Where do the nutrients go? Investigating nutrient partitioning in cocoa trees


While demand of the important global commodity cocoa is increasing, productivity in many regions is stagnating and even declining. As worries about supply deficits rise, important players in the cocoa sector are setting up programmes to help smallholder farmers, who account for almost all cocoa production, to increase their yields. Among the agronomic issues addressed is mineral nutrition. Like any plant, cocoa needs nutrients to grow. After years of cocoa production, soils in many of the small cocoa farms are depleted of nutrients. Fertilisers may need to be applied to sustain and/or increase production. However, scientific knowledge to derive appropriate fertiliser recommendations is lacking. Required nutrient uptake for adequate growth and production is unknown. To achieve a high productivity, nutrients are needed not only for the production of the cocoa beans, but also for the vegetative growth, consisting of stems and branches (the woody parts of the tree), leaves and roots. Little is known about the amounts of nutrients present in these vegetative components. For this reason, we want to measure the biomass and nutrient content of the vegetative components of the cocoa tree. Your work will involve:

-      Exploring methods for destructive harvesting of trees and determining weight and nutrient content of tree components (literature)

-      Applying the appropriate method to cocoa trees in the field (although cocoa trees are relatively small, this may include physically demanding activities)

-      Analyse the results

The project

This topic is part of a PhD research which aims to increase the knowledge on mineral nutrition of cocoa, to improve the scientific basis of farm level fertiliser recommendations. An extensive literature review has resulted in the identification of a number of fundamental knowledge gaps regarding the mineral nutrition of cocoa. Lack of understanding of nutrient partitioning in the cocoa trees is one of them.


Depending on research location


Willingness and ability to conduct field work in Ghana, Ivory Coast or Ecuador (to be confirmed) consisting of destructive harvesting of trees, weighing tree components and preparing samples for nutrient analysis; affinity with quantitative analysis.

Period and Location

Any time; Wageningen and Ghana/Ivory Coast/Ecuador (to be confirmed)


Maja Slingerland                                0317 − 483512                        maja.slingerland@wur.nl

Jiska van Vliet                                                                                    jiska.vanvliet@wur.nl