Plantain mycorrhization with native consortium of arbuscular mycorrhizal fungi (AMF) induce solubilisation of metals (Fe2+ and Al3+) in soil from Azaguié (south-east of Côte d’Ivoire)

Abstract

New agroecological practices propose to manage soil fertility using soil microorganisms such as arbuscular mycorrhizal fungi (AMF). However, few studies have been conducted on the impact of plantain mycorrhization and metal (Fe²⁺ and Al³⁺) solubilisation in soil. This study evaluates the effectiveness of native AMF on plantain growth and metal leaching from soil. Trap plants (maize, sorghum and cowpea) were grown to produce various inoculums. Then, plantains were grown under controlled conditions, with six treatments (control, plantain without inoculum, plantain with maize root inoculum, vigna root inoculum, sorghum root inoculum and mixed root inoculum) replicated five times. Growth parameters were measured, and the rate of plantain root colonization was evaluated by determining the frequency or intensity of infection. The contents of metals in leached solutions were analyzed using ICP-OES. Results indicated the rate of plantain roots colonization by fungi was not significantly different between the different treatments. Plantain biomass remained very low whatever the treatment. However, plant inoculated with vigna roots inoculum had the highest biomass while plant inoculated with sorghum root inoculum showed the lowest biomass. Leached solutions from soils with inoculated plants had on average a pH value of one pH unit lower than leached solutions from soils without inoculum. In addition, plantain mycorrhization can promote the leaching of Fe²⁺ from the soil by acidification, whereas the difference between treatments was not significant for the concentration of Al³⁺ in solutions. These results suggest that the association of plantain with microorganisms remains a way for agroecological banana production in Côte d’Ivoire.