The Impact of traditional cocoa-based agroforestry systems on chemical soil fertility in southwest of Côte d'Ivoire

The sustainability of cocoa farming is a major concern for Côte d'Ivoire. Extensive and "full sun" cropping systems need to be reviewed. Against this backdrop, a study was carried out in the south-west of the country (Soubré and Méagui), a major production zone, with the aim of assessing the impact of traditional agroforestry systems on soil fertility.
Twenty-seven cocoa farms in the three sectors were visited. To assess the impact of cocoa-based agroforestry systems on soil chemical parameters, four criteria guided the choice of plots. These were mid-slope plots, 25 to 35 years old, unfertilized and denser in associated trees. Soil samples were taken from the 0-20 cm horizon. Organic carbon, total nitrogen, assimilable phosphorus, exchangeable bases (Ca, Mg, K and Na), cation exchange capacity and saturation rate were measured.
The results show that traditional cocoa-based agroforestry systems have not impoverished the soil. In fact, chemical fertility in these plots respects the needs of cocoa trees. However, the study did not show an increase in soil organic matter due to the fall of leaves from associated trees.
These results will enable the use of traditional agroforestry systems without fear of soil impoverishment due to any competition between cocoa trees and associated trees.