Environmental Engineering Reference
In-Depth Information
buffaloes, camels, horses, sheep, and goats in the Old World but was limited to
llamas, alpacas, and guinea pigs in South America. The most common domesticated
birds were fowls of Southeast Asian origin, ducks, geese, and pigeons throughout
the Old World; turkeys were the only birds domesticated in America.
Grains—primarily wheat, rice, barley, rye, and oats in Eurasia, millets in Africa,
and corn in the Americas—eventually became the most important staples, and
legumes (beans, peas, lentils, and soybeans in the Old World, beans in the Americas)
supplied most of the dietary protein. Tubers—mainly sweet potatoes, taro, and
cassava—were the staples in tropical societies, though after 1600 Andean potatoes
diffused worldwide to become a major source of carbohydrates. These staples were
supplemented by a wide variety of vegetables and fruits and in most societies also
by the cultivation of oilseeds (two leguminous species, soybeans and peanuts, as
well as sunl ower, rapeseed, sesame, and olive).
Low-yield cropping remained the norm even in the economically most advanced
regions until the modern era: in much of Atlantic Europe until the eighteenth
century, on the Great Plains of North America until the late nineteenth century.
Gradual intensii cation of inputs aimed at securing higher and more stable yields
relied on leveling and terracing i elds, building often elaborate irrigation systems,
and recycling organic matter, but it resulted in only slowly rising yields rather than
in fundamental productivity breakthroughs, and higher outputs had to be secured
primarily by expanding the cultivated land.
In China this process entailed centuries of cropland expansion both in the arid
northern regions and in the rainy south suited for rice cultivation, where it had to
be usually preceded by deforestation; in Europe, cropland expansion led to the
gradual colonization of less productive land and large-scale deforestation, i rst in
the Mediterranean and later in Atlantic, Central, and Eastern Europe. In North
America it led i rst to extensive deforestation in New England and in the mid-
Atlantic states and later (after 1850) to a rapid conversion of the continent's interior
grasslands to crop i elds; a similar process took place in Ukraine and parts of Euro-
pean Russia, southern Siberia, and Kazakhstan.
Modii cation of this extensive farming began i rst by the introduction of more
intensive practices in the most densely settled parts of Eurasia, but low-yield agri-
culture dominated the Americas even during the nineteenth century. Land claims of
extensive cropping can be easily appraised by reviewing the best evidence of crop
yields in ancient societies and in their medieval successors. Because of the Nile's
minuscule gradient (1:12,000), there was no perennial canal irrigation in ancient
dynastic Egypt, just levees, drainage channels, and storage basins used to manage
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