African researchers and growers are banking on sustainable cocoa

Once the soils in a given area are degraded, farmers move on to the last remaining forest areas. In the end, for want of accessible forest resources, cocoa production in West and Central Africa is likely to fall. The problem is that with some 4.5 million hectares of cocoa, the sector provides a living for huge numbers of rural inhabitants in Africa, for instance six million people in Ghana.

It is also one of the main sources of foreign currency: in Ivory Coast, cocoa accounts for some 30% of the country's total exports. Unless a viable agronomic alternative can rapidly be transferred to smallholders in order to sedentarize cocoa production, the economic and social situation in these cocoa-growing zones may eventually become critical.

In response to this agronomic and socioeconomic challenge, CIRAD researchers and their partners opted to set up an African research network. The network falls under the aegis of the Cocoa Producers Alliance (COPAL) and the West and Central African Council for Agricultural Research and Development (CORAF/WECARD), and comprises 35 researchers from 32 research and development organizations in the leading five cocoa-producing countries in Africa: Ivory Coast, Ghana, Togo, Nigeria and Cameroon. The structure, which was initiated under a project on competitive and sustainable cocoa in Africa (SCCS) enabled the launch of nine research operations between 2002 and 2006, with the active involvement of numerous producers in the five countries.

The researchers, technicians and growers involved have primarily worked along four lines: improved cropping systems, participative breeding of cultivars either tolerant of or resistant to the diseases that affect cocoa, protection against pests and diseases, and soil fertilization.

Improved methods that cocoa producers can easily take on board

As regards improved cocoa cropping, researchers have drawn up a typology of the different cropping systems and characterized in detail the agroeconomic conditions for growing cocoa and the environmental conditions in the areas concerned. In particular, the idea was to adapt crop management sequences to the socioeconomic conditions in which growers work. The project subsequently enabled the development of methods for rehabilitating unproductive cocoa plantings that were both more effective than the existing methods and easy for producers to adopt: pruning and budding using improved material, redensification, and phytosanitary protection. The results have also highlighted the merits of growing cocoa under shade – in particular, it conserves the biodiversity and climatic plasticity of the cropping system – and of intercropping it with other crops (fruit, market garden or cash crops) to diversify the growers' sources of income.

Resisting devastating diseases is crucial in ensuring sustainable cocoa growing in Africa. Two diseases are of particular concern: black pod rot and cocoa swollen shoot virus (CSSV). To tackle the problem, researchers have opted to work on potentially resistant cultivars. In Togo, they have bred a certain number of hybrids whose tolerance of, if not resistance to, these diseases has yet to be confirmed under field conditions.

Diseases are not the only obstacle. Cocoa trees are also subject to attacks from numerous sucking insects. One, known as a mirid or capsid, attacks the young branches, which then become necrotic, and the pods. There are control methods, but they are too expensive for growers. One solution is to cut the cost of treatment. To this end, the trees have to be treated at just the right stage in the insect's development. This makes treatment more effective and reduces the environmental impact. An early warning system is currently being tested in Cameroon.

The last task is the maintenance and rational restitution of soil fertility. Cocoa growing calls for large quantities of soil minerals, but without fertilizer applications, the soils are exhausted within twenty years or so. In an attempt to manage soil fertility more efficiently, researchers have tested a decision support tool for rational fertilization that can rapidly devise formulas that are suitable from both an economic and an ecological point of view.

* 2005 figures