Equipment used to break and loosen the soil to a depth of six to 36 inches (15 to 90 centimeters) may be called primary tillage equipment. It includes moldboard, disk, rotary, chisel, and subsoil plows.
The moldboard plow is adapted to the breaking of many soil types. It is well suited for turning under and covering crop residues. There are hundreds of different designs, each intended to function best in performing certain tasks in specified soils. The part that breaks the soil is called the bottom or base; it is composed of the share, the landside, and the moldboard.When a bottom turns the soil, it cuts a trench, or furrow, throwing to one side a ribbon of soil that is called the furrow slice. When plowing is started in the middle of a strip of land, a furrow is plowed across the field; on the return trip, a furrow slice is lapped over the first slice. This leaves a slightly higher ridge than the second, third, and other slices. The ridge is called a back furrow. When two strips of land are finished, the last furrows cut to leave a trench about twice the width of one bottom, called a dead furrow. When land is broken by the continuous lapping of furrows, it is called flat broken. If the land is broken in alternate back furrows and dead furrows, it is said to be bedded or listed.