Independent Reports Yield Conflicting Conclusion on Environmental Effects

Both reports are analyses of other data sources and studies conducted during the five years since Roundup Ready's introduction. However, they draw conflicting conclusions, and thus do little to clarify the debate on the environmental effects of genetically modified crops. But both highlight the need for definitive, well-documented, large-scale monitoring studies, and an education program for farmers to promote sustainable agriculture.

Transgenic soybeans have been on the market for five years, but their impact on the environment is still under debate.

Roundup Ready soybeans have been genetically modified by Monsanto Co. to be resistant to glyphosate, a broad-spectrum herbicide sold by Monsanto as Roundup. This allows farmers to spray without harm while the crop is growing, when weeds are a more serious threat. Monsanto claimed this would reduce herbicide use by up to 30%, but environmental groups argued the genetically modified crop would encourage farmers to douse fields with herbicides, increasing their use up to threefold.

The first report, entitled "Troubled Times Amid Commercial Success for Roundup Ready Soybean," was written by biotechnology advisor Charles Benbrook at the Northwest Science and Environmental Policy Center in Idaho. "Roundup Ready soybeans clearly require more herbicides than conventional soybeans," concludes Mr. Benbrook. He also claimed the yield of Roundup Ready soybeans can be up to 10% less than the yield of conventional soybeans.

The second study, "Environmental and Agronomic Effects of Glyphosate Tolerant Soybean in the U.S.," was conducted by biotechnology consultant Piet Schenkelaars and the Dutch Center for Agriculture and the Environment. It was financed by the Dutch Product Board for Margarines, Oils and Fats, the marketing board for the processing industry, and supervised by a remarkably broad committee. The committee included representatives from the Dutch biotechnology-industry association, Greenpeace, and the Netherlands Society for Nature and Environment. Roundup Ready soy cultivation across the U.S. has led to "a modest reduction in herbicide use," concluded the Dutch researchers. The report also said an increase use of glyphosate over other herbicides is having a positive effect on the environment, but that the available studies about the impact on biodiversity and yield are too small to be useful.

Both reports have, in the main, analyzed the U.S. Department of Agriculture's Agriculture Chemical Usage Survey, a U .S.-wide study that evaluated herbicide use between 1995 and 1998, based on interviews with 8,800 farmers. According to that study, the total amount of herbicide used on all soybeans, both transgenic and conventional, was one pound per acre in 1995, 1.18 pounds per acre in 1997, and 1.06 pounds per acre in 1998. More recent figures show one pound per acre for 1999. The U .S. agriculture department researchers said no distinction was made between transgenic and traditional soybeans in part because the differences would be too small to be statistically insignificantly in many cases. Messrs. Benbrook and Schenkelaars have interpreted the department of agriculture data in different ways.

Mr. Benbrook noted the increase in herbicide use in 1998 compared to 1995, arguing that the 1996 introduction of Roundup Ready soy is responsible. But he has also taken the raw data from the 1998 interviews to show that an average of 1.22 pounds per acre was used on genetically modified soybean in 1998 compared with 1.08 pound per acre for conventional soy bean-l1% more. He also noted that in six U .S. states, including Minnesota, total herbicide use on Roundup Ready soybeans in 1998 was as much as 30% greater than that for conventional varieties.

Meanwhile the Dutch researchers focus on the 10% drop of total herbicide use between 1997 and 1998. Although several factors could influence herbicide use, they estimate that the introduction of Roundup Ready soybean is responsible for a "reduction in herbicide use of somewhere between 0 and 10%."  The factors include different weather conditions, a switch to the so-called low-dose herbicides, fewer weeds, the adoption of precision-weed management, and the new Roundup Ready soybean.

Both groups are critical of the other. For instance, Mr. Benbrook said the 10% decrease in herbicide use between 1997 and 1998 is misleading. To compete with Roundup Ready soybeans, he said, chemical firms drastically reduced the price of more concentrated herbicides and that the 10% decrease recorded between 1997 and 1998 is actually the result of farmers adopting these low-dose herbicides. Meanwhile, the Dutch group said Mr. Benbrook's report "doesn't provide insight into the statistical approaches applied, nor in their limitation," and they agree with the U.S. agriculture department that using raw data to draw conclusions at the level of states and even fields doesn't hold up statistically. But Mr. Benbrook claimed the U .S. agriculture department chose not to distinguish between transgenic and traditional soy because the result could pose problems for industry.

Janet Carpenter from the U.S. National Center for Food and Agricultural Policy has independently analyzed the same U.S. agriculture department study. According to Ms. Carpenter, the introduction of Roundup Ready soybean has had little change on the total amount of herbicides used. An average of one pound per acre of herbicide was used both in 1995, before the introduction of Roundup Ready soybeans, and in 1999. While there was a reduction in 1998, which the Dutch researchers stressed, there was an increase in 1996 and 1997.

By Marianne Heselmans Wall Street Journal

iGreen comment

This looks like a win for the GM soybean producers. Even the Benbrook report admits that herbicide use fell in 1998. He claims that all farmers caused it by moving to low dose herbicides in response to competition from Roundup ready soybeans, rather than that Roundup Ready users themselves used lower doses. Either way the environment benefits. More importantly, farmers will only go on paying for Roundup ready if it is in their economic self-interest, i. e. if it really increases yields or reduces herbicide costs, or both. Watch this space.