Annotated
Bibliography Entry
Reference:
CAST 2002
Title: Comparative Environmental Impacts of Biotechnology-derived and
Traditional Soybean, Corn, and Cotton Crops
Authors:
Carpenter, J., Felsot, A., Goode, T., Hammig, M., Onstad, D., Sankula, S.
Publisher: Council for Agricultural Science and Technology (CAST), Ames,
Iowa
Publication details: June
2002, 189p. Sponsored
by the United Soybean Board.
Executive
Summary
Nine
potential environmental impacts
General
Conclusions
Biotechnology-derived
soybean
Biotechnology-derived
corn (maize)
Biotechnology-derived
cotton
Authors'
Recommendations
Table of Contents
Authors
Back
to USA page
Executive
Summary
A
comprehensive review of the scientific literature supports the conclusion that
overall the currently commercialized biotechnology-derived
soybean, corn, and
cotton crops yield environmental benefits. Furthermore, a critical analysis of
the literature supports the idea that biotechnology-derived soybean, corn, and
cotton pose no environmental concerns unique to or different from those
historically associated with conventionally developed crop varieties.
Soybean,
corn, and cotton farmers in industrial and developing nations have rapidly
adopted biotechnology-derived commodity crops during the six years of their
commercial availability. In 2001, farmers planted biotechnology-derived seed
on 46% of global soybean acres, 7% of global corn acres, and 20% of global
cotton acres. To date, nearly all of the planted biotechnology-derived crops
have introduced tolerance to selected herbicides for weed control or have
introduced protection against pest insects. Of the 129.9 million acres (52.6
million hectares) of biotechnology-derived crops planted in 2001,
seventy-seven percent were tolerant of specific herbicides (herbicide
tolerant), fifteen percent were resistant to selected insect damage (insect
resistant), and eight percent were both herbicide tolerant and insect
resistant.
The
peer-reviewed literature, regulatory assessments, nongovernmental
organizations and the popular media have repeatedly raised questions about the
environmental safety of biotechnology-derived crops. To answer these questions
relative to soybean, corn, and cotton, the scientific literature was reviewed
and analyzed to evaluate the environmental impacts of commercially available
biotechnology-derived crops in relation to the current agricultural practices
for crop and pest management in conventionally bred crops.
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Nine
potential environmental impacts were identified as follows:
1.
Changes in pesticide use patterns - Does the adoption of biotechnology-derived soybean, corn, and cotton
impact the use of pesticides and, if so, do these changes alter farmer
practices in ways that affect water quality or soil health?
2.
Soil management and conservation tillage -
Does adoption of biotechnology-derived soybean, corn, and cotton lead to
changes in the adoption of no-till and other conservation tillage practices or
otherwise impact soil erosion, moisture retention, soil nutrient content,
water quality, fossil fuel use, and greenhouse gasses?
3.
Crop weediness -
Have biotechnology-derived soybean, corn, and cotton acquired weediness
traits?
4.
Gene flow and outcrossing - Do biotechnology-derived soybean, corn, and cotton hybridize with
local plants or crops and impact the genetic diversity in the areas where the
biotechnology-derived soybean, corn, and cotton are planted?
5.
Pest resistance -
Do biotechnology-derived soybean, corn, and cotton possess plant-protectant
traits to which pests will become resistant and, if so, is the development of
resistance to these traits different than development of resistance to
conventional chemical and microbial pesticides? How is the development of
resistance being managed?
6.
Pest population shifts - Do biotechnology-derived soybean, corn, and cotton cause changes in
weed or secondary insect pest populations that impact the agricultural system
or ecology of the surrounding environment?
7.
Nontarget and beneficial organisms
Do biotechnology-derived soybean, corn, and cotton with pest protection
characteristics have an impact on natural enemies of pests (i.e., predators
and parasitoids) or on other organisms in the soil and crop canopy?
8.
Land use efficiency/productivity - Does the adoption of biotechnology-derived soybean, corn, and cotton
impact crop yields or impact the need for cultivating forested or marginal
land?
9.
Human exposure -
Do the traits of herbicide tolerance and resistance to pest insects in
biotechnology-derived soybean, corn, or cotton pose any new or different
safety concerns in comparison to conventionally bred crops with similar
traits?
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General conclusions
Biotechnology-derived
crops provide options and potential solutions for a number of challenges in
modern agriculture, but the extent to which they may be viable or the
preferred option is dependent on many economic, social, and regional factors.
Nevertheless, a number of general conclusions about biotechnology-derived
soybean, corn, and cotton are supported by the literature.
Biotechnology-derived soybean, corn, and cotton provide insect, weed, and
disease management options that are consistent with improved environmental
stewardship in developed and developing nations.
Biotechnology-derived crops can provide solutions to environmental and
economic problems associated with conventional crops including production
security (consistent yields), safety (worker, public, and wildlife), and
environmental benefits (soil, water, and
ecosystems).
