plough

A plough is a tillage implement drawn through soil by animal or machine power, designed to cut, lift, and invert earth to depths typically between 150 mm and 300 mm. The inverted soil buries weeds, crop residue, and pests while exposing fresh earth for seed placement. The implement consists of a frame, one or more ploughshares (cutting blades), and a mouldboard that angles the soil away from vertical.

The mouldboard shape is critical to plough function. A gentle curve produces a rough inversion suitable for heavy clay; a tighter spiral roll moves soil faster and works better in lighter loams. Ploughshares are typically made from forged steel and wear quickly in abrasive soils, necessitating regular replacement. The depth of cut is controlled by an adjustable wheel or skid running behind the implement, and the width of cut (usually 200 mm to 400 mm per body) determines how many furrows are made in a single pass.

Two main types dominate modern use. Moldboard ploughs, also called turning ploughs, completely invert the soil and are the standard for deep cultivation. Disc ploughs use concave steel discs instead of a mouldboard and excel in stony or sticky ground where a traditional ploughshare would jam or break. Reversible ploughs allow the working parts to flip from one side of the frame to the other, reducing the need to return the implement to the starting edge after each pass.

Working conditions and wear

Plough performance depends heavily on soil moisture. In wet clay, soil adheres to the mouldboard and clogs the furrow; in dry, compacted earth, draft resistance rises sharply and stone strikes can shatter hardened steel. Optimum conditions exist in a narrow window when soil crumbles but does not stick. Rocky ground damages the share and can bend the frame; fields must be cleared of large stones before ploughing or the implement will spend more time being repaired than working.

The term 'plough' derives from Old English and is spelled this way in Commonwealth usage; American English standardized to 'plow' in the 19th century. Modern ploughing is no longer universal practice in commercial farming, having given way to reduced-till and no-till systems in many regions, but it remains essential for field renovation, breaking compacted layers, and incorporation of organic matter in regenerative and organic agriculture.