Département d’Agropédologie, Laboratoire d’Amélioration de la Production Agricole, Unité de Formation et de Recherche en Agroforesterie, Université Jean Lorougnon Guédé, BP 150 Daloa, Côte d’Ivoire
Most cocoa growing soils currently have a low level of chemical fertility. This does not make it possible to optimize the development of cocoa trees and ensure sustainable cocoa production. The objective of this study was to improve the fertility of soils under cocoa trees and cocoa production in Côte d’Ivoire. The study was conducted using a completely randomized Fisher block design, with three repetitions over two years. The organic fertilizer «Bokashi» was applied in a crown around the cocoa trees at doses of 0, 2, 4 and 6 kg per year, corresponding respectively to treatments T0 (control), T1, T2 and T3. Soil samples were taken before and after the addition of Bokashi to assess the initial and final fertility of the soil. The average numbers of wilted cherelles, healthy pods, rotten pods, weight of fresh beans and actual and potential yields of cocoa trees fertilized with Bokashi were evaluated and compared to those of the control treatment. The collected data were subjected to analysis of variance (ANOVA) using SAS 9.4 software. The results showed that the addition of Bokashi improves soil fertility and the productivity of cocoa trees. The application of Bokashi also made it possible to reduce the levels of certain elements in the soil such as aluminum, which in very high quantities can be toxic for most plants. The highest actual (1351.05 kg/ha) and potential (1846.8 kg/ha) yields having been obtained with the dose of 2 kg of Bokashi per year and per cocoa tree therefore constitute the optimal dose allowing improve the chemical fertility of the soil and the productivity of cocoa trees.