S21 - Session O3 - Alternative weed management in organic banana agrosystems

Authors: Steewy Lakhia *, Marc DOREL, Raphaël ACHARD

In organic farming, the use of herbicides is prohibited. It is therefore necessary to mobilize alternative techniques for weed management. Currently, banana farms certified in organic farming can mobilize four types of solutions for weed management i) mowing techniques, ii) mulching with crop residues or with recyclable and reusable cover, iii) installation of cover plants for weed growth regulation, and iv) selective weeding in the spontaneous vegetal cover. However, the mobilization of these alternatives may reveal negative environmental impacts and increase the hardships and the cost of agricultural work. The aim of the study is to evaluate the competition impact of weeds on the banana growth and the impact of different weed management option in organic banana agrosystems. In a first experiment in Martinique, we compared different mechanical weed control options with a conventional herbicide control and evaluated weed cover competition with the banana crop for nitrogen. A Weed cover managed by mowing demonstrated a competition for mineral nitrogen in the soil during the first cycle, but no additional negative impact was observed during the second banana cycle. Mowing tools promoted grass species diversity in the cover while compacting soils. Cover crop was an effective in weed regulation but required a significant cost to set up. Mulching with vegetal material or polypropylene cover resulted in good weed control except against the lianas. This option is suitable for weed control during the beginning of the first cycle. Afterward, a possible option is the selective weeding, which consists the manual elimination of all the plants considered to be harmful for the crop.