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Organic weed control and emergence of a new super weed

How does it affect the soil when the organic farmer control weeds mechanically? And when in the season is it best to start the fight against weeds? And is agricultural production threatened by a new super weed?

2021.07.08 | Camilla Brodam

Photo: Muhammad Javaid Akhter

Weeds are not that easy control. Conventional farmers can use pesticides, but are experiencing more and more problems with resistance. The organic farmers control weeds mechanically, but perhaps without knowing how it can affect soil and yield. And in recent years, new super weeds has emerged, can we fight them?

No side effects with mechanical control of root weeds in organic fields

Organic farmers have to rely on being able to control weeds mechanically rather than using pesticides like conventional farmers. In other words, methods are needed that can effectively control perennial weeds.

Mechanical treatment of the soil is often used for this, but how does it affect the soil structure, does it give rise to more or perhaps fewer disease attacks, and what about the grain yield?

All this was investigated in a 4-year trial in Norway.

“It is a rather interesting experiment because it is rare in the literature that there are several elements at the same time. Often, we only look at weeds or diseases, but here we have included several elements at once, so that we can see if the mechanical treatments have derived and undesirable effects on soil structure and grain diseases,” explains Associate Professor Bo Melander from the Department of Agroecology at Aarhus university.

Read more here.

Is rattail fescue the new super weed?

A new weed species has become a major problem in winter seed and seed grass in recent years. And knowledge about rattail fescue has been very limited. But at the beginning of the year, a new article was published which had examined the biology, phenology, competitiveness and effect of different weed strategies on weed species. 

“This is a relatively new weed species, which in the beginning was very local and only appeared in some specific crops, such as red fescue. But it has become much more common and reported as a problem on many areas over time and in many crops too, in particular winter cereals and grass seed crops,” says Professor Per Kudsk from the Department of Agroecology at Aarhus University in Flakkebjerg.

Read more here.

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