Environmental Engineering Reference
In-Depth Information
than 30 Mha, was three orders of magnitude higher: the great nineteen-century
expansion began i rst with the settling of Ontario (Reaman 1970) and then with
the conversion of Canadian prairies to large rectangular crop i elds (Spector 1983).
This wave proceeded westward from Manitoba (it became a province in 1870)
through Saskatchewan to Alberta (both gaining provincial status only in 1905), and
it continued during the early twentieth century
Australian, and also Argentinian, contributions were comparatively much smaller.
As there was no cultivated land in mid-eighteenth century Australia (James Cook's
landing at Botany Bay took place in 1770, and substantial numbers of British set-
tlers began to arrive only during the 1840s and 1840s), it is impossible to offer a
comparative multiplier. By 1900 Australia's farmland had reached about 4.5 Mha,
more than 30 times the 1850 total. Argentina's farmland expanded about 18-fold
during the nineteenth century (to about 3.5 Mha), unlike Brazil's cultivated land,
which grew “only” sixfold (its great twentieth-century extension is described in
the next chapter). Globally, the 1750-1900 increase of cultivated land was more
than twofold, from about 360 to 850 Mha, with American and Asian grasslands
representing the largest category of natural ecosystems converted to cropland. At
the same time, that period also set new records for loss of arable land because of
an unprecedented rate of urban expansion and spreading industrialization.
During the twentieth century, arable land was added in all the countries that had
undergone rapid nineteenth-century expansion: by the year 2000 Australia's total
had grown more than 10-fold (by about 43 Mha) and Argentinian farmland had
nearly sextupled (gaining about 22 Mha), while Canada added about 75% (also
about 22 Mha) and Russia about 45% (130 Mha by 2000). In all these cases most
of the new farmland was planted to grains, above all to wheat. The most ambitious
program to expand wheat production was the Soviet cultivation of virgin lands
(
tselinny
, east of the lower Volga and extending to western Siberia), pushed by
N. S. Khrushchev to solve the country's chronic agricultural underperformance
(Durgin 1962). Between 1953 and 1964 more than 42 Mha were plowed, more
than 70% of it in northeastern Kazakhstan (
Tselinnyi krai
), and more than 70% of
the added land was devoted to overcoming the chronic dei cits in the Soviet grain
production—but in the end, the program did not meet its goals, and the USSR had
to turn to large-scale imports of U.S. grain during the 1970s (Gustafson 1979).
The U.S. farmland expanded by more than 40% during the i rst half of the
twentieth century (adding about 67 Mha) before higher yields and the abandonment
of cultivation in the eastern United States stopped any further growth. Signii cant
areas of arable land were also added in the world's two most populous countries.
