Environmental Engineering Reference
In-Depth Information
in the world food supply as corn acreage expanded at the expense of
other crops, and corn normally fed to chickens, cattle, and swine was
diverted to ethanol production.
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Another example is the massive use of artifi cial nitrogen and phos-
phorous fertilizers in agriculture, which has had the unintended effect of
producing a large and growing number of dead zones in shallow ocean
waters around the world that are increasing in size over time as the use
of fertilizers increases in developing countries.
A fourth calamity has been the deliberate introduction of the kudzu
vine from Japan in 1876 into the southeastern United States. It was used
in Asia for erosion control, to enrich soil, and it is high-quality forage
for livestock. Unfortunately the Japanese did not bring any of kudzu's
natural insect enemies along with the plant. Kudzu grows rapidly, up to
1 foot per day, and from 60 to 100 feet in one growing season. It has
displaced native plants and has taken over large swaths of land in the
southeastern United States that were formerly used for other purposes.
The vine now hangs in curtains along highways all over the South and
covers 7 million acres, smothering trees and shrubs in its march over the
landscape (fi gure 11.1). Kudzu is invasive as far north as Connecticut.
Figure 11.1
Kudzu plants covering a house (center of photo) and surroundings. (Photo courtesy Jack
Anthony, jjanthony.com/kudzu)
