1st December 2002
Economic and Environmental Impacts of First Generation Genetically Modified Crops, Lessons from the United States
This paper brings together a wide reading of the current agricultural research on genetically modified organisms, and data on planting, use rates and yields, focusing specifically on three crops: Roundup Ready (RR) soy, Bt cotton and Bt corn. The consolidation of information is conducted with a view to drawing out the implications for crop management strategies in the U.S. and Argentina—the two biggest users of the new technologies. The paper first looks at rates of adoption, herbicide use rates and yield data.
As well, the paper examines the environmental effects of current practice. Those effects include several pieces of environmental good news, including benefits to soil conservation from new cropping techniques, and the benefits of using glyphosate in combination with RR soy, replacing more toxic and persistent herbicides. But the effects of current practice also have some worrying implications. Poor management of the new technologies risks undermining their effectiveness, while selection pressures lead to weed and pest shifts as well as increased resistance. The study predicts that in Argentina, with current levels and patterns of use, these problems should be surfacing soon, and may already exist.
The study also looks at emerging issues that may impact the performance of RR soybean cultivars. New research shows that the process of making soy cultivars Roundup Ready may also impair their physiological performance under certain types of stress and growing conditions. Other research looks at the changes in soil microbial communities that are brought about by high levels of glyphosate use. Particularly worrying are the observed links between glyphosate use and increased levels of Fusarium—a fungus associated with a number of crop and livestock diseases. There are also observed negative effects of glyphosate on soybean root development and nitrogen fixation.
Based on what we know today, the consequences of these environmental impacts and ecological responses are largely economic, played out in terms of crop yields and costs of crop production. The study makes a number of recommendations aimed at maintaining the benefits of the new technologies, including reducing the ratio of acreage devoted to RR vs. conventional soybean varieties, diversifying weed management systems and technologies, and reducing the over-reliance on any single strategy.