Disc plows can be classified into two main types based on the disc mounting method: ordinary and vertical. Both ordinary and vertical disc plows have a 10°–30° angle between the rotating plane of the disc and the direction of travel, which serves to push the soil and enhance the disc's ability to penetrate the soil. The rotating plane of an ordinary disc plow is not perpendicular to the ground but slightly inclined, forming an angle between the rotating plane and the vertical line, typically about 30°–45°. The angle of inclination in an ordinary disc plow is represented by the acute angle between the horizontal diameter of the disc and the direction of travel. This angle allows the disc to easily cut into clods and lift them before flipping them. Disc plows generally have a scraper mounted on the upper rear of the concave surface of the disc to prevent soil adhesion. The curved surface of the scraper also assists in turning the clods.
Vertical disc plows have a rotating plane perpendicular to the ground surface, with only an angle of inclination and no tilt. Vertical disc plows have smaller discs, but a single plow can have a large number of discs (large vertical disc plows can have 30-40 discs), primarily used for shallow tillage and stubble removal. They can also be equipped with seed and fertilizer boxes for combined tillage, sowing, and fertilization operations.
Ordinary disc plows also include bidirectional disc plows that can tilt left or right. The plow beam, which mounts the plowstock, can swing horizontally relative to the plow frame to adapt to the disc reversal. The reversing mechanism can be mechanical or hydraulic. Bidirectional disc plows ensure that the soil clods always turn to one side of the field, resulting in a smooth surface without furrows.
Drive-type disc plows were developed in some countries in the 1980s. Driven by the tractor's power take-off shaft, a group of discs rotates at approximately 120 rpm, providing good tillage and soil breaking up. They are particularly effective at utilizing tractor power when tilling wet land or rice stubble fields.
