<P> Early in the first millennium, improvements in technique and technology began to emerge . Monasteries spread throughout Europe and became important centers for the collection of knowledge related to agriculture and forestry . The manorial system, which existed under different names throughout Europe and Asia, allowed large landowners significant control over both their land and its laborers, in the form of peasants or serfs . There were exchanges with distant regions mediated through the Arab world . Arabs introduced summer irrigation to Europe . Population continued to increase along with land use . </P> <P> By 900 AD in Europe, developments in iron smelting allowed for increased production, leading to developments in the production of farm tools such as ploughs, hand tools and horse shoes . The plough was significantly improved, developing into the mouldboard plough, capable of turning over the heavy, wet soils of northern Europe . This led to the clearing of forests in that area and a significant increase in agricultural production, which in turn led to an increase in population . Farmers in Europe moved from a two field crop rotation to a three field crop rotation in which one field of three was left fallow every year . This resulted in increased productivity and nutrition, as the change in rotations led to different crops being planted, including legumes, such as peas, lentils and beans . Inventions such as improved horse harnesses and the whippletree also changed methods of cultivation . </P> <P> Watermills were initially developed by the Romans, but were improved throughout the Middle Ages, along with windmills, and were provided the power needed to grind grains into flour, cut wood and process flax and wool, and irrigate fields . </P> <P> Field crops included wheat, rye, barley and oats; they were used for bread and animal fodder . Peas, beans, and vetches became common from the 13th century onward as food and as a fodder crop for animals; it also had nitrogen - fixation fertilizing properties . Crop yields peaked in the 13th century, and stayed more or less steady until the 18th century . Though the limitations of medieval farming were once thought to have provided a ceiling for the population growth in the Middle Ages, recent studies have shown that the technology of medieval agriculture was always sufficient for the needs of the people under normal circumstances, and that it was only during exceptionally harsh times, such as the terrible weather of 1315--17, that the needs of the population could not be met . </P>

Economy of western europe in the middle ages