Cacao-fruit tree intercropping effects on cocoa yield, plant vigour and light interception in Cte d'Ivoire

A major challenge for cocoa producers in Cte d'Ivoire is to seek alternative shade trees or crop associations to adapt their planting devices and techniques to the shortage of forests. The recent tendency developed by farmers is to plant simplified orchards combining cacao and fruit trees. An on-farm trial was set up in a 5-year-old cocoa farm to compare a cacao monocrop planted at densities of 1,115 trees ha(-1) with cacao intercropped with orange or avocado trees, both at 44 trees ha(-1). Observations were done on incident light received by the cacao, vigour, growth and cocoa yields. On average, the cacaos received 100 % light in the monocrop, 89.6 % under orange trees and 80.6 % of incident light under avocado trees. They yielded 64.0 pods tree(-1) year(-1) in the monocrop (equivalent to 2.54 kg dry cocoa beans tree(-1)), 30.3 pods tree(-1) when combined with orange trees and 28.3 pods tree(-1) with avocado trees. The two combinations allowed cocoa yields equivalent to those observed in the region (0.58 kg dry cocoa beans tree(-1)). Vigour and yield were very highly correlated with the incident light received. Both the yield and the incident light are a logistic function of the planting distance from the shade tree. The inflexion point of the logistic functions corresponds to the minimum planting distance between the cacao and the intercropped fruit trees. On this basis, we suggest that the cacaos should not be planted closer than 6.50 +/- A 0.2 m to the orange or avocado trees.