Crop ecological aspects and modelling of cocoa production: understanding effects of pruning and shading

Millions of small holder farmers in West Africa produce 73% of the global cocoa production. The majority of cocoa is produced in agroforestry systems with shade trees and low input of nutrients. In addition, cocoa stands are often poorly managed, with little attention to maintenance and pruning. As a result, realized yields are far those that can be potentially reached in the region.

Pruning improves vegetation growth and production in tree crops as it optimizes the balance of vegetative and reproductive growth and increases the efficacy of fertilization and pest control. However, current pruning practices in cocoa are minimal and recommended practices lack scientific support. Pruning has deep effects on plant functioning and assimilate partitioning, which are expected to strongly interact with the level of shading. These effects crucially determine yield but have not been quantified so far.

The project objective is to understand and quantify cocoa response to pruning in relation to shading and to design optimal pruning practices tailored for the specific agronomical condition of West Africa.

A great number of physiological processes are simultaneously affected by pruning and shading. Many of these processes are influenced and influence the spatial structure of the cocoa plant. Therefore, a functional structural modelling approach, in combination with field trials, is applied here.

Pruning experiments will be conducted on juvenile and adult plants to quantify local responses in resources allocation, and to gather plant architecture and development data for model calibration. An FSP model of the cocoa plant will be developed to explicitly simulate the effects of pruning and shading on plant architecture and yield. Scenarios studies will done to determine optimal practises under different shade and for a range of temperature and irradiance conditions.