Contribution des méthodes de lutte mécanique au désherbage intégré des grandes cultures oléagineuses

Abstract

The integrated approach of weed management refers to a combination of direct and indirect methods in order to limit chemical applications. In oilseed rape, sunflower and soybean, mechanical weed control can be an alternative or a complement to herbicides and should take progressively a larger place in the direct weed control options, taking into account of the policy of restriction of chemical use. CETIOM launched a research program to assess, in different backgrounds, the selectivity and the efficacy of three tools, used either alone or combined with herbicides: the rotary hoe, the finger weeder and the in-row hoe. As an alternative or a complement to herbicides, mechanical weed control strategies were selective enough for oil crops if they were used in appropriate conditions (crop stage, soil surface moisture, adjustments of the tools). Linked with long term preventive measures to maintain weed population at a low level, they could be as efficient as herbicides but with an irregularity and strongly dependent on weed development stage. These techniques could be economically competitive but require often more working time. Mechanical management can thus be an answer to some of the new requirements of the agricultural context but operator skill, experience and knowledge are critical to success. Introducing these weed control methods in a farm requires a deep change of state of mind which appears today as a major restraint for the farmers.