PHYSICAL AND CULTURAL WEED CONTROL – STATUS AND FUTURE DIRECTIONS

Summary

Non-chemical methods for weed control play an important role for the management of weeds in organic cropping systems in Europe. With the expansion of the organic area in recent years, more research has been conducted to develop new methods and improve management strategies. Currently, weed harrows, rotary cultivators and inter-row cultivators are the principal methods used for full-width treatments in large agricultural crops, such as cereals, oil seed rape, maize and pulses. The mechanical methods are often combined with cultural measures, e.g. stale seedbeds, delayed sowing, placement of fertilizers etc., to benefit from the additive and sometimes even synergistic effects of combining direct and cultural methods. In row crops, such as sugar beets and horticultural crops, thermal and mechanical methods are mostly combined to remove as many weeds in the rows as possible in order to minimize the need for manual weeding. Weeds growing between the rows are easily controlled by inter-row cultivation. Robotic weeding for intra-row weed control is now possible for transplanted crops, and inter-row hoes have been equipped with GPS-systems and cameras for optimizing precision and steering. Works on new GPS technology is currently focusing on seeding systems with the ability to create parallel or diamond crop establishment patterns, which enable inter-row hoeing to be conducted in different directions. So far, non-chemical methods have had little uptake in conventional farming but national and EU-based legislative initiatives may change the situation radically in the near future. Several European countries have launched pesticide action plans and the EU a new directive for the implementation of integrated pest management (IPM); all aiming for minimizing the reliance on herbicides. This is expected to accentuate the need for non-chemical methods.