Task: Question Answering
Input (English): Passage: The Scottish economy of this period was dominated by agriculture and by short-distance, local trade. There was an increasing amount of foreign trade in the period, as well as exchange gained by means of military plunder. By the end of this period, coins were replacing barter goods, but for most of this period most exchange was done without the use of metal currency.Most of Scotland's agricultural wealth in this period came from pastoralism, rather than arable farming. Arable farming grew significantly in the "Norman period", but with geographical differences, low-lying areas being subject to more arable farming than high-lying areas such as the Highlands, Galloway and the Southern Uplands. Galloway, in the words of G. W. S. Barrow, "already famous for its cattle, was so overwhelmingly pastoral, that there is little evidence in that region of land under any permanent cultivation, save along the Solway coast". The average amount of land used by a husbandman in Scotland might have been around 26 acres. The native Scots favoured pastoralism, in that Gaelic lords were happier to give away more land to French and Middle English-speaking settlers, while holding on tenaciously to upland regions, perhaps contributing to the Highland/Galloway-Lowland division that emerged in Scotland in the later Middle Ages. The main unit of land measurement in Scotland was the davoch (i.e. "vat"), called the arachor in Lennox and also known as the "Scottish ploughgate". In English-speaking Lothian, it was simply ploughgate. It may have measured about 104 acres (0.42 km2), divided into 4 raths. Cattle, pigs and cheeses were among the chief foodstuffs, from a wide range of produce including sheep, fish, rye, barley, bee wax and honey.
David I established the first chartered burghs in Scotland, copying the burgher charters and Leges Burgorum (rules governing virtually every aspect of life and work) almost verbatim from the English customs of Newcastle-Upon-Tyne. Early burgesses were usually Flemish, English, French and German, rather than Gaelic Scots. The burgh's vocabulary was composed totally of either Germanic and French terms. The councils that ran individual burghs were individually known as lie doussane, meaning the dozen. 
Question: What is the main unit of land measurement in the country where pastoralism was the main source of agricultural wealth?
Output (English): davoch.