The Impact of Genetically Engineered Crops on Farm Sustainability in the United States (2010) / Chapter Skim
Currently Skimming:
Summary
Summary
Pages 1-18
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 1... ...
traits allow plants either to produce their own insecticide, so that the yield lost to insect feeding is reduced, or to resist herbicides, so that herbicides can be used to kill a broad spectrum of weeds without harming crops. Those traits have been incorporated into most varieties of soybean, corn, and cotton grown in the United States.
|
From page 2... ...
To capture the broad array of potential effects, the committee interpreted "farm level" as applying both to farmers who do not produce GE crops and those who do because genetic engineering is a technology of extensive scope, and its influences on farming practices have affected both types of farmers. Therefore, to the extent that peerreviewed literature is available, the report draws conclusions about the environmental, economic, and social effects, both favorable and unfavorable, associated with the use of GE crops for all farmers in the United States over the last 14 years.
|
From page 3... ...
The social effects of agricultural biotechnology have largely been unexplored, in part because of an absence of support for research on them. Environmental Effects Generally, GE crops have had fewer adverse effects on the environment than non-GE crops produced conventionally.
|
From page 4... ...
Furthermore, communities of weeds less susceptible to glyphosate are 1.4 100 1.2 80 Pounds of ac tiv e ingredient per Perc ent of soybean acres 1 planted ac re 60 0.8 0.6 40 0.4 20 0.2 0 0 1996 1998 2000 2002 2004 2006 2008 Year Gly phos ate Other herbic ides Perc ent ac res HR FIGURE S-1 Application of herbicide to soybean and percentage of acres of herbicide-resistant soybean. NOTE: The strong correlation between the rising percentage of HR soybean acres planted over time, the increased applications of glyphosate, and the decreased use of other herbicides suggests but does not confirm causation between these variables.
|
From page 5... ...
Tilled soil forms a crust, which reduces the ability of water to infiltrate the surface and leads to runoff that can pollute surface water with sediments and chemicals. Conservation tillage, which leaves at least 30 percent of the previous crop's residue on the field, improves soil quality and water infiltration and reduces erosion because more organic matter is left on the soil surface, thereby decreasing disruption of the soil.
|
From page 6... ...
Finding 3. Targeting specific plant insect pests with Bt corn and cotton has been successful, and the ability to target specific plant pests in corn and cotton continues to expand.
|
From page 7... ...
0.3 100 Pounds of active ingredient 0.25 80 Percent of corn acres per planted acre 0.2 60 0.15 40 0.1 20 0.05 0 0 1996 1998 2000 2002 2004 2006 2008 Year Pounds of active ingredient Perc ent ac res Bt c orn FIGURE S-4 Pounds of active ingredient of insecticide applied per planted acre and percent acres of Bt corn, respectively. NOTE: The strong correlation between the rising percentage of Bt corn acres planted over time and the decrease in pounds of active ingredient per planted acre suggests but does not confirm causation between these variables.
|
From page 8... ...
For the three major GE crops, gene flow to wild or weedy relatives has not been a concern to date because compatible relatives of corn and soybean do not exist in the United States and are only local for cotton. For other GE crops, the situation varies according to species.
|
From page 9... ...
Many farmers have benefited economically from the adoption of Bt crops by using lower amounts of or less expensive insecticide applications, particularly where insect pest populations were high and difficult to treat before the advent of Bt crops. The incomes of those who have adopted genetic-engineering technology have benefited from some combination of yield protection and lower costs of production.
|
From page 10... ...
GE seed is typically more expensive than conventional seed, and the net return in terms of higher yields and lower costs of production for a farmer considering adoption does not always offset the technology fee. However, studies have found that high rates of adoption of GE crops can be attributed in part to the value that farmers place on increased worker safety, perceived greater simplicity and flexibility in farm management (including more off-farm work opportunities)
|
From page 11... ...
Feed costs are nearly half the variable costs for livestock producers, so even moderate price fluctuations can affect their net incomes substantially. Livestock producers also benefit from increased feed safety due to reduced levels of mycotoxins in the grain.
|
From page 12... ...
Similarly, if GE traits cross into weedy relatives, weed-control expenses will be higher for all fields on to which the weeds spread, whether a farmer grows GE crops or not. In addition, gene flow of GE traits into organic crops could jeopardize crop value by rendering outputs unsuitable for high-value foreign or other markets that limit or do not permit GE material in food products; the extent of that effect has not been documented during the last 5 years.
|
From page 13... ...
Large seed companies have not commercialized GE traits in many other crops because their market size has been insufficient to cover necessary research and development costs or because of concerns related to consumer acceptance and gene flow. Public research institutions continue to enhance the genetics of other crops, but full access to state-of-the-art technology (like genetic engineering)
|
From page 14... ...
Conclusion 2. Given that agriculture is the largest source of surface water pollution, improvements in water quality resulting from the complementary nature of herbicide-resistance technology and conservation tillage may represent the largest single environmental benefit of GE crops.
|
From page 15... ...
Commercialized GE traits are targeted at pest control, and when used properly, they have been effective at reducing pest prob lems with economic and environmental benefits to farmers. However, genetic engineering could be used in more crops, in novel ways beyond herbicide and insect resistance, and for a greater diversity of purposes.
|
From page 16... ...
2006. Environmental effects of genetically modified crops: Dif ferentiated risk assessment and management.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.