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The plough (American spelling: plow) is a tool used in farming for initial cultivation of soil in preparation for sowing seed or planting. Ploughs are also used by industry underseas, for the laying of cables, as well as preparing the earth for side-scan sonar in a process used in oil exploration.
The plough can be regarded as a development of the pick, or of the spade. Ploughs were initially pulled by humans, later by oxen, and later still in some countries, by horses. In industrialized countries, the first mechanical means of pulling a plough used steam-power (ploughing engines or steam tractors), but these were gradually superseded by internal-combustion-powered tractors.
Ploughing has several beneficial effects. The major reason for ploughing is to turn over the upper layer of the soil. This may also incorporate the residue from the previous crop into the soil. Ploughing reduces the prevalence of weeds in the fields, and makes the soil more porous, easing later planting. Excessively deep ploughing or digging brings up subsoil and mixes subsoil with topsoil. This can damage the soil.
The early German word before sound-shift is plug and in Old Prussian plugis. After the German sound shift (p = pf) it became the modern German word Pflug.
History of the plough
Hoeing
When agriculture was first developed, simple hand held digging sticks or hoes would have been used in highly fertile areas, such as the banks of the Nile where the annual flood rejuvenates the soil, to create furrows wherein seeds could be sown. In order to regularly grow crops in less fertile areas, the soil must be turned to bring nutrients to the surface.
Scratch plough
The domestication of oxen in Mesopotamia, perhaps as early as the 6th millennium BC, provided mankind with the pulling power necessary to develop the plough. The very earliest ploughs were simple scratch-ploughs and consisted of a frame holding a vertical wooden stick that was dragged through the topsoil. Because this form of plough leaves a strip of undisturbed earth, according to Lynn White, "cross-ploughing is necessary, with the result that, in regions where the scratch-plough is used, fields tend to be squarish in shape, roughly as wide as they are long."In the archeology of northern Europe, these squarish fields are referred to as "Celtic fields". |
The traditional way: a German farmer works the land with a horse and plough.
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Mouldboard plough
These were much later developed into mouldboard ploughs (American spelling: moldboard), which is a form of plough consisting of a plowshare (blade) and hitch attached to either a tractor or livestock. It turns the soil in one run across the field, depositing the weeds and undecomposed remains of the previous crop under the soil and raising the rain-percolated nutrients back to the surface. This plough also allowed for ploughing while the ground was wet. The water was drained due to channels formed under the overturned earth.
The French historian Marc Bloch, whose pioneering work contributed to our distinction between the scratch and mouldboard ploughs, emphasizes the difference between the two on the basis of having wheels. His research in medieval French agricultural history showed the existence of names for two different ploughs, "the araire was wheel-less and had to be dragged across the fields, while the charrue was mounted on wheels".
The mouldboard, carried below the frame, is tipped with a share (also called a ploughshare), an asymmetric arrow-shaped device designed to slice through the ground horizontally as it moves forward. It also has a coulter, a sharpened blade or disc, attached to the frame of the plough to cut down through the ground, ahead of the share, and also to cut deepset and tough roots. A runner extending from behind the share to the rear of the plough controls the direction of the plough, because it is held against the bottom land-side corner of the new furrow being formed. The holding force is the weight of the sod, as it is raised and rotated, on the curved surface of the moldboard. Because of this runner, the mouldboard plough is harder to turn around than the scratch plough, and its introduction brought about a change in the shape of fields -- from mostly square fields into longer rectangular "strips" (hence the introduction of the furlong).
It was originally designed for "sod busting": the reclaiming of raw land and creation of farmland. However, until the past two decades it was routinely used even on previously tilled land, in the Midwest of the United States and elsewhere. Awareness of the potential for soil damage has led to reduced use in favour of shallower ploughing and other less invasive tillage techniques.
Despite a number of innovations, the Romans never achieved the heavy wheeled mouldboard plough; Lynn White dates its first indisputable appearance after the Roman period to 643, in a northern Italian document. On the other hand, White describes the linguistic researches of B. Bratanič of the University of Zagreb, who showed that twenty-six technical terms connected with the heavy plough and its use "are to be found in all three of the great Slavic lingusistic groups, the eastern, western and southern", pointing to its adoption by these people before their division in the later sixth century, and indicating that the mouldboard plough was invented by 600 then introduced to Europe. Despite this, "Bratanič does not claim the invention of the heavy plough for the Slavs, but for 'some northern peasant culture' as yet unidentified." It appears to have been independently developed in Han Dynasty China, around 100 BC. Despite the date or place of its origins, White argues that adoption of the mouldboard plough, accompanied with adoption of the three-field system, occurred in the later eighth and early ninth centuries, and led to an improvement of the agricultural productivity per unit of land in northern Europe.
The Girard (or Gerard) plough was developed in the early 14th century in what is now Belgium by Girard de Liege. It was the first plough design to have an iron blade.
The first commercially successful iron plough was the Rotherham plough, developed by Joseph Foljambe in Rotherham, England, in 1730. It was durable and light, and was engineered after the mathematical principles of James Small, who designed a mouldboard that would cut, lift and turn over the strip of earth. (All the major components of the Rotherham plough had been well known in China for millennia, and diffusion of technology from China, probably by the Dutch, is highly likely)
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