Plow | Description, History, Types, & Facts - Encyclopedia Britannica

Plow types

In its simplest form the moldboard plow consists of the share, the broad blade that cuts through the soil; the moldboard, for turning the furrow slice; and the landside, a plate on the opposite side from the moldboard that absorbs the side thrust of the turning action. Horse-drawn moldboard plows, which are no longer commonly used, have a single bottom (share and moldboard), while tractor-drawn plows have from 1 to 14 hydraulically lifted and controlled bottoms staggered in tandem. Listers and middlebusters are double-moldboard plows that leave a furrow by throwing the dirt both ways.

More From Britannica agricultural technology: Primary tillage equipment

Disk plows usually have three or more individually mounted concave disks that are inclined backward to achieve maximum depth. They are particularly adapted for use in hard, dry soils, shrubby or bushy land, or on rocky land. Disk tillers, also called harrow plows or one-way disk plows, usually consist of a gang of many disks mounted on one axle (see harrow). Used after grain harvest, they usually leave some stubble to help reduce wind erosion and often have seeding equipment. Two-way (reversible) plows have disks or moldboards that can be either opposed, so that one fills the trench made by the other, or set to throw the soil entirely to the right or left.

Rotary plows or tillers (sometimes called rototillers) have curved cutting knives mounted on a horizontal power-driven shaft. The pronged rotary hoe, a plow used chiefly for seedbed and weed control, works well at high speed. Garden sizes cut swaths from about 0.3 to 0.8 metre (1 to 2.5 feet) wide; tractor types, more than 3 metres (10 feet).

Also spelled: plough (Show more) Key People: John Deere (Show more) Related Topics: bottom steam-hauled plow subsoil plow furrow disk plow (Show more) See all related content

Deep tillage implements, used chiefly to break up hardpan and packed soils, include the subsoiler and the chisel plow. The subsoiler must be pulled by a heavy tractor, for its steel-pointed shank is capable of penetrating the subsoil to a depth of nearly one metre (three feet). The chisel plow, or ripper, has several rigid or spring-toothed shanks with double pointed shovels mounted on a transverse bar at intervals of 0.3 to 0.9 metres (one to three feet). Plowing depths vary from shallow to a half metre (1.5 feet).