The plough (American spelling: plow; both ) is a tool used in farming for initial cultivation of soil in preparation for sowing seed or planting. It has been a basic instrument for most of recorded history, and represents one of the major advances in agriculture. The primary purpose of ploughing is to turn over the upper layer of the soil, bringing fresh nutrients to the surface, while burying weeds and the remains of previous crops, allowing them to break down. It also aerates the soil, and allows it to hold moisture better. In modern use, a ploughed field is typically left to dry out, and is then harrowed before planting.

Ploughs were initially pulled by oxen, and later in many areas by horses. In industrialised 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mechanical means of pulling a plough used steam-power (ploughing engines or steam tractors), but these were gradually superseded by internal-combustion-powered tractors. In the past two decades plough use has reduced in some areas (where soil damage and erosion are problems), in favour of shallower ploughing and other less invasive tillage techniques.

Ploughs are even used under the sea, for the laying of cables, as well as preparing the earth for side-scan sonarFact: date=November 2007 in a process used in oil exploration.

Etymology

In English, as in other Germanic languages, the plough was traditionally known by other names, e.g. Old English sulh, Old High German medela or huohili, and Old Norse arðr.

The current word plough also comes from Germanic, but it appears relatively late (it is absent from Gothic), and is thought to be a loanword from one of the north Italic languages. In these it had different meanings: in Raetic plaumorati (Pliny), and in Latin plaustrum "wagon, cart", plóstrum, plóstellum "cart", and plóxenum, plóximum "cart box".

The word first appears in Germanic as Lombardic plóvum. This term was borrowed into Balto-Slavic languages, such as Old Church Slavonic plugъ and Lithuanian plúgas. Ultimately, the word is thought to derive from an ancestral PIE *blōkó, related to Armenian pelem "to dig" and Welsh bwlch "gap, notch".

Hoeing

Main: Hoe-farming 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