E-Letter responses to:

n-focus: Robert F. Service AGBIOTECH: A Growing Threat Down on the Farm Science 2007; 316: 1114-1117 [Summary] [Full text] [PDF]

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Can Herbicide-Tolerant Soybeans Save Topsoil?

Bill Freese, Charles Benbrook, Doug Gurian-Sherman   (12 October 2007)

Can Herbicide-Tolerant Soybeans Save Topsoil? 12 October 2007
Bill Freese, Science Policy Analyst Center for Food Safety, 660 Pennsylvania Avenue, SE, Suite 302, Washington, DC 20003, USA, Charles Benbrook, Doug Gurian-Sherman Respond to this E-Letter: Re: Can Herbicide-Tolerant Soybeans Save Topsoil?	In "A growing threat down on the farm" (News Focus, May 25 2007, p. 1114), R. S. Service suggests that glyphosate-tolerant (GT) crops promote use of soil-saving no-till or reduced-till agriculture ("conservation tillage"). Yet, a 2002 study by the Economic Research Service of the U.S. Depatrtment of Agriculture (1) shows clearly that the dramatic increase in conservation tillage for soybeans (from 25 to 60% of U.S. soy acres) occurred from 1990–1996. GT soy (the major GT crop) was introduced in 1995, and accounted for less than 10% of soy acres in 1996 (2). Furthermore, use of conservation tillage declined slightly from 1997–1999, when GT soy increased to over 50% of soy acres. On the basis of an econometric analysis, the authors conclude that, "using herbicide-tolerant [soybean] seed did not significantly affect no-till adoption" (3). Rather, farmers already using no-till were more likely to adopt herbicide-tolerant seeds. Thus, credible data suggest that it is incorrect to credit GT soybeans with saving topsoil. Bill Freese Science Policy Analyst, Center for Food Safety,660 Pennsylvania Avenue, SE, Suite 302, Washington, DC 20003, USA. Charles Benbrook Chief Scientist, The Organic Center, 90063 Troy Road, Enterprise, Oregon 97828, USA. Doug Gurian-Sherman Senior Scientist, Union of Concerned Scientists, 1707 H Street, NW, Suite 600, Washington, DC 20006, USA. References 1. J. Fernandez-Cornejo, W. D. McBride, Adoption of Bioengineered Crops, U.S. Dept. of Agriculture, Economic Research Service, Agricultural Economic Report No. 810, May 2002. (www.ers.usda.gov/publications/aer810/aer810.pdf). See Figure 11 on p. 29 for percentage of soybean acres grown with conservation tillage from 1990-1999. 2. For percentage of soybean acres planted to glyphosate-tolerant varieties, see "HT soybeans" in graph entitled "Adoption of genetically engineered crops grows steadily in the U.S.," at www.ers.usda.gov/Data/BiotechCrops/. Note that GT soybeans are the only type of herbicide-tolerant (HT) soybean grown commercially. 3 J. Fernandez-Cornejo, W. D. McBride, Adoption of Bioengineered Crops, U.S. Dept. of Agriculture, Economic Research Service, Agricultural Economic Report No. 810, May 2002. (http://www.ers.usda.gov/publications/aer810/aer810.pdf), p. 29.