Since the beginning of history, plowing (also spelled ploughing) has been the most important implement used to turn and break up the soil, bury crop residues, and help control weeds.
The precursor of the plow is the prehistoric digging stick. The earliest plows recorded in history were digging sticks that were fashioned with handles that allowed users to push and pull them. Later in Roman times, light and wheel-less plows with iron shares or blades were pulled by oxen. Though these worked for the Mediterranean regions, they were not effective for the heavier soils of northwestern Europe.
That is when the wheeled plow that was first drawn by oxen then later by horses came to be. It made it possible for the northward spread of European agriculture. The 18th century saw the addition of the moldboard that turned the furrow slice cut by the plowshare; it was an important advancement. In the 19th century, the black prairie soils of the American Midwest challenged the strength of the existing plow. It was then that an American mechanic named John Deere invented the all-steel one-piece share and moldboard. Soon afterward, the three-wheel sulky plow rolled in and with the gasoline engine came the tractor-drawn plow.
In its simplest form the moldboard plow is made of the share, the broad blade that cuts through the soil, the moldboard that is used for turning the furrow slice, and the landside; a plate on the opposite side from the moldboard that absorbs the side thrust of the turning action.
There were also horse-drawn moldboard plows that are no longer used but had a single bottom; tractor-drawn plows have from 1 to 14 hydraulically lifted and controlled bottoms staggered in tandem. Listers and middle busters are double-moldboard plows that leave a furrow by throwing the dirt both ways.
Today, modern plows are commonly multiply reversible and mounted on a tractor with a three-point linkage. These often have two to seven moldboards while semi-mounted plows can have up to 18 moldboards. Their lifting is assisted by a wheel about halfway along their length. The tractor’s hydraulics are used to reverse and lift the implement to change the furrow depth, and width. Of course, the plowman still has to set the draughting linkage from the tractor; this way the plow retains a proper angle in the soil. The modern tractor has a feature that can control the angle and depth automatically. A fantastic addition or accessory to the rear plow a two or three moldboard plow can be mounted to the front of the tractor; that is it is equipped with front three-point linkage.
Plough also comes in specialized forms including the chisel plow that losses up the soil with little soil disruption. It loosens soil while leaving crop resides at the top. There is also the riding plow is another which is used for crops such as potatoes or scallions because it has two back-to-back moldboards cutting a deep furrow on each pass with high ridges either side. The future of plows is bright as people always make improvements and variations for different needs.