mouldboard

A mouldboard is the curved metal plate on a mouldboard plow that turns over soil after it is cut by the share. The combination of share, mouldboard, and sometimes a coulter enables the plow to slice, lift, and invert a layer of soil to form a furrow slice on the surface.

The mouldboard plow works by cutting a swath of soil with the share and then guiding it with the curved mouldboard so that the soil is turned over and placed to the side or back of the furrow. The amount of inversion depends on the mouldboard’s shape, the plow’s angle of attack, and depth setting. The implement is usually attached to a draft animal or tractor.

Origin and use: The mouldboard plow emerged in the 18th and 19th centuries as an improvement over earlier wooden plows, enabling more efficient tillage of heavier soils. It became the standard for primary tillage in many regions, allowing larger fields to be plowed quickly. Modern farming has reduced reliance on complete inversion through conservation tillage, though mouldboard plows remain in use in some settings.

Variants include reversible or two-way mouldboards that can plow in either direction, and versions with steel or cast-iron mouldboards of varying curvature. While effective at burying crop residues and weeds, the mouldboard plow can contribute to soil erosion and disruption of soil structure if misused or applied on vulnerable landscapes; alternatives such as disk or chisel plows are used for reduced-till regimes.