Scientists refute aspects of UK Farm Scale GM study

A group of leading international agricultural and food scientists says increased food production by GM herbicide-tolerant crops could actually benefit the environment and enhance biodiversity in Britain and Europe by allowing unused farmland to rededicated as conservation reserves.

In a letter to the journal Nature Biotechnology, Prof Bruce Chassy, assistant dean for biotechnology outreach at the University of Champaign-Urbana in Illinois, and eight other scientists, strongly criticised international media coverage of the results of the world's largest study of GM crops, the UK Farm Scale Evaluation (FSE) trials.

The letter's signatories included Dr Chris Preston, director of the Cooperative Research Centre (CRC) for Weed Management in Adelaide, and the CRC's former director, Dr Rick Roush, now at the University of California, Davis.

The writers said the published findings of the UK Royal Society on the FSE trials did not justify the conclusion of many media and environmental groups that GM crops were environmentally damaging and bad for biodiversity -- particularly bird populations.

Many UK media reported that the results of the large-scale field trials of GM sugarbeet, rapeseed (canola) and maize sounded the death knell for GM agriculture in Britain.

Chassy et al said media discussion had assumed that the availability of weeds and weed-associated invertebrates eaten by birds were the dominant factors determining bird populations -- which was clearly not proven -- and that biodiversity could be equated with insects and weeds in crop fields.

In fact, the study had not counted birds, nor assessed the impact of GM crops on biodiversity. Moreover, they ignored the fact that weed populations on farms were the result of management strategy, not the GM status of the crop.

"For example, an organic farmer who thoroughly hoes a field would be equally effective at destroying potential bird feed and habitat," the letter said. "A farmer who uses conventional herbicides effectively along with mechanical tillage might do likewise. Thus, if leaving more weeds in the fields really were deemed an appropriate public policy for UK farmers' fields, farmers would simply need to be mandated to use less herbicide, rather than having their right to use GM crops curtailed.

"Indeed, the studies demonstrated that weeds and some insects were more common in oilseed rape crops, GM or conventional, than in beet or maize crops. Therefore, a more effective method of increasing the numbers of arable weeds and insects in crops would be to legislate crop choice."

The writers also pointed out that after seven years of GM crops in the United States, agriculture had changed in ways that broadly benefited the environment and biodiversity.

Herbicide-tolerant crops had seen no-till practices rapidly and widely adopted, reducing energy inputs and soil erosion, and enhancing soil structure, populations of microbes and invertebrate species, and organic matter content -- changes that actually improved the habitat for birds and mammals.

The writers said GMHT crops "may be one of those rare technologies that improves yield and product quality while reducing the environmental footprint of agriculture".

Besides enhancing the efficiency of Europe's system of farming in small spaces, judicious use of herbicides on both conventional and GM crops could maximise food production on existing farmland.

"With the resulting increased food production, society could dedicate the land thus conserved as natural reserves, where many species could truly flourish, providing even greater biodiversity --after all, farmland has never been intended to be a natural habitat for any form of life except crops and farmers," they said.

"The publication of the FSEs demonstrated, as the investigators themselves foretold, that GM critics will seize any opportunity to continue their anti-GM campaign. News coverage of the FSE results also confirms that certain parts of the media may be more interested in sensationalism than in getting the story right.

"On a scientific basis, the most damning result from the FSEs is that GM crops can make it too easy to control weeds! Perhaps most disappointing to us as food and agricultural scientists is that the FSEs have created an unwarranted, negative impression of GM technology while answering all the wrong questions."