Ithaca, New York
October 21, 2004
In a world plagued by shortages
of water, three facts stand out in an analysis by Cornell
University ecologists: Less than 1 percent of water on the
planet is fresh water; agriculture in the United States consumes
80 percent of the available fresh water each year; and 60
percent of U.S. water intended for crop irrigation never reaches
the crops.
Their report in the October
2004 journal BioScience (Vol. 54, No. 10, "Water
Resources: Agricultural and Environmental Issues") names farmers
as "the prime target for incentives to conserve water." The
report is particularly critical of irrigation practices in the
United States, where subsidized "cheap water" offers scant
incentive for conservation.
Thirsty
Agriculture
Estimated liters
of water required to produce 1 kilogram of food
|
|
Crop
Rice
Wheat
Potatoes (dry
weight)
Broiler chicken
Beef
|
Liters/kg
1,600
900
630
3,500
43,000
|
|
(Source: "Water Resources: Agricultural and
Environmental Issues," BioScience,
October 2004) |
|
"Part of the problem is the
decision by farmers on what to grow where," says David Pimentel,
a Cornell professor who led nine student ecologists through an
exhaustive analysis of research conducted at other institutions
and government agencies. "We learned, for example, that to
produce wheat using irrigation requires three times more fossil
energy than producing the same quantity of rain-fed wheat. The
next time you make a sandwich, think about this: One pound of
bread requires 250 gallons of water to produce the grains that
go into the bread."
At particular risk, the
ecologists discovered, are aquifers, the once-vast but now
diminishing underground repositories of water that are tapped by
wells for agricultural irrigation and drinking water. "Given
that many aquifers are being over-drafted, government efforts
are needed to limit the pumping to sustainable withdrawal levels
. . . Integrated water resource management programs offer many
opportunities to conserve water resources for everyone, farmers
and the public," they write in their report in BioScience,
a publication of the American Institute of Biological Sciences.
Their report concludes with a
six-point priority list for using water wisely:
- Farmers should be the
prime target for incentives to conserve water.
- Water-conserving
irrigation practices, like drip irrigation, should be
implemented to reduce water waste.
- Water- and
soil-conservation practices, like cover crops and crop
rotations, should be implemented to minimize rapid water
runoff related to soil erosion.
- Water subsidies that
encourage the wasteful use of water by farmers and others
should be eliminated.
- Forests, wetlands and
natural resources should be protected to enhance the
conservation of water.
- Water pollution needs to
be controlled to protect public health, agriculture and the
environment.
Other authors of theBioScience<
report were students in Pimentel's graduate-level class,
Environmental Policy: Bonnie Berger, David Filiberto, Michelle
Newton, Benjamin Wolfe, Elizabeth Karabinakis, Steven Clark,
Elaine Poon, Elizabeth Abbett and Sudha Nandagopal.
Related World Wide Web site:
BioScience journal:
http://www.aibs.org/bioscience/current_issue.html
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