land area units

At least in the industrialized world, today's land measures are strictly geometric: the units are defined by squaring units of length. Most of the world uses the hectare (though the Ninth CGPM discouraged the use of the hectare, preferring plain square meters) and the United States uses the acre.

For most of human history, however, land area has been the intense concern of peasant farmers rather than developers, and land units reflected a farmer's experience of the land. Several types of non-geometrical units recur worldwide:

Person-day measures of land

Units representing the amount of land that could be cultivated in 1 day by hand, that is, without horse, oxen, or mules. Such units are often specific to a particular type of agricultural land. For example, in France one ouvrèe is 20 square rods of vinyard.

Person-day measures are seldom applied to fields where grain is raised.

Examples are the daieswork, about 10 square rods, and the hommèe.

Plow-day measures of land

Units representing the amount of land that could be plowed in a day. The acre was originally such a unit.

Region Unit Size,
sq. m
Length Breadth
England acre   1 furlong  
Roman jugerum      
Italian giornata      
French journal      
German morgen      
Irish ardagh      

Farmstead measures of land

Units representing the amount of land that a farmer owning a yoke of oxen could keep in cultivation. Typically these units are about 7 acres. Examples are the English yard-land and the oxgang.

Feudal measures of land

These units reflect society's requirements and not the efficient use of the farmer’s tools and time; they take into account only the land's yield and not cultivation practices. Typically the smallest such unit is that amount of land just large enough to produce a surplus sufficient to support a knight in service to the king. An example is the English hide.

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