Post on 28-Dec-2015
The Impact of Genetically Engineered Crops on Farm Sustainability in the United States
Public Briefing
NAS Lecture Room
April 13, 2010
David E. Ervin (chair), Portland State UniversityYves Carrière, University of ArizonaWilliam J. Cox, Cornell UniversityJorge Fernandez-Cornejo, USDA-Economic Research ServiceRaymond A. Jussaume, Washington State UniversityMichele C. Marra, North Carolina State UniversityMicheal D.K. Owen, Iowa State UniversityPeter H. Raven*, Missouri Botanical GardenL. LaReesa Wolfenbarger, University of Nebraska, OmahaDavid Zilberman, University of California, Berkeley
*Members of the National Academy of Sciences
Study Committee Members
• Study the environmental, economic, and social impacts of genetically engineered (GE) crops on U.S. farms
• Identify gaps and future applications of genetic engineering technology
• Funded by the National Research Council
Purpose of the Study
• Retrospective examination (1996-today)
• Geographically restricted to the United States
• Effects on farms with and without GE-crop production
Genetic Engineering Technology
3 Types of Resistance
• Herbicide Resistance (HR)
– Most U.S. crops engineered with resistance to glyphosate
• Insect Resistance (IR)
– Types of soil bacterium (Bacillus thuringiensis) introduced into plant to target susceptible insects
• Virus Resistance
Genetically Engineering Crops
0
20
40
60
80
100
2000 2001 2002 2003 2004 2005 2006 2007 2008 2009
Year
Per
cent
GE
cro
ps
All GE Corn Varieties
All GE Cotton Varieties
All GE Soybean Varieties
Nationwide acreage of GE soybean, corn, and cotton as a percentage of all acreage of these crops
Source: USDA-NASS (2001, 2003, 2005, 2007, 2009b).
GE Crops Analyzed in the Report
• Soybeans– Herbicide resistance
• Corn– Herbicide resistance – Insect resistance
• Cotton– Herbicide resistance– Insect resistance
Environmental Effects
• Complementary adoption of HR crops and conservation tillage practices
– Improves soil retention
–Probable improvement in surface water quality
– Infrastructure needed to track water quality effects
Herbicide-Resistant CropsTrends in conservation tillage practices
Source: CTIC, 2009; USDA-ERS, 2009.
0
20
40
60
80
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008
Year
Acr
es p
lant
ed (
mill
ion)
Conservation tillage: ≥30% residue Tillage leaving < 30% residue
No-till HR soybeans
Soybeans
0
5
10
15
20
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008
Year
Acr
es p
lant
ed (
mill
ion)
Conservation tillage: ≥30% residue Tillage leaving < 30% residue
No-till HR cotton
Cotton
0
20
40
60
80
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008
Year
Acr
es p
lant
ed (
mill
ion)
Conservation tillage: ≥30% residue Tillage leaving < 30% residue
No-till HR corn
Corn
0
20
40
60
80
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008
Year
Acr
es p
lant
ed (
mill
ion)
Conservation tillage: ≥30% residue Tillage leaving < 30% residue
No-till HR soybeans
Soybeans
0
20
40
60
80
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008
Year
Acr
es p
lant
ed (
mill
ion)
Conservation tillage: ≥30% residue Tillage leaving < 30% residue
No-till HR soybeans
Soybeans
0
5
10
15
20
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008
Year
Acr
es p
lant
ed (
mill
ion)
Conservation tillage: ≥30% residue Tillage leaving < 30% residue
No-till HR cotton
Cotton
0
5
10
15
20
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008
Year
Acr
es p
lant
ed (
mill
ion)
Conservation tillage: ≥30% residue Tillage leaving < 30% residue
No-till HR cotton
Cotton
0
20
40
60
80
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008
Year
Acr
es p
lant
ed (
mill
ion)
Conservation tillage: ≥30% residue Tillage leaving < 30% residue
No-till HR corn
Corn
0
20
40
60
80
1990 1992 1994 1996 1998 2000 2002 2004 2006 2008
Year
Acr
es p
lant
ed (
mill
ion)
Conservation tillage: ≥30% residue Tillage leaving < 30% residue
No-till HR corn
Corn
Environmental Effects
Glyphosate-Resistant Crops
• Substituted for more toxic herbicides
• Exclusive, repeated use reduced effectiveness of glyphosate for control of some weeds
• Expect further increases in weeds resistant to glyphosate if current practices continue
• Managing resistant weeds: a return to environmentally-harmful practices
• Development and implementation of efficient resistance management strategies needed if herbicide resistant crops are to remain an effective weed-management tool
Environmental Effects
Insect-Resistant Crops• If replacing broad-spectrum insecticides, then
favorable effects for beneficial insects may occur• No resistance of economic or agronomic
consequence so far
• Greater use of IR crops with multiple toxins targeting pest should delay the evolution of resistance further
Gene Flow
• No or very limited spatial overlap between GE crops and potentially interbreeding relatives in the United States
• Future concerns depend on what GE crops emerge in market
• Primarily a concern to producers of non-GE varieties of these crops
Environmental Effects
Adequate research has not been conducted on the social effects on GE crops
• Social impacts accompany technological developments
Social Effects
• Social relationships affect technology development
• Structure of seed industry affects farmers’ options
Social Effects
40
45
50
55
60
65
70
75
2000 2001 2002 2003 2004 2005 2006 2007 2008
Year
CR
4 (p
erce
nt)
Corn
Soybean
Share of planted acres on corn and soybean
seeds by largest four firms (CR4)
Source: Stiegert et al. (2009)
Areas in Need of Research
Social Effects
• Non-Adopters- Livestock Producers- Organic Farmers
• Property Rights and Ethical Issues
• Farmer Conflict and Community Stability
Adopters have benefitted from:• Cost-effective weed control• Reduced losses from insect pests• Reduced expenditures on pesticides and fuel• Increased worker safety• Greater flexibility in
farm management• Lower risk of yield variability
Economic Effects
Economic effects on non-GE producers are mixed and poorly understood
• Purchasing decisions of GE producers affect non-GE producers
• No quantitative estimate of economic impact on livestock producers
• Landscape-level effects on pests
• Costs of inadvertent gene flow
• Benefits of segregated markets
Economic Effects
• Stakeholder group needed to document emerging weed-resistance problems and develop cost-effect practices to increase longevity of HR technology
• Infrastructure needed on the water quality effects of GE crops
• Public and private research institutions improve monitoring and assessment capacity to ensure GE technologies contribute to sustainable agriculture
• Increased support for the development of ‘public goods’ traits through collaborative approaches to genetic engineering technology
Recommendations