The carruca or caruca was a kind of heavy plow important to medieval agriculture in Northern Europe. The carruca used a heavy iron plowshare to turn heavy soil and may have required a team of eight oxen. The carruca also bore a coulter and moldboard. It gave its name to the English carucate.
The heavy iron moldboard plow was developed in China's Han Empire in the 1st and 2nd century. Based on linguistic evidence, the carruca may have been employed by some Slavs by AD 568. It was present in Italy's Po Valley by 643 and—judging from the terminology in the Lex Alemannorum—in southwestern Germany by 720. The carruca was introduced to the British Isles by the Norse in the late 9th century.
The scratch plow which preceded it and continued in use in the Byzantine Empire had been developed for the light sandy soils of Southern Europe. The carrucate was able to turn over a furrow and provided greater drainage in Northern Europe's heavy soils, an important technological advancement for the medieval agricultural economy. Its use required coöperation among peasants because few would own enough oxen to pull it. The scratch plough tended to create square fields because the field was ploughed twice, the second time at right angles to the first. By contrast, the carruca was most efficient in oblong paddocks. Because this pattern conflicted with traditional ownership arrangements, the carruca was probably most often used when breaking uncultivated ground.
- White Jr., Lynn, The Life of the Silent Majority, pg. 88 of Life and Thought in the Early Middle Ages, ed. Robert S. Hoyt, University of Minnesota Press, Minneapolis. 1967
- Western Civilization Sixth Edition by Jackson J. Spielvogel
- Fontana Economic History of Europe - The Middle Ages, ed C Cipolla, article by L White