Remediation of Cocoa Soils in Ghana as a Route to more Sustainable Cocoa Production
Lead Research Organisation:
University of Reading
Department Name: Sch of Agriculture Policy and Dev
Abstract
Summary
Cocoa is grown extensively in West Africa, producing 75% of world production. Ghana is the second most important cocoa producing country, where cocoa production provides a livelihood for an estimated 800,000 smallholder farmers. One of the main challenges facing the cocoa sector in West Africa is long-term soil deterioration on cocoa farms because of the depletion of soil nutrients caused by poor farming practices. This has resulted in a shifting cultivation pattern, and migration of cocoa farmers into virgin forest areas which is clearly unsustainable. Measures to improve soil health would improve both on-farm yields and thus the livelihoods of smallholder cocoa farmers. Previous collaborative research between the University of Reading and the Cocoa Research Institute of Ghana (CRIG) has demonstrated that many cocoa farms are deficient in key soil nutrients but also that inorganic fertilisers are unaffordable for many farmers. Against this background, this project seeks to explore routes for soil improvement on cocoa farms through utilisation of on-farm waste products, thereby contributing to more sustainable crop production and thus maintenance of livelihoods of smallholder cocoa farmers.
The project will explore the use of composted and pyrolysed (burning organic materials in the absence of oxygen to produce "biochar") farm waste as soil amendments to improve soil fertility and health on cocoa smallholdings. Experiments will be conducted on a network of cocoa farms, established in a previous project, to ascertain the impact of composted farm waste and biochar on the performance of established cocoa trees. This will be evaluated through changes in yield and assessments of plant health by measuring the presence of pests and diseases. Shade trials at CRIG will also be utilised to ascertain the impact of maintained overhead shade trees on soil micro and macro fauna. Complementary experiments will also be conducted in the greenhouses of CRIG on seedlings in pots to ascertain the impacts of different soil amendments on the performance of juvenile cocoa. These experiments will also assess whether the performance of plants subjected to drought is improved by cultivation on soils ameliorated with different composts. Furthermore, the greenhouse experiments will consider whether plants grown in soils ameliorated with different composts are less susceptible to attack by insect pests and by diseases. Additional pot experiments will be conducted at the University of Reading in which cocoa seedlings grown in different soil amendments will be subjected to different temperature regimes within growth cabinets.
Analyses will be conducted on the properties of soils amended with composts. These will assess the extent to which cation exchange capacity and availability of nutrients are improved through composting and biochar production. The microbiology and macrofauna of compost amended soils will be compared with controls as a critical factor that impacts on nutrient availability to the crop.
The cost: benefit ratio of using composts and biochar will be explored and communicated to farmers through farmer field schools in the latter stages of the project. These events will be conducted on farms on which the trials were conducted and composting methods/ pyrolysis methods will be demonstrated to farmers.
A summary of our findings will be presented at an end of project workshop which will be held in Ghana and attended by key stakeholders in the cocoa production chain. Furthermore, we will produce a manual and video that will be used as tools by extension agents to take the technologies developed out to larger numbers of farmers
Cocoa is grown extensively in West Africa, producing 75% of world production. Ghana is the second most important cocoa producing country, where cocoa production provides a livelihood for an estimated 800,000 smallholder farmers. One of the main challenges facing the cocoa sector in West Africa is long-term soil deterioration on cocoa farms because of the depletion of soil nutrients caused by poor farming practices. This has resulted in a shifting cultivation pattern, and migration of cocoa farmers into virgin forest areas which is clearly unsustainable. Measures to improve soil health would improve both on-farm yields and thus the livelihoods of smallholder cocoa farmers. Previous collaborative research between the University of Reading and the Cocoa Research Institute of Ghana (CRIG) has demonstrated that many cocoa farms are deficient in key soil nutrients but also that inorganic fertilisers are unaffordable for many farmers. Against this background, this project seeks to explore routes for soil improvement on cocoa farms through utilisation of on-farm waste products, thereby contributing to more sustainable crop production and thus maintenance of livelihoods of smallholder cocoa farmers.
The project will explore the use of composted and pyrolysed (burning organic materials in the absence of oxygen to produce "biochar") farm waste as soil amendments to improve soil fertility and health on cocoa smallholdings. Experiments will be conducted on a network of cocoa farms, established in a previous project, to ascertain the impact of composted farm waste and biochar on the performance of established cocoa trees. This will be evaluated through changes in yield and assessments of plant health by measuring the presence of pests and diseases. Shade trials at CRIG will also be utilised to ascertain the impact of maintained overhead shade trees on soil micro and macro fauna. Complementary experiments will also be conducted in the greenhouses of CRIG on seedlings in pots to ascertain the impacts of different soil amendments on the performance of juvenile cocoa. These experiments will also assess whether the performance of plants subjected to drought is improved by cultivation on soils ameliorated with different composts. Furthermore, the greenhouse experiments will consider whether plants grown in soils ameliorated with different composts are less susceptible to attack by insect pests and by diseases. Additional pot experiments will be conducted at the University of Reading in which cocoa seedlings grown in different soil amendments will be subjected to different temperature regimes within growth cabinets.
Analyses will be conducted on the properties of soils amended with composts. These will assess the extent to which cation exchange capacity and availability of nutrients are improved through composting and biochar production. The microbiology and macrofauna of compost amended soils will be compared with controls as a critical factor that impacts on nutrient availability to the crop.
The cost: benefit ratio of using composts and biochar will be explored and communicated to farmers through farmer field schools in the latter stages of the project. These events will be conducted on farms on which the trials were conducted and composting methods/ pyrolysis methods will be demonstrated to farmers.
A summary of our findings will be presented at an end of project workshop which will be held in Ghana and attended by key stakeholders in the cocoa production chain. Furthermore, we will produce a manual and video that will be used as tools by extension agents to take the technologies developed out to larger numbers of farmers
Technical Summary
Degradation of soils on cocoa farms is a major factor facing the cocoa sector in West Africa. The project will consider how farm wastes (pod husks and prunings from cocoa and shade trees) can be utilised as soil amendments through composting and pyrolysis. Whilst studies have been conducted on ashed cocoa pods, there are knowledge gaps in terms of the efficacy of co-composted pod husks and pyrolyzed pod husks/ prunings as soil amendments.
To address these issues, we will:
i. examine the chemical and physical of co-composted and pyrolyzed pod husks/ pruning compared with raw materials with particular attention to the chemical form of P in wastes, composts and biochars and to changes in the C:N ratio.
ii. examine whether Phytophthora spores (causing Blackpod disease) are eliminated through the composting process.
iii. utilise the composted and pyrolyzed materials in on farm trials. The impact of these soil amendments on the performance of cocoa trees will be evaluated in terms of growth and yields as well as on the presence of pests and diseases in the field.
iv. compliment field trials with detailed pots trials which will examine the performance of seedlings grown with different composts and subjected to abiotic (water deficit and high temperature) and biotic stresses (presence and absence of pests and diseases).
v. assess changes in nutrient availability in the amended soils from the field and pot trials through examination of both the physio-chemical and biological properties of the soils.
vi. explore changes in soil microbiology and macro-fauna in the amended soils and also within shaded versus non-shaded cocoa.
In addition to these experimental approaches, a cost: benefit analysis will be conducted on the use of composted and pyrolyzed materials on cocoa farms. Farmers will be engaged in the project through on-farm trials and the results disseminated through farmer field schools, a manual and video and an end of project workshop.
To address these issues, we will:
i. examine the chemical and physical of co-composted and pyrolyzed pod husks/ pruning compared with raw materials with particular attention to the chemical form of P in wastes, composts and biochars and to changes in the C:N ratio.
ii. examine whether Phytophthora spores (causing Blackpod disease) are eliminated through the composting process.
iii. utilise the composted and pyrolyzed materials in on farm trials. The impact of these soil amendments on the performance of cocoa trees will be evaluated in terms of growth and yields as well as on the presence of pests and diseases in the field.
iv. compliment field trials with detailed pots trials which will examine the performance of seedlings grown with different composts and subjected to abiotic (water deficit and high temperature) and biotic stresses (presence and absence of pests and diseases).
v. assess changes in nutrient availability in the amended soils from the field and pot trials through examination of both the physio-chemical and biological properties of the soils.
vi. explore changes in soil microbiology and macro-fauna in the amended soils and also within shaded versus non-shaded cocoa.
In addition to these experimental approaches, a cost: benefit analysis will be conducted on the use of composted and pyrolyzed materials on cocoa farms. Farmers will be engaged in the project through on-farm trials and the results disseminated through farmer field schools, a manual and video and an end of project workshop.
Planned Impact
Impact Statement
Ghana is the world's second largest producer of cocoa and around 800,000 smallholder farmers are engaged in cocoa farming at a subsistence level. At a national level, cocoa exports account for a considerable proportion of Ghana's GDP (estimate for 2004 to 2008 is 39% of GDP)[1] and cocoa is the third biggest export commodity and foreign exchange earner[2]. However, the sustainability of cocoa production is a major concern.
Cocoa farms typically have a productive life span of between 20 and 30 years, during which the soils become depleted of key nutrients and yields fall. As a consequence, farmers will often move to new land, much of which has, to date, been virgin forest. This practice is set to become prohibited with the Ghanaian government, together with leading chocolate and cocoa companies, agreeing a framework to end deforestation associated with cocoa production as part of the 2017 UN Climate Change Conference (COP23)[3]. At the same time, the Ghanaian Government, and the cocoa sector more widely, have made clear in the framework their commitment to growing more cocoa on less land. The methods developed to improve soil health in this proposal will be expected to increase yields and maintain more sustainable productivity on smallholdings. This, in turn, will have an impact on the livelihoods of cocoa farmers and on the national economy.
The primary beneficiaries of this research will be cocoa farmers who are predominantly smallholders and depend on cash from the sale of cocoa to support their livelihoods and education of their children. The application of low cost, organic soil amendments will be expected to improve and maintain crop yields from existing lands with a concurrent benefit to farmer livelihoods. The transfer of technologies that enable farmers to produce compost and biochar from farm wastes will enable farmers to become less dependent on fertilisers that may vary in price according to levels of subsidy at any particular time.
Secondary beneficiaries of the research will be local entrepreneurs who may adopt the composting and pyrolysing techniques identified in the project to produce soil amendments to sell commercially. Furthermore, there is the potential opportunity for farmers to diversify their incomes through the production of soils amendments.
Providing farmers with technologies to maintain soil health will enable sustainable cocoa production, maintaining the long-term viability of cocoa farms and thus removing the driver for shifting cultivation. This