Although not the only solution for all farming situations, the first
commercially available biotechnology-derived crops, planted on over 100
million acres (40.5 million hectares) worldwide, provide benefits through
enhanced conservation of soil and water and beneficial insect populations and
through improved water and air quality.
The high adoption rates for commercially available biotechnology-derived crops
can be attributed to economic benefits for farmers.
When biotechnology-derived crops are available to small farmers in developing
nations, the farmers can realize environmental benefits and reduce worker
exposure to pesticides.
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Biotechnology-derived
soybean
Herbicide-tolerant soybean is the most widely adopted biotechnology-derived
crop, planted on 68% of United States soybean acreage and over 98% of
Argentinas soybean acreage in 2001. The United States and Argentina
together account for 99% of total herbicide-tolerant soybean production in the
world, which represents 46% of the total acreage of soybean planted. Farmers
in the United States are projected to plant 74% of soybean acreage to
herbicide-tolerant soybean in 2002.
The major reasons farmers have adopted the herbicide-tolerant soybean so
widely are lowered production costs, reduced crop injury, and simplicity and
flexibility in weed management.
Biotechnology-derived herbicide-tolerant soybean has facilitated the adoption
of conservation tillage. No-till soybean acreage in the United States has
increased by 35% since the introduction of herbicide-tolerant soybean. Similar
increases are observed in Argentina, which can be attributed in part to
reliable and effective weed control provided by herbicide-tolerant soybean.
Use of no-till farming in soybean production results in decreased soil
erosion, dust, and pesticide run-off and in increased soil moisture retention
and improved air and water quality.
Biotechnology-derived soybean may lead to increased yield, through improved
weed control or the ability to adopt narrow-row spacing, resulting in more
efficient land use.
Cost savings in biotechnology-derived herbicide-tolerant soybean programs have
allowed adopters to decrease weed control costs, leading to price cuts of
conventional herbicide programs. The result has been weed control cost savings
for both adopters and nonadopters.
Farmers using biotechnology-derived herbicide-tolerant soybean are able to use
a herbicide that rapidly dissipates to inactive amounts in soil, has little
potential for water contamination as a substitute for herbicides used with
conventional soybean varieties, and allows greater flexibility in timing of
application.
Biodiversity is maintained in biotechnology-derived herbicide-tolerant soybean
fields. Soil microbes, beneficial insects, and bird populations in
conservation tillage biotechnology-derived herbicide-tolerant and conventional
soybean fields were similar in number and variety.
Both conventional and biotechnology-derived soybean production systems require
effective management strategies for weed population shifts and to prevent the
development of weed resistance to herbicides. Emerging reports on glyphosate-resistant
weeds
may be a concern in herbicide-tolerant soybean; however, herbicide resistance
in weeds is not unique to biotechnology-derived crops.
Conclusions regarding yield decreases attributed to the biotechnology-derived
herbicide-tolerant trait may be inaccurate because the study design included
improper comparisons between the biotechnology-derived varieties and
conventional varieties.
Soybean with insect protection properties is also in development and will be
useful in climatic regions where insect pressures justify insecticide
applications.
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Biotechnology-derived
corn (maize)
Bt corn can enhance the biodiversity of cornfields because beneficial
insects fare better than when conventional cornfields are sprayed with
insecticides. Moreover, field studies of biotechnology-derived corn show that
populations of beneficial insects are not adversely affected.
Use of Bt corn can decrease farm worker exposure to certified organic Bt
sprays and chemical insecticides.
Decrease of naturally occurring mold toxins resulting from use of Bt corn
can provide direct benefits to people and corn-fed livestock. Insect-protected
corn is less vulnerable to mold infestation.
Yields since the introduction of insect-protected and herbicide-tolerant corn
have continued at historically high levels. When European corn borer pressure
is high, farmers obtain significant economic benefit from the use of
insect-protected corn.
Herbicide-tolerant corn varieties allow use of herbicides that are less
persistent in the environment and reduce the risks of herbicide run-off into
surface water. These herbicide-tolerant corn varieties allow for greater
flexibility in the timing of application and encourage the application of
reduced and no-till soil and soil moisture management practices.
Insect Resistance Management (IRM) plans have been required, developed, and
implemented to prevent or to delay the development of insect resistance to Bt.
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Biotechnology-derived
cotton
Herbicide-tolerant cotton enhances the use of herbicides that are less
persistent in the environment.
Herbicide-tolerant cotton is a major factor in promoting reduced and no-till
farming practices, which result in improved soil and soil moisture management
and reduced energy use.
Herbicide-tolerant cotton provides greater flexibility for the timing of
herbicide applications for effective weed control and less damage to the
cotton plants.
Use of biotechnology-derived cotton in developing nations does not require
significant capital investment, changes in cultural practices, or significant
training for adoption.
Rapid adoption of Bt cotton in China serves as an example of how, in
developing nations, plant-incorporated protectants greatly decrease the volume
of pesticides applied and the risks of pesticide run-off while increasing
safety and health of agricultural workers.
Bt cotton has been documented to have a positive effect on the number
and diversity of beneficial insects in cotton fields in the United States and
Australia.
The introduction of Bt cotton in Australia, India, and the United
States demonstrates the ability of these varieties to alleviate problems with
insect resistance to chemical pesticides. The future production of cotton in
these regions was in jeopardy prior to the introduction of Bt cotton.
The ability to add several different genes to control the same pest should
delay the time it takes for pesticide resistance to develop.
Bt and herbicide-tolerant cotton decreases production costs to farmers
and increases the range of options available for whole-farm management
systems.
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Authors
Recommendations
1.
Given that biotechnology-derived crops can provide positive net
environmental benefits, we recommend continued development of agricultural
biotechnology to enhance environmental stewardship.
2.
Biotechnology provides a tool for management of production risk in
agriculture. We recommend evaluating the role of biotechnology-derived crops
in the context of whole-farm management.
3.
When drawing conclusions regarding the impacts of biotechnology-derived
crops on productivity, we recommend that conclusions be based on comparisons
involving whole-farm systems.
4.
When comparing the consequences of a specific trait, we recommend the
following characteristics be held constant: varieties that are genetically
identical in all aspects other than the trait(s) being evaluated; the crops be
grown during the same time in the same geographic location; and use of
identical soil and crop management practices. For example, having observed
contradictory and inconsistent data regarding yields in some crops, we
recommend better measurement of yield impacts.
5.
We recommend evaluating the environmental impacts of
biotechnology-derived crops in agricultural regions where the crops may be
adopted and in the context of viable, currently available alternatives and
practices in agriculture.
6.
We recommend large-scale and farm-scale field studies to provide
supplemental information to document long-term environmental benefits and
safety impacts of adopting biotechnology-derived crops.
7.
We recommend continued development of policies for implementation of
effective management strategies for insect and weed resistance in both
conventional and biotechnology-derived crops. Also, we recommend continued
research on management strategies to abate or slow the development of
resistance to new and existing pest control tools.
8.
Recognizing that gene flow is a natural process that may increase
biodiversity, we recommend that research on gene flow between
biotechnology-derived and other crops or native plants focus on the
environmental and social impacts/consequences of that gene movement.
9.
Recognizing the potential for biotechnology-derived corn varieties to
help resolve current corn rootworm control problems stemming from the
development of insect resistance to both chemical insecticides and crops
rotation, we recommend research include consideration of resistance management
strategies as well as impacts on soil and other nontarget organisms.
10.
Recognizing that enhanced land use efficiency is an important
environmental benefit, we recommend continued development of
biotechnology-derived hybrids that improve crop yields.
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CAST
2002. Comparative Environmental Impacts of Biotechnology-derived and
Traditional Soybean, Corn, and Cotton Crops. Carpenter, J., Felsot,
A., Goode, T., Hammig, M., Onstad, D., Sankula, S.
Table
of Contents
Tables
and Figures List v
Foreword
vii
I.
Executive Summary 1
II.
Introduction 5
III.
Overview of Modern Biotechnology 7
IV.
Soybean 15
V.
Corn 51
VI.
Cotton 101
VII.
Literature Cited 135
Appendix
I. Glossary 179
Appendix
II. Abbreviations, Acronyms, and Symbols 185
Appendix
III. List of Reviewers 189
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Authors
Janet
Carpenter, M.S.
The National Center for Food and Agricultural Policy
1616 P Street, N.W.
Washington, DC 20036
Allan
Felsot, Ph.D.
Washington State University
Entomology/Environmental Toxicology
2710 University Drive
Richland, WA 99352
Timothy
Goode
Clemson University
Department of Agricultural and Applied Economics
229 Barre Hall
Clemson, SC 29634
Michael
Hammig, Ph.D.
Clemson University
Department of Agricultural and Applied Economics
229 Barre Hall
Clemson, SC 29634
David
Onstad, Ph.D.
University of Illinois
Department of Natural Resources and Environmental Sciences
1201 S. Dorner Dr
Urbana, IL 61801
Sujatha
Sankula, Ph.D.
The National Center for Food and Agricultural Policy
1616 P Street, N.W.
Washington, DC 20036
Project
Coordination
Cindy
Lynn Richard, CIH
Program Coordinator
Council for Agricultural Science and Technology (CAST)
505 Capitol Court, N.E., Suite 200
Washington, DC 20002
Phone: (202) 675-8333, ext. 12
Linda
M. Chimenti, MLS
Managing Scientific Editor
Council for Agricultural Science and Technology (CAST)
4420 West Lincoln Way
Ames, Iowa 50014
Phone: (515) 292-2125, ext. 31
Web site: http://www.cast-science.org
and http://www.unitedsoybean.org
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FootnoteBiotechnology-derived
refers to the use of molecular biology and/or recombinant DNA technology, or in
vitro gene transfer, to develop products or impart specific capabilities in
plants or other living organisms.
New Genetics, Food &
Agriculture: Scientific Discoveries - Societal Dilemmas