Sep 19, 2002

Coexistence

Send

Conventional agriculture and the cultivation of genetically modified crops

Coexistence: The threshold is the key

The European Commission has commissioned several studies to calculate whether coexistence between conventional, organic and GM farms is possible in European agriculture. The sticking point is the threshold for admissible traces of genetically modified organisms (GMOs). The lower the threshold, the more complex and expensive it will be to respect it. A zero percent tolerance is, however, not achievable.

Many people are afraid of it. For others it is a biological truism: if genetically modified crops were to be cultivated in Europe, it would not be possible to keep ‘conventional’ and genetically modified farming completely separate.

There is much speculation about the levels of possible GMO traces in conventional and organic products. Some people fear that after a while ‘GM-free’ farming will no longer be possible. Consumers are worried about their freedom of choice.

Calculation models and scenarios. The JRC study

How might the cultivation of genetically modified crops affect conventional agriculture? Is coexistence between green genetic engineering and farming that specifically aims to be ‘GM-free’ possible? The European Commission has commissioned six individual studies. The results have now been summarised by the Joint Research Centre (JRC).

The scenario: Working on the assumption that in a certain region cultivation of GM crops will start at 10% and later rise to 50%, various scenarios were calculated for three crop plants that are widely grown in Europe:

  • Oilseed rape for seed production
  • Maize for use as food and feed
  • Potatoes for direct consumption and for processing

The questions: Based on existing data and expert estimates, the aim was to carry out model calculations to find answers to the following questions:

  • What level of contamination from GM plants is to be expected in the various conventional products?
  • Is it possible in principle to achieve a set threshold for unwanted GM contamination?
  • What measures are necessary to achieve the thresholds and what do they cost?
  • Thresholds: The scenarios were calculated for various possible threshold objectives.

Thresholds according to the current proposals of the European Commission:

  • Rape seed: 0.3%
  • Maize as food and feed: 1%ยท
  • Potatoes as processed or unprocessed food: 1%

Thresholds according to the views of organic farming, for which genetic engineering applications are not admitted:

  • For all products: 0.1% (technical limit of detection)

The simulation calculations for the various scenarios produced a different picture for each of the three crop types.

Rape seed: high costs for low GMO levels

For rape seed production, there are no fundamental difficulties for conventional farms to achieve a threshold of 0.3 per cent. What is needed is a suitable crop rotation.

However, to achieve this aim in organic farming, further measures are necessary, and these lead to higher production costs. The reason for this is volunteer rape (oilseed rape plants that grow outside the relevant cultivation area, usually the following year after a crop rotation), which is much harder to control in organic farming (no herbicides allowed).

In all scenarios, a threshold of 0.1 per cent can be achieved only with great effort. Cost increases of up to 40 per cent can be expected.

Suitable measures suggested for lowering the GMO levels are: 300m permanent isolation distances, sowing in the spring (reduces volunteer rape), longer rotation times.

Maize: 1% threshold for organic farms not a problem

For maize, the main source of GMO contamination is outcrossing. For small fields and fragmented agriculture, the cost of avoiding GMO incrossing is greater than for large-scale farming.

Organic farms have no problem achieving a threshold of one per cent for their maize products. This is because of the high purity of the organic seed and procedures that have already been put in place to separate conventional and organic products.

In particular with an assumed GMO cultivation level of 50 per cent, conventional farms can only achieve the one-percent threshold if they take certain precautions – e.g. respecting certain separation distances or planting varieties that flower at different times.

A threshold of 0.1 per cent appears to be unattainable in all scenarios. This view is based on unavoidable traces of GMOs in maize seed.

Potatoes: few problems, but still not 0%

Because of their biological characteristics, outcrossings among potatoes – unlike with maize or oilseed rape – are not a problem. A threshold value of one per cent in potato products is attainable in all scenarios without the need for any additional measures.

However, a GMO level of 0.1 per cent is likely to be difficult in practice. Firstly, there could conceivably be GMO traces in the production of seed potatoes, and secondly mixing during transport, storage and processing cannot be completely ruled out.

Attaining 0.1 per cent is not ruled out entirely, but there is not enough data to estimate the effectiveness of suitable measures, e.g. the development of separate logistic and processing systems.

Trend forecast: The JRC study findings can be generalised only to a certain extent. The authors point out that in many places there was not a sufficient body of data on which to base their model calculations. The study provides trend forecasts, rather than confirmed results.