Multidisciplinary assessment of two organic banana production systems in Martinique

A drastic reduction in pesticide use over the last 20 years in Martinique has been possible thanks to the deployment of banana in vitro plantlets, fallow rotations and cover crops, but this agroecological transition entails additional costs for growers. Certified organic production could provide access to higher prices, but technical challenges for organic production in humid zones need to be addressed. In 2018, the BANABIO research programme set up two organic systems: 1) a bio-intensive banana monoculture (BI), and 2) a bio-diversified banana-cocoa-legume service tree association (BD) compared with a conventional system (CO). This trial, set up in a complete randomized block design, was assessed by a panel of specialists who examined yield, nutritional status of the soil and bananas, soil biodiversity, pest and disease pressure, and production costs. The results after three harvests showed a 16% gross drop in yields under organic farming conditions. More specifically, the gross agronomic yield was 42.1 t ha^‑1 for the CO system, as opposed to 35.1 t ha^‑1 for the BI system. In addition, the cycle length was on average 6 weeks shorter in the CO system. Black Sigatoka pressure was more intense in the organic systems as indicated by the number of leaves at harvest averaging 2.1 in the CO system versus 1.4 in the BI system. Nonetheless, soil biological processes and biodiversity were promoted in the organic systems. Due to weed restitution, the BD and BI systems had higher levels of C returned to the soil and our results showed that soil carbon concentration and earthworm biomass increased by 13 and 230%, respectively. The organic systems entailed very high production costs (€ t^‑1) of around +37% when comparing the BI system with the CO system over the first three cycles. Mechanical weeding (cost × 2.4) and organic fertilizers (cost × 2.4) were the main reasons for increased expenditure. quantifying the increase in income that could be derived by the producer from selling organic bananas is still to be assessed but given the important extra cost linked to organic banana production, organic farming is likely to be unprofitable in the current regulatory and economic context of the French West Indies.