From the April 16 Science, Biotech Crops Good for Farmers and Environment (subscription required):
Fourteen years after genetically engineered crops began to take off in the United States, the overall benefits to farmers are clear, according to a new report from the National Research Council (NRC) of the National Academies. The shift from conventionally grown crops has paid off economically and environmentally, says the panel. “We can stop arguing about whether the environmental and economic impacts are significant,” says agricultural economist Nicholas Kalaitzandonakes of the University of Missouri, Columbia, who was not on the panel…
Reduced tillage could offer the “largest single environmental benefit of GE crops,” the panel found, because it should mean less sediment, fertilizer, and pesticides washing into streams. But this hasn’t been proven, so the panel recommends that the U.S. Geological Survey investigate the impact of reduced tillage on water quality.
Key findings from Impact of Genetically Engineered Crops on Farm Sustainability in the United States, produced by National Research Council of the National Academy of Sciences (order reflect report structure rather than importance):
• When adopting GE [genetically engineered] herbicide-resistant (HR) crops, farmers mainly substituted the herbicide glyphosate for more toxic herbicides. However, the predominant reliance on glyphosate is now reducing the effectiveness of this weed-management tool.
• The adoption of HR crops complements conservation tillage practices, which reduces the adverse effects of tillage on soil and water quality.
• 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. Insecticide use has decreased with the adoption of insect-resistant (IR) crops. The emergence of insect resistance to Bt crops has been low so far and of little economic or agronomic consequence; two pest species have evolved resistance to Bt crops in the United States.
• 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. However, gene flow to non-GE crops has been a concern for farmers whose markets depend on an absence of GE traits in their products. The potential risks presented by gene flows may increase as GE traits are introduced into more crops.
• Farmers who have GE crops have experienced lower costs of production and obtained higher yields in many cases because of more cost-effective weed control and reduced losses from insect pests. 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.
• Adapters of GE crops experienced increased worker safety and greater simplicity and flexibility in farm management, benefitting farmers even though the cost of GE seed is higher than non-GE seed. Newer varieties of GE crops with multiple GE traits appear to reduce production risk for adopters.
• The effect GE crops have had on prices received by farmers for soybeans, corn, and cotton is not completely understood.
• To the extent that economic effects of GE-crop plantings on non-GE producers are understood, the results are mixed. By and large, these effects have not received adequate research. [Eg, food safety increased in livestock feed, downward pressure on price, lower pest control costs due to reduced pest populations, cost of new insecticides whether or not non-GE farming practices led to the need]
• Research on the dissemination of earlier technological development in agriculture suggests that favorable and unfavorable social impacts exist from the dissemination of genetic-engineering technology. However, these impacts have not been identified or analyzed. [eg, the impact on farmers with less access to credit, fewer social connections to university and private-sector researchers who grow crops for smaller markets, labor dynamics, farm structure, community viability]
• The proprietary terms under which private-sector firms supply GE seeds to the market has not adversely affected the economic welfare of farmers who adopt GE crops. Nevertheless, ongoing research is needed to investigate how market structure may evolve and affect access to non-GE or single-trait seed. Furthermore, there has been little research on how increasing market concentration of seed suppliers affects overall yield benefits, crop genetic diversity, seed prices, and farmers’ planting decisions and options.
Conclusions and Recommendations
• Weed problems in fields of HR crops will become more common as weeds evolve resistance to glyphosate or weed communities less susceptible to glyphosate become established in areas treated exclusively with that herbicide. Though problems of evolved resistance and weed shifts are not unique to HR crops, their occurrence, which is documented, diminishes the effectiveness of a weed-control practice that has minimal environmental impacts. Weed resistance to glyphosate may cause farmers to return to tillage as a weed-management tool and to the use of potentially more toxic herbicides. A number of new genetically engineered HR cultivars are currently under development and may provide growers with other weed management options when fully commercialized. However, the sustainability of these new GE cultivars will also be a function of how the traits are managed. If they are managed in the same fashion as the current genetically engineered HR cultivars, the same problems of evolved herbicide resistance and weed shifts may occur. Therefore, farmers of HR crops should incorporate more diverse management practices, such as herbicide rotation, herbicide application sequences, and tank-mixes of more than one herbicide; herbicides with different modes of action, method of application, and persistence; cultural and mechanical control practices; and equipment-cleaning and harvest practice that minimize the dispersal of HR weeds.
• 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. However, the infrastructure to track and analyze these effects is not in place.
• The environmental, economic, and social effects on adopters and nonadopters of GE crops has changed over time, particularly because of changes in pest responses to GE crops, the consolidation of the seed industry, and the incorporation of GE traits into most varieties of corn, soybean, and cotton. However, empirical research into the environmental and economic effects of changing market conditions, and farmer practices have not kept pace. Furthermore, little work has been conducted regarding the effects on livestock producers and nonadopters and on the social impacts of GE crops. Issues in need of further investigation include the costs and benefits of shifts in pest management for non-GE producers due to the adoption of GE cops, the value of market opportunities afforded to organic farmers by defining their products as non-GE crops, the economic impacts of GE-crop adoption on livestock producers, and the costs to farmers, marketers, and processors of the presence of approved or unapproved GE traits and crops in products intended for restricted markets. As more GE traits are developed and inserted into existing GE crops or into other crops, understanding the impacts on all farmers will become even more important to ensuring that genetic-engineering technology is used in a way that facilitates environment, economic, and social sustainability in U.S. agriculture.
• Commercialized GE traits are targeted at pest control, and when used properly, have been effective at reducing pest problems with economic and environmental benefits to farmers. However, genetic engineering could be used in more crops, in novel ways beyond herbicide and insecticide resistance, and for a greater diversity of purposes. With proper management, genetic-engineering technology could help address food insecurity by reducing yield losses though its introduction into other crops and with the development of other yield protection traits like drought tolerance. Crop biotechnology could also address “public good” issues that will be undersupplied by the market acting alone. Some firms are working on GE traits that address public goods issues. However, industry has insufficient incentive to invest enough in research and development for those purposes when firms cannot collect revenue from innovations that generate net benefits beyond the farm. Therefore, the development of these traits will require greater collaboration between the public and private sectors because the benefits extend beyond farmers to the society in general. The implementation of a targeted and tailored regulatory approach to GE-trait development and commercialization that meets human and environmental safety standards while minimizing unnecessary expenses will aid this agenda (Ervin and Webb, 2006).