Botkin Environmental Science Earth as Living Planet 8th txtbk

11.3 What We Grow on the Land 219
North
America
Europe
A s i a
North
Pacific
Ocean
North
Atlantic
Ocean
North
Pacific
Ocean
Africa
Wheat
Corn (maize)
Rice
South
America
South
Atlantic
Ocean
Indian Ocean
Australia
South
Pacific
Ocean
FIGURE 11.9 Geographic distribution of world production of a few major small-grain crops.
2,500,000,000
World small-grain production
2,000,000,000
Metric tons
1,500,000,000
1,000,000,000
500,000,000
0
1983 1989 1992 1996 2000
Year
Production
FIGURE 11.10 World small-grain
production since 1983. (Source: FAO
statistics FAOSTATS Web site.)
pasture worldwide—an area larger than the combined sizes
of Canada, the United States, Mexico, Brazil, Argentina,
and Chile. 2
Almost half of Earth’s land area is used as rangeland,
and about 30% of Earth’s land is arid rangeland, land
easily damaged by grazing, especially during drought.
Much of the world’s rangeland is in poor condition from
overgrazing. In the United States, where more than 99%
of rangeland is west of the Mississippi River, rangeland
conditions have improved since the 1930s, especially in
upland areas. However, land near streams and the streams
themselves continue to be heavily affected by grazing.
Grazing cattle trample stream banks and release
their waste into stream water. Therefore, maintaining a
high-quality stream environment requires that cattle be
fenced behind a buffer zone. The upper Missouri River
is famous for its beautiful “white cliffs,” but private lands
along the river that are used to graze cattle take away
from the scenic splendor. The large numbers of cattle
that come down to the Missouri River to drink damage