A study conducted by the PUR Lab, in partnership with the Université Libre de Bruxelles and the Universidad Agraria de la Selva in Peru, shows that agroforestry cocoa systems can increase quality by 86% and yields by 62%, compared to full-sun systems.
How agroforestry can influence cacao yields?
Switching from full-sun systems to agroforestry is quite a big challenge for farmers. In order to increase or maintain yields and harvest quality, the system must be designed cautiously considering several parameters, trees’ density included. Shade trees modify the micro-climate for the crop, access to light, soil’s nutrients and water. They can of course influence either positively or negatively the harvest: too many trees can favor diseases due to fungus development (humidity) and may also induce competition for light, water and nutrients.
Key facts and curiosities
In Ivory Coast, one of the most important cocoa producing countries – the project Vision for Change (V4C) lead by ICRAF and MARS Chocolate-, is aimed at strengthening smallholders cocoa farming by adding trees to their parcels. Five years after the beginning of the project, a study was undertaken by researchers from the University of California–Davis (Gyau et al., 2015) amongst 400 farmers. Half of them declared that they would plant more trees in the future, saying that their primary motivation was to increase cocoa yields and to decrease pest and disease pressure.
“In sharp contrast with the previous four decades when full-sun cocoa was the recommended standard, extension services are now recommending partially shaded cocoa for better yields and sustainability […]” Christophe Koumé, ICRAF scientist, V4C Project director.
Historically, cacao was cultivated by indigenous people from central America, mainly by the Aztec and the Mayas. Its scientific name Theobroma cacao stands for “the Gods delicacy”, as its cultivation was intimately linked to spiritual rituals and its seeds were even used as local currency. Finally, the plant’s natural habitat is under the shade of the impressive tropical forests trees from Amazonia.
PUR Lab, in partnership with two universities studied the impact of such a practice. The objective was to assess the optimal shade tree density to ensure both cocoa yields and quality for the farmers involved in the reforestation project. We have been studying farmers plots with 4 different shade trees densities, from high density (440 trees/ha) to full sun (0 trees/ha), during 4 harvests.
We found out that the rate of healthy pods is optimal in low density agroforestry systems (50 trees/ha), being 86% higher when compared to full sun systems. And more, the same comparison showed that yields were 62% higher in low density systems than in full-sun systems.
PUR Lab will then study new densities (from 0 to 200 trees/ha) and species of tree in order to more precisely assess the impact of agroforestry on yields.
Quality is assessed by measuring the percentage of healthy cocoa pods on trees. Yields are assessed by weighing the wet cocoa beans harvested (beans with mucilaginous pulp, called baba de cacao in South America). We selected various plots (depending on tree density) and delimitated areas containing 180 cocoa trees (approx. 1000 m² surface). Then, the cocoa fruits on the trees were counted and classified: healthy, aborted, damaged by fungus (moniliasis) or other pests, or rotted. Finally, wet cocoa beans were weighed during 4 harvests (February, March, July and August).