Apr 15, 2010

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USA: Genetically modified plants have the potential to reduce ecological damage

The cultivation of genetically modified plants in the USA benefits both farmers and the environment. However, these advantages do not always apply and can even decline with time. This is the conclusion of a current report of the National Research council (NRC), which has now been published by the National Academies of the USA. To be able to use the full economic and ecological potential of GM plants, suitable tools need to be developed to detect the possible effects.

In the USA, genetically modified plants are grown on about half of the field acreage; for soya, maize and cotton, the proportion of GM varieties is 80%. In 2008, the NRC commissioned an independent non-profit organisation, a ten-man committee of scientists, economists and sociologists, to investigate the consequences of the cultivation of GM plants since 1996.

With the now published study, a comprehensive evaluation of the economic, ecological and sociological effects of the agricultural production of GM plants is available for the first time.

With their decision to grow GM plants, most companies have achieved higher harvest yields or reduced costs for pesticides or deployment of machines. At the same time, according to the NRC report, in comparison to the conventional agriculture practiced until now, cultivation of GM plants reduces environmental pollution.

As a result of the large-scale cultivation of Bt-plants (primarily maize and cotton) that possess resistance to certain pests, less insecticide is deployed for pest control.

In addition, the almost comprehensively used system of herbicide-resistant plants and the corresponding complementary herbicide , in particular for soya beans, has leveraged processing approaches that conserve the soil. Through the improved control of weeds, many farmers have to plough less. This enhances the quality and water retention of the soil and reduces erosion.

Using GM plants, less pesticides and herbicides, which find their way into the soil and water courses, need to be used. “The improvement in the quality of the surface water could be the greatest advantage of the cultivation of GM plants” said David E. Ervin, Professor for Environmental Management and chairman of the NRC committee. However, a suitable infrastructure is lacking for measuring such an effect.

To preserve these advantages for the environment in the future, the committee is asking farmers to abide by the appropriate regulations for good agricultural practice. For example, it warns against the excessive use of the herbicide component glyphosate , which is used for weed control when cultivating herbicide-resistant crop varieties. As a consequence of repeated deployment of the same active component, in the USA, nine species of weed have already developed resistance to glyphosate. GM species will lose their effectiveness if the farmers do not also adopt other concepts of combating weeds.

“We urgently need a better comprehension of how green gene technology affects agriculture and the environment” said Ervin. That will be particularly essential when in future new genetically introduced traits are available and GM varieties of other plant species come onto the market.

Assessments of the social consequences should also be taken into consideration. As with similar leaps in technology in agriculture, with green gene technology it is also to be expected that small, economically weaker businesses will no longer be able to be competitive, particularly when they do not want to cultivate GM plants or cannot afford the expensive patent-protected GM seeds.

The members of the NRC committee are appointed by the National Academies of the USA according to expertise and experience. They have to honour the academic standards aimed at excluding possible conflicts of interest. All members of a committee have to agree on a report. Like all NRC reports, the report on GM plants had to be examined before publication by external specialists.