農業革命
Convertible husbandry, also known as alternate husbandry or up-and-down husbandry, is a method of farming whereby strips of arable farmland were temporarily converted into grass pasture, known as leys. These remained under grass for up to 10 years before being ploughed under again, while some eventually became permanent pasturage. It was a process used during the 16th century through the 19th century by "which a higher proportion of land was used to support increasing numbers of livestock in many parts of England." Its adoption was an important component of the British Agricultural Revolution.