A plough or plow () (both pronounced ) is a farm tool for loosening or turning soil before sowing seed or planting. Ploughs were traditionally drawn by oxen and horses but modern ploughs are drawn by tractors. A plough may have a wooden, iron or steel frame with a blade attached to cut and loosen the soil. It has been fundamental to farming for most of history. The earliest ploughs had no wheels; such a plough was known to the Romans as an aratrum. Celtic peoples first came to use wheeled ploughs in the Roman era.
The prime purpose of ploughing is to turn over the uppermost soil, bringing fresh nutrients to the surface while burying weeds and crop remains to decay. Trenches cut by the plough are called furrows. In modern use, a ploughed field is normally left to dry and then harrowed before planting. Ploughing and cultivating soil evens the content of the upper layer of soil, where most plant feeder roots grow.
Ploughs were initially powered by humans, but the use of farm animals is considerably more efficient. The earliest animals worked were oxen. Later, horses and mules were used in many areas. With the Industrial Revolution came the possibility of steam engines to pull ploughs. These in turn were superseded by internal-combustion-powered tractors in the early 20th century. The Petty Plough was a notable invention for ploughing out orchard strips in Australia in the 1930s.
Use of the traditional plough has decreased in some areas threatened by soil damage and erosion. Used instead is shallower ploughing or other less-invasive conservation tillage.
The plough appears in one of the oldest surviving pieces of written literature, from the 3rd millennium BC, where it is personified and debating with another tool, the hoe, over which is better: a Sumerian disputation poem known as the Debate between the hoe and the plough.
Etymology In older English, as in other Germanic languages, the plough was traditionally known by several other names, e.g. Old English (modern dialectal ), Old High German , , , Old Norse (Swedish ), and Gothic , all presumably referring to the ard (scratch plough).
The modern word comes from the Old Norse , and is therefore Germanic, but it appears relatively late (it is not attested in Gothic) and is thought to be a loan from one of the north Italic languages. The German cognate is "Pflug", the Dutch "ploeg" and the Swedish "plog". In many Slavic languages and in Romanian the word is "plug". Words with the same root appeared with related meanings: in Raetic "wheeled heavy plough" (Pliny, Nat. Hist. 18, 172), and in Latin "farm cart", "cart", and "cart box".C. T. Onions, ed., Oxford Dictionary of English Etymology, s.v. "plough" (Oxford: Clarendon Press, 1996).Webster's Encyclopedic Unabridged Dictionary of the English Language, s.v. "plow" (NY: Gramercy Books, 1996). The word must have originally referred to the wheeled heavy plough, common in Roman north-western Europe by the 5th century AD.
Many view plough as a derivative of the verb *plehan ~ *plegan 'to take responsibility' (cf. German pflegen 'to look after, nurse'), which would explain, for example, Old High German pfluog with its double meaning of 'plough' and 'livelihood'.Jaan Puhvel, "The Indo-European and Indo-Aryan plough: a linguistic study of technological diffusion", Technology and Culture 5, no. 2 (1964): 176–190.Jan de Vries, Nederlands Etymologisch Woordenboek, s.v. "ploeg" (Leiden: Brill, 1971).Ruth Schmidt-Wiegand, 'Wörter und Sachen. Zur Bedeutung einer Methode für die Frühmittelalterforschung. Der Pflug und seine Bezeichnungen', in Wörter und Sachen im Lichte der Bezeichnungsforschung (Berlin: B.R.D.; NY: Walter de Gruyter, 1981), 1–41; Heinrich Beck, 'Zur Terminologie von Pflug und Pflügen – vornehmlich in den nordischen und kontinentalen germanischen Sprachen', in Untersuchungen zur eisenzeitlichen und frühmittelalterlichen Flur in Mitteleuropa und ihre Nutzung, eds. Heinrich Beck et al. (Göttingen: Vandenhoeck & Ruprecht, 1980), 2: 82–98. Guus Kroonen (2013)Guus Kroonen, Etymological Dictionary of Proto-Germanic, s.v. "*plōga-" (Leiden: Brill, 2013), 398. proposes a vṛddhi-derivative of *plag/kkōn 'sod' (cf. Dutch plag 'sod', Old Norse plagg 'cloth', Middle High German 'rag, patch, stain'). Finally, Vladimir Orel (2003)Vladimir Orel, A Handbook of Germanic Etymology, s.v. "*plōȝuz" (Leiden: Brill, 2003), 292. tentatively attaches plough to a PIE stem , which supposedly gave Old Armenian "to dig" and Welsh "crack", though the word may not be of Indo-European origin.
Parts
The basic parts of the modern plough are: beam hitch (British English: hake) vertical regulator coulter (knife coulter pictured, but disk coulter common) chisel (foreshare) share (mainshare) mouldboard
Other parts include the frog (or frame), runner, landside, shin, trashboard, and stilts (handles).
On modern ploughs and some older ploughs, the mould board is separate from the share and runner, so these parts can be replaced without replacing the mould board. Abrasion eventually wears out all parts of a plough that come into contact with the soil.
History
Hoeing
When agriculture was first developed, soil was turned using simple hand-held digging sticks and hoes. These were used in highly fertile areas, such as the banks of the Nile, where the annual flood rejuvenates the soil, to create drills (furrows) in which to plant seeds. Digging sticks, hoes and mattocks were not invented in any one place, and hoe cultivation must have been common everywhere agriculture was practised. Hoe-farming is the traditional tillage method in tropical or sub-tropical regions, which are marked by stony soils, steep slope gradients, predominant root crops, and coarse grains grown at wide intervals. While hoe-agriculture is best suited to these regions, it is used in some fashion everywhere.
Ard
Some ancient hoes, like the Egyptian mr, were pointed and strong enough to clear rocky soil and make seed drills, which is why they are called hand-ards. However, domestication of oxen in Mesopotamia and the Indus Valley Civilisation, perhaps as early as the 6th millennium BC, provided mankind with the draft power needed to develop the larger, animal-drawn true ard (or scratch plough). A ploughed field, from BCE, was also discovered at Kalibangan, India.Lal, BB (2003). Excavations at Kalibangan, the Early Harappans, 1960–1969. Archaeological Survey of India. pp. 17 and 98 A terracotta model of the early ards was found at Banawali, India, giving insight into the form of the tool used. The ard remained easy to replace if it became damaged and easy to replicate.
The earliest was the bow ard, which consists of a draft-pole (or beam) pierced by a thinner vertical pointed stick called the head (or body), with one end being the stilt (handle) and the other a share (cutting blade) dragged through the topsoil to cut a shallow furrow suitable for most cereal crops. The ard does not clear new land well, so hoes or mattocks had to be used to pull up grass and undergrowth, and a hand-held, coulter-like ristle could be made to cut deeper furrows ahead of the share. Because the ard left a strip of undisturbed earth between furrows, the fields were often cross-ploughed lengthwise and breadth-wise, which tended to form squarish Celtic fields.Lynn White Jr., Medieval Technology and Social Change (Oxford: University Press, 1962) The heavy soils of Northern Europe were difficult to work with a scratch plough.:43 In fact, the ard is best suited to loamy or sandy soils that are naturally fertilised by annual flooding, as in the Nile Delta and Fertile Crescent, and to a lesser extent any other cereal-growing region with light or thin soil.
Mould-board ploughing
To grow crops regularly in less-fertile areas, it was once believed that the soil must be turned to bring nutrients to the surface. A major advance for this type of farming was the turn plough, also known as the mould-board plough (UK), moldboard plow (U.S.), or frame-plough. A coulter (or skeith) could be added to cut vertically into the ground just ahead of the share (in front of the frog), a wedge-shaped cutting edge at the bottom front of the mould board with the landside of the frame supporting the under-share (below-ground component). The heavy iron moldboard plough was invented in China's Han Empire in the 1st and 2nd century, and from there it spread to the Netherlands, which led the Agricultural Revolution. The mould-board plough introduced in the 18th century was a major advance in technology.
The upper parts of the frame carry (from the front) the coupling for the motive power (horses), the coulter, and the landside frame. Depending on the size of the implement, and the number of furrows it is designed to plough at one time, a fore-carriage with a wheel or wheels (known as a furrow wheel and support wheel) may be added to support the frame (wheeled plough). In the case of a single-furrow plough there is one wheel at the front and handles at the rear for the ploughman to maneuver it.
When dragged through a field, the coulter cuts down into the soil and the share cuts horizontally from the previous furrow to the vertical cut. This releases a rectangular strip of sod to be lifted by the share and carried by the mould board up and over, so that the strip of sod (slice of the topsoil) that is being cut lifts and rolls over as the plough moves forward, dropping back upside down into the furrow and onto the turned soil from the previous run down the field. Each gap in the ground where the soil has been lifted and moved across (usually to the right) is called a furrow. The sod lifted from it rests at an angle of about 45 degrees in the adjacent furrow, up the back of the sod from the previous run.
A series of ploughings run down a field leaves a row of sods partly in the furrows and partly on the ground lifted earlier. Visually, across the rows, there is the land on the left, a furrow (half the width of the removed strip of soil) and the removed strip almost upside-down lying on about half of the previous strip of inverted soil, and so on across the field. Each layer of soil and the gutter it came from forms a classic furrow. The mould-board plough greatly reduced the time needed to prepare a field and so allowed a farmer to work a larger area of land. In addition, the resulting pattern of low (under the mould board) and high (beside it) ridges in the soil forms water channels, allowing the soil to drain. In areas where snow build-up causes difficulties, this lets farmers plant the soil earlier, as the meltwater run-off drains away more quickly.
Parts There are five major parts of a mouldboard plough: Mouldboard Share Landside (short or long) Frog (sometimes called a standard) Tailpiece
The share, landside and mould board are bolted to the frog, which is an irregular piece of cast iron at the base of the plough body, to which the soil-wearing parts are bolted.
The share is the edge that makes the horizontal cut to separate the furrow slice from the soil below. Conventional shares are shaped to penetrate soil efficiently: the tip is pointed downward to pull the share into the ground to a regular depth. The clearance, usually referred to as suction or down suction, varies with different makes and types of plough. Share configuration is related to soil type, particularly in the down suction or concavity of its lower surface. Generally three degrees of clearance or down suction are recognised: regular for light soil, deep for ordinary dry soil, and double-deep for clay and gravelly soils.
As the share wears away, it becomes blunt and the plough will require more power to pull it through the soil. A plough body with a worn share will not have enough "suck" to ensure it delves the ground to its full working depth.