Réduire les herbicides en cultures de canne à sucre, à quel prix

Sugarcane is a main crop in Réunion, covering 54 % of the UAA (Utilized Agricultural Area) in 2021, with around 2,700 growers. This semi-perennial crop faces a major challenge in managing weeds, which can lead to significant yield losses. In this context, the CanécoH V2 project aims to reduce herbicide use while proposing viable farming systems. The study evaluates the performance of three herbicide-efficient systems for sugarcane cultivation across three different sites. These systems reduced the Herbicide Frequency Treatment Index (HFTI) by 50 % compared to the conventional system, while keeping weed coverage below the damage threshold (30 %). Cane yields and sugar content remained generally stable, although a slight decrease was observed. However, adopting these alternative systems led to a significant increase in labor time (+127 to +174 %) and costs (+53 to +139 %), primarily due to manual weeding and straw management. Adjustments are therefore necessary to improve the economic viability of these systems. Preliminary results nonetheless show that it is possible to cut herbicide usage by half while maintaining optimal production.