Little is known about the long-term contribution of cover crops to weed management in tillage- and herbicide-based systems.

Research questions

Do cover crops mainly filter weed species capable of setting seeds during the fallow period? Can cover crop biomass productivity explain differences in weed suppression among cover crop species? Does reduced weed seedbank density translate into lower weed biomass and higher crop productivity?

It is very common to use chemical herbicides to control weeds in maize. Considering the negative environmental impact of this practice and the societal pressure to reduce herbicide use, finding alternative solutions is desirable.

The diversification of the maize crop is a possible solution: sowing the maize in a (winter) partner crop, mowing the partner crop, and using the mulch for soil cover and weed suppression.

Yield gaps between organic and conventional agriculture raise concerns about future agricultural systems which should reduce external inputs and face an unpredictable climate. In the UK, the performance gap is especially severe for wheat that, as a result, has a small and shrinking organic acreage. In organic wheat production, most determinants of crop performance are managed at a rotation level, which leaves cultivar choice as the major decision on a seasonal basis.

No-till cropping systems with cover crops can improve soil health, but often rely on glyphosate, which is a contentious herbicide. In this study, we investigated whether a system based on the direct sowing of sunflower (Helianthus annuus) in the dead mulch of a roller-crimped hairy vetch (Vicia villosa) could be competitive with a system where glyphosate is also sprayed to terminate the cover crop and to control weeds.

On arable farms without livestock, nitrogen insufficiency can occur when cultivating nutrient demanding crops like maize. This can lead to yield losses and weed infestation. Use a green manure of winter field peas before growing crops that have a high nitrogen demand in the rotation.  Ploughing in winter field peas in spring can provide more than 100 kg of nitrogen to the following crop and increase yield. The improved development of the crop also leads to improved weed control.

The use of plant protection products poses numerous risks to the environment, including biodiversity.

The use of flame weeding can avoid herbicides and pesticides. In the leaflet "Flame weeding - Alternative weed control without herbicides" this weed control is presented.

As the negative health and environmental effects of chemical soil fumigation become more apparent, it is critical to devise safe, alternative methods of soil fumigation. Organic growers constantly struggle with weed control and need innovative, chemical‐free weed management techniques.