Why a Han Chinese plough needed two oxen while Europe's needed up to eight
Before the 18th century, a European farmer might hitch four, six or even eight draught animals to one plough. In Han China, two usually sufficed, and later just one. The difference came down to a curved iron blade, and it changed how much land, and how many people, a region could feed.
Farming began with digging sticks and hoes, which suited places like the Nile banks, where yearly floods renewed the soil. Once oxen were domesticated in Mesopotamia and the Indus Valley, perhaps as early as the 6th millennium BC, people could drag a pointed stick through the ground instead. This scratch plough, or ard, cut shallow furrows that worked well in light, sandy soil. A field ploughed around 2800 BCE has been found at Kalibangan in India. Because the ard left untouched strips between furrows, farmers ploughed across fields in both directions, producing the squarish plots known as Celtic fields.
Heavy northern soils needed something stronger. The turn plough adds a knife called a coulter to slice downward, a share to cut sideways, and a mould board that lifts the strip of sod and flips it over, burying weeds and leaving drainage ridges that shed snowmelt faster. China's Han Empire developed a heavy iron version in the 1st and 2nd centuries. Europe's early mould boards were straight wooden boards, so clumsy that big teams were needed and large areas had to stay as pasture to feed the animals. Chinese farmers could shrink fallows, plough more ground and support larger populations.
The plough even starred in early literature. A Sumerian poem from the 3rd millennium BC stages an argument between a hoe and a plough over which tool is better. The English word came via Old Norse and seems to have first meant the wheeled heavy plough of Roman-era northwestern Europe; Celtic peoples were the first to add wheels.
Power shifted from oxen to horses and mules, then to steam engines, then to tractors early in the 20th century. Today some regions plough less deeply, or not at all, because repeated turning damages soil and encourages erosion.
Source: Plough
