Learning from the rainforest: new approaches for West African cocoa

Ghana is the world’s largest producer of cocoa after Côte d’Ivoire. Around 50 to 60 percent of global cocoa production takes place in these West African countries. Switzerland is one of the biggest importers of cocoa from West Africa, with up to 70 per cent of its cocoa imports coming from the region. And for the Swiss chocolate industry, Ghana is now the most important source of cocoa. But the cocoa industry is currently in a state of crisis: Ghana’s smallholders are struggling with climate change and pest infestations, and many farms are affected by cocoa swollen shoot virus disease (CSSVD), which can destroy up to 50percent of a farm’s crop in the first two years after infection. Once infected, the tree invariably dies. There’s no cure for it; infected trees have to be uprooted and burned. At the same time, the number of hot days is increasing and the rainy seasons are shifting. The soil in many areas has been depleted by drought and intensive cocoa cultivation in monocultures.

Around 850,000 families in Ghana depend on cocoa farming, but most of them live in poverty. In desperation, many farmers end up selling their land to gold miners. This means cocoa-growing areas are being dug up and destroyed for ‘galamsey’, as illegal gold mining is known in the region, while rivers are being polluted with mercury and heavy metals. As a result, there have been major crop failures in Ghana in recent years– affecting the country’s most important agricultural export. The crisis in Ghana’s cocoa farming industry also poses a structural risk to the long-term stability of cocoa supply chains and thus to the Swiss chocolate industry. The supply of high-quality West African cocoa is becoming increasingly uncertain, cocoa prices are fluctuating more wildly and production costs are rising.

The potential of dynamic agroforestry

A Swiss–Ghanaian research team is currently investigating alternative farming methods to strengthen the cocoa industry. The SOR4D project ‘Dynamic cocoa agroforestry in action in Ghana’ focuses on the potential of dynamic agroforestry (DAF). Using a DAF approach, agronomists are attempting to replicate the cocoa plant’s natural habitat in the rainforests of South America. There, cocoa grows alongside other plants and trees of different heights, providing it with varying degrees of shade. Conceptually, DAF draws on the agroecological practices of indigenous groups and Swiss farmer Ernst Götsch, who developed the syntropic agroforestry model in Brazil. This approach involves optimising the use of available natural resources– especially light, water and nutrients– in a temporal and spatial sense. Targeted shade can be employed to control photosynthesis and the utilisation of biomass. Recent studies have shown that dynamic agroforestry has a positive impact on carbon sequestration, soil fertility, the water cycle, climate resilience and plant health. However, it also involves more manual labour and requires specialist knowledge.

‘We want to use our research to gain a better understanding of how dynamic agroforestry affects the environment and people,’ explains Johan Six, Professor of Sustainable Agroecosystems at ETH Zurich and co-leader of the SOR4D project. Based on these findings, solutions are being developed in collaboration with local partners in Ghana to strengthen the cocoa industry and provide farmers with dedicated support. A website and mobile app with learning resources, a forum and a marketplace have also been created in the course of the project to give farmers access to the knowledge and advice they need.

As part of the SOR4D project, the researchers are working with around 1,500 cocoa producers in several regions across Ghana. They are growing cocoa using dynamic agroforestry practices on a total of 800 hectares of land. Six and his team have been working with some of these farms for many years. One example is the Sankofa project, which is supported by a consortium that includes Swiss chocolate manufacturer HALBA. ‘Sankofa’ is a term used by the Akan people that means mutual respect, unity and learning from the past.

Agroforestry is still very much the exception in Ghana’s cocoa industry. According to the United Nations Environment Programme (UNEP), two million hectares of cocoa were grown in monocultures in 2022, which corresponds to around 87percent of total cultivation. ‘When it’s grown in monocultures, cocoa can quickly become susceptible to pests and drought and deplete the soil,’ explains Christian Andres, staff member for the Professorship for Sustainable Agroecosystems and coordinator of the project. ‘That’s why more pesticides and fertilisers have to be used.’

A better understanding of nutrient flows

Several Master’s students and one PhD student underwent training as part of the SOR4D project. Rita Balokah is studying at the Kwame Nkrumah University of Science and Technology (KNUST) in Accra and is writing her doctoral thesis on cocoa cultivation in dynamic agroforestry. She is particularly interested in the nutrient cycles of the cocoa plant and has collected 50 soil, 500 water and 3,000 gas samples over the past two years. Since neither synthetic pesticides nor chemical fertilisers are used in dynamic agroforestry, the plants must obtain their nutrients from organic material, such as cut branches and leaves. ‘We wanted to gain a better understanding of exactly where nutrients are lost; for example, whether they are washed out by rainwater or escape in the form of gas,’ Balokah explains.

The PhD student compared soil samples from conventional cocoa farms with those from farms that have been practising dynamic agroforestry for several years. The preliminary data shows that the soil’s microbial diversity is higher in dynamic agroforestry systems. ‘We can see that DAF has a positive effect on soil regeneration,’ says Balokah. One surprising finding, however, was that organic matter decomposes much faster on farms not using dynamic agroforestry. ‘We’d assumed the opposite would be true.’ Yet the researcher also found an explanation for this: In degraded soils, organic matter is broken down very quickly by termites. In the more diverse, vibrant soils, however, this takes longer and nutrients are released gradually, which ultimately benefits the cocoa trees: their roots tend to be healthier and more densely populated by fungi.

Balokah also measured the amounts of carbon dioxide, methane and nitrous oxide emitted by the soil – all of which are greenhouse gases. To do so, she set up gas-collection chambers across several fields over a period of two years. She collected more than 3,000 gas samples and, like the soil samples, spent several months analysing them at ETH Zurich. As the PhD student explains, collecting the samples in Ghana was no mean feat. Above all, she had difficulty finding assistants to stand in for her during her stays in Switzerland. ‘It was a real joint effort in the end,’ says Balokah. ‘If we hadn’t had such a good network and our local project partners, we wouldn’t have been able to collect these measurements.’

Bananas, coffee and palm oil as additional crops

The research group also investigated whether there are differences in crop yields between farms that practise dynamic agroforestry and those that do not. There are no conclusive results on this yet, according to Johan Six. However, it is important to bear in mind that dynamic agroforestry involves harvesting not only cocoa but also a range of other crops such as bananas, coffee and palm oil. ‘We didn’t measure these yields as part of the project,’ says Six. Previous studies have also shown that the productivity of cocoa trees is initially higher when synthetic fertilisers are used and when the trees are exposed to full sunlight. This productivity then declines, while yields in agroforestry tend to increase over time.

Issues related to farmers’ health are also part of the SOR4D project. Highly toxic insecticides and herbicides are still being used in Ghana’s agricultural sector, including some that have been banned in the EU and Switzerland, such as the deadly paraquat. Pesticides are often applied manually using a backpack sprayer; farmers tend not to use protective equipment while doing so, and this can have severe consequences for their health. As part of her Master’s thesis, ETH environmental scientist Delia Hürlimann wanted to gain a better understanding of how sustainable cocoa farming affects human and animal health. No synthetic pesticides are used in dynamic agroforestry. Hürlimann conducted interviews with 22 farmers and evaluated over 470 questionnaires. According to her study, cocoa farmers who use pesticides reported skin irritation, eye irritation and back pain much more frequently.

The researchers were also interested in the respondents’ mental health. The picture is still somewhat mixed, says Six. ‘However, we can see that farmers using agroforestry tend to speak more positively about their cocoa farms; not only as a place of hard physical labour, but also as a place of retreat and relaxation.’ How healthy, committed and motivated farmers are is often directly reflected in the farm’s productivity, adds Six. ‘It’s an aspect that is often overlooked.’

More labour-intensive, but more resilient

Johan Six emphasises that the cocoa industry’s transformation towards more dynamic agroforestry is not possible without government support. Dynamic agroforestry is more labour-intensive in terms of caring for the trees, as farmers do not use chemical pesticides or fertilisers. They also need to be given proper training, as most of them lack the knowledge required to make the switch to dynamic agroforestry.

That is why the researchers are working closely with the Sankofa project, which maintains good contacts with political decision-makers in Ghana, in particular representatives of the Ghana Cocoa Board (Cocobod). This government body conducts its own agronomic research, monitors the cocoa supply chain and sets selling prices. In recent years, contact with Cocobod has been stepped up through the Swiss Platform for Sustainable Cocoa (SWISSCO), the Swiss industry platform whose members include HALBA, Lindt, Nestlé, Migros, Coop and Syngenta, with agroforestry being promoted as a response to current challenges in cocoa farming.

‘If Cocobod were to support dynamic agroforestry, the approach could be scaled up nationally,’ says Christian Andres. He believes that this may well be a realistic development, not least because research outside the SOR4D project shows that dynamic agroforestry can also be used as a strategy to contain CSSVD. ‘Shaded cocoa trees in agroforestry are less stressed and therefore more resistant to the virus,’ Andres explains. This is an argument that could go a long way to convincing Cocobod.

Change can happen, but the price has to be right

PhD student Rita Balokah has observed positive developments in terms of sustainable transformation among the farmers she works with on a regular basis. ‘Some who had previously grown cocoa in monocultures began to convert their farms themselves during the project after seeing how beautifully cocoa grows in agroforestry systems – without the use of chemical products.’ However, Balokah is convinced that, for dynamic agroforestry to gain more traction in Ghana, the economic framework also needs to change. ‘Chocolate manufacturers earn billions from cocoa, while most farmers in Ghana are struggling to survive.’ Unless the price of cocoa rises and gives producers a fair income, there will be no scope for change. ‘This is the only way the cocoa industry in Ghana is going to survive in the long term.’