MODIFIED sugar beet is far more environmentally friendly than conventional beet. So concludes a controversial new analysis that is the first to measure the wider impact of such crops, including their contribution to global warming, damage to the ozone layer and toxicity to aquatic life.
鈥淥verall, herbicide-resistant GM beet was 15 to 50 per cent better for the environment, depending on what impact was being measured,鈥� says Richard Phipps of the School of Agriculture at the University of Reading in Berkshire, UK.
Phipps and colleague Richard Bennett say the benefits arise mainly because farmers spray much less weedkiller and pesticide onto GM beet, less often. Thus saving a lot of tractor fuel and reducing the impact on global warming, for example.
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The findings contradict the recently completed 鈥渇arm-scale evaluations鈥� in the UK, the largest trials done to compare the effects of GM and conventional crop systems on farmland wildlife (New 杏吧原创, 25 October, p 21 and p 46). In these, GM beet and oilseed rape turned out to be worse than non-GM counterparts. Maize with GM resistance to a particular weedkiller did better than non-GM maize, but the result may become a moot point as the EU is soon to ban the use of that weedkiller on conventional maize.
In Phipps鈥檚 and Bennett鈥檚 analysis, they gathered data from published literature, farmers and real field experiments on GM and conventional beet. They measured various parameters prescribed in an internationally accredited standard, including the energy used in making the weedkiller, and the amount of diesel used by tractors spraying crops. The analysis also catalogues all physical resources consumed and the impact of any pollution.
Phipps says their experimental approach, which they call 鈥渓ife-cycle analysis鈥�, could easily be used to test the environmental impact of other farming systems. 鈥淭here鈥檚 absolutely no reason why the same methodology couldn鈥檛 be applied to organic or no-till systems of agriculture.鈥�
He argues the analysis is more holistic, and gives a broader picture than the farm-scale evaluations, which simply examined effects on wildlife. 鈥淲e鈥檙e not having a pop at the farm-scale evaluations, which were brilliant,鈥� he says. 鈥淲e鈥檙e simply saying they looked at only one component of the system.鈥� But Les Firbank, coordinator of the farm-scale evaluations, says that each environmental impact may have a very different effect on the countryside. Helping birds recover might be considered far more important than conserving tractor fuel, for example.
Phipps presented his preliminary findings last week to the UK government鈥檚 Advisory Committee on Releases to the Environment.
