GM Crops Shown to Decrease Damage to Environment

The increase in cultivation of herbicide-resistant GM Canola (also known as rapeseed) in Canada has led to a significant decrease in herbicide use, says research published in the journal Pest Management Science. This has led to a decrease in the environmental impact of weed control and could have similar effects elsewhere in the world.

Between 1995 and 2000, the amount of GM Canola grown increased from 10% to 80% of the total Canola area, causing herbicide use to decrease by over 40%. The environmental impact of the herbicides, calculated from human and animal toxicity and persistence in the environment, was found to have decreased by 36%

“This is a useful quantification of the direct effects [of growing HR canola]” says John Pidgeon, Member of SCI’s (Society of Chemical Industry) Agriculture and Environment Group. These results confirm that in terms of pesticide use, growing HR Canola does benefit the environment.

The decrease in herbicide use was attributed to the fact that herbicide resistant crops require only one or two applications of a single broad-spectrum herbicide such as glyphosate, while unmodified crops need several applications of combinations of herbicides. In addition, the powerful broad-spectrum herbicides can be targeted specifically to weed-infested areas while the crop is growing, rather than being applied to the whole field before planting.

These findings challenge the view of some environmental pressure groups that herbicide-resistant crops will increase the reliance on herbicides. Although broad-spectrum herbicides have come under criticism for higher toxicity, the small amounts applied compared to other herbicides result in a net benefit to the environment. The reduction in herbicide use also reduces re-cropping restrictions, as there is a lower herbicide residue in the soil.