GM Free Cymru

OU study of farmers and GM crops: "how you pick your survey respondants predetermines the outcome"


Re the dispute arising from the ESRC press release about this expensive (£131,000) and highly misleading piece of research by an OU team, this Open Letter by Ann Clark makes some cogent points on scientific method, and on some of the GM "facts" cited by the research authors -- regarding supposed profitability, yield, environmental benefits etc. Particularly chilling is her revelation that in western Canada the seed merchants have systematically removed non-GM canola seeds from their catalogues to the point where there is only one left -- as against 48 GM herbicide-tolerant cultivars.


29 February 2008

re: "Farmers are Upbeat About GM Crops"

As I tell my students, how you frame the question predetermines the range of possible answers. This article demonstrates the corollary: how you pick your survey respondants predetermines the outcome. Did the authors of the research - Professor Andy Lane and Dr Sue Oreszczyn - actually intend their findings to be released now, or was it an inadvertent disclosure? Perhaps this small and patently selective sampling of farmer opinion - "30 large-scale, commodity farmers -- not those mainly involved in organic growing" - was just a preliminary effort, to be followed up by a larger, statistically sound sampling? Or perhaps all British farmers are large-scale commodity growers, such that this small group could be considered representative?

I can certainly sympathize with British farmers about the difficulty of getting good, unbiased production advice in a vacuum of government extension support. Our farmers are in the same boat, if that makes you feel any better.

But what I cannot fathom is how British academics can still be quoted as saying that GM crops allow farmers to grow "high- quality food profitably", in an "environmentally sensitive way", and to attain "high yields while using less herbicide".

Perhaps they were misquoted. Roughly 99% of GM land on the planet is sown to just two traits - herbicide tolerance (HT) and Bt, which causes plants to synthesize their own insecticide. Nothing about quality.

Objective evidence of profitability is equally sparse, particularly if one factors in the lemon effect of lost markets due to the global rejection of GM. British growers might want to look for an article by Mauro and McLaughlin (in press: "Farmer knowledge and risk analysis: post release evaluation of herbicide tolerant canola in Western Canada") when it comes out in the journal Risk Analysis. This is the first ever publicly available survey, in a peer reviewed journal, of how Canadian farmers have been impacted by GM technology. It includes a quote by a Canadian farmer, who said "The loss of [European] markets due to GM had a huge financial impact. This was likely larger than cost of controlling volunteers or benefit of easy weed control”.

This same 2003 survey of 370 farmers found that greatest cited benefit among technology users (n=298) was operational, including timing and efficacy of weed control, facilitating farming of a larger landbase. Among 10 ranked benefits, increased yield was 6th and increased revenue ranked last. Among 10 cited risks, of greatest concern were loss of markets, loss of farmer rights under the Technology Use Agreement, higher seed costs, and lawsuits. Remember Percy Schmeiser?

So how about yield? Pay attention, British growers, to a recent USDA retrospective on GM in the US, which stated “Currently available GE [genetically-engineered] crops do not increase the yield potential of a hybrid variety. In fact, yield may even decrease if the varieties used to carry the herbicide-tolerant or insect-resistant genes are not the highest yielding cultivars.” (Fernandez-Cornejo, J. and M. Caswell. 2006, The First Decade of Genetically Engineered Crops in the United States. USDA- ERS EIB11/). Likewise, researchers with Agriculture and Agri-Food Canada (AAFC) summarized the Canadian experience with GM crops. Beckie et al. (2006 "A decade of herbicide-resistant crops in Canada". Can. J. Plant Sci. 86:1243-1264) cited a 2-year AAFC trial over 5 western Canadian locations where HT outyielded conventional canola weed control practices in just 6 of 30 contrasts, all occurring at sites and years of particularly problematic weeds. They also cited evidence from public variety trials in Ontario, where much of the Canadian corn and soybean are grown, showing not an increase but a 4% yield decrease in GM soybeans and the absence of yield benefit from GM corn. So, let's skip the 'higher yield' mantra and stick with the scientifically defensible evidence. Somebody might as well learn from our experience.

Less herbicide? Environmentally sensitive? As of 2008, a total of 63 weed biotypes spread over 13 species are now tolerant to glyphosate, the active ingredient in Monsanto's Roundup Ready herbicide. Of these, 41 were detected in soy or cotton fields starting in 2000 ( Of the 41, 32 were reported from the US, with the rest predominantly from Brazil and Argentina, paralleling global use patterns of HT technology. The evolution of weed resistance in GM crop fields has increased - not decreased - rate and frequency of application of herbicides, and obliged tank-mixing with other herbicides to cope with intractable weeds. We now use more - not less - herbicide.

So if it doesn't actually do what was promised - apart from simplifying the process of weed control, then why are so many North American farmers growing GM crops? Beckie et al. (2006) reported that planting choices for western Canadian canola producers had simplified down to 1 non-herbicide tolerant (HT) cultivar and 48 private sector HT cultivars, which includes mutagenized as well as transgenic HT cultivars. Was this because they were all so pleased with what HT is doing for them, or was it just safer than becoming the next Percy Schmeiser? Next time British farmers or policymakers hear that 95% of western Canadian canola plantings are HT, they might want to ask themselves if this is a fate they want for themselves.

E. Ann Clark, Ph.D. Associate Professor Department of Plant Agriculture University of Guelph Guelph, Ontario, Canada N1G 2W1 (519) 824-4120 Ext. 52508