It is possible to control weeds effectively without using large quantities of herbicides. The trick is to lay the right herbicide application strategy and to mix in some tips gleaned from the world of organic farming. The result? Less herbicide use, reduced treatment frequency, less traffic in the field for mechanical weeding and – not least – minimal amounts of weeds in the crop.

How this is done in the most practical, efficient and economical way is what senior scientist Bo Melander from the Faculty of Agricultural Sciences, University of Aarhus, is working on. His work is part of ENDURE, an extensive EU-project that aims to optimise the use of pesticides in the EU.

Together with scientists and advisors from Italy, Holland, Germany and France, Bo Melander is working on a case study regarding weeds in maize.

- With the case studies we hope to demonstrate that it is possible to integrate the two sets of strategies so that weed control remains just as effective with a lower input of herbicides and has a smaller impact on the environment, says Bo Melander.

The strategy for the combined conventional-organic weed control includes four main points. The spraying frequency must be reduced, the amount of herbicide applied must be reduced, the applied herbicides must be less toxic and organic farming methods, such as mechanical weeding, must be used in cases where it is reasonable to do so.

- As far as possible, weed control methods familiar to organic farming will be applied but where these are insufficient we will use chemical methods, explains Bo Melander.

- For example, mechanical weeding in maize after the maize has sprouted can harm the crop. In this case we would use the chemical solution. On the other hand, you can harrow before the maize sprouts and again later, when the maize has reached a certain size – but only if the weeds are not overly big. In any case the weeds should never be allowed to grow too big if you want your weed control to be effective, says the senior scientist.

When the scientists have done investigating the relevant methods, they will prepare recommendations that can be used in all of the EU and which will be made available on ENDURE’s website.

- In the future the EU will probably support environmentally friendly farming even more, so the knowledge that we create will be very useful, says Bo Melander.

For more information please contact: Senior scientist Bo Melander, Department of Integrated Pest Management, Faculty of Agricultural Sciences, University of Aarhus, telephone: +45 8999 3593, e-mail: Bo.Melander@agrsci.dk

ENDURE, European Network for the Durable Exploitation of Crop Protection Strategies, is a so-called “network of excellence (NoE)” which is financed by EU’s 6th Framework Programme.

The aim of ENDURE is to create a European research network that will also exist after the funding of ENDURE ceases at the end of 2010. The research activities aim to achieve a better understanding of pest biology and the interaction between plants and their pests and, based on this knowledge, to develop new, innovative control strategies in which dependence on effective pesticides is reduced compared to the present. This can be achieved by combining analytical and system-based approaches and by promoting collaboration between biologists, agronomists, economists and sociologists. Another important goal of ENDURE is to ensure that new knowledge is communicated to all relevant parties: farmers, advisers, the industry, politicians and, not least, consumers.

Read more about ENDURE at www.endure-network.eu .

Tekst: Janne Hansen