. to allow capillary action to work better ;Water soaking deeper after a rain then moving toward the surface when the sun comes out.

That is the theory as explained to me.

Answer 3

Simply put, to break up and aeriate the soil.

Answer 4

The disc is used to till groves in the soil so your seed has a bed before you cover it over.