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.

The high price of chemical inputs has led producers to use other sources of fertilizer such as chicken manure. However, the direct and compost-free application of these wastes as practiced by producers is a potential source of soil acidification and environmental contamination that cannot adequately restore soil fertility. The objective of the study was to evaluate the effects of composting times on the chemical fertility of the composts produced. The study was carried out at the Jean Lorougnon Guédé University in the Tazibouo district of Daloa, in the centre-west of Côte d'Ivoire. Twelve (12) piles of chicken manure were made up of 3 piles per treatment corresponding to the different composting times (T14, T21, T28, T35 days). Four treatments rated T14, T21, T28 and T35 corresponding to 14, 21, 28 and 35 days of composting of the feces were compared to a control treatment T0 (composted chicken feces). The study found that composting chicken manure has positive effects on its chemical fertility by improving the levels of most of the physical and chemical parameters of the composts produced. As a result, composting has reduced concentrations of trace metal elements, such as iron and zinc, in composted chicken droppings, which at high soil levels become toxic to plants. Composting the manure for 14 days by improving the fertility of the composts produced can therefore be recommended to growers for a better chemical quality of the compost produced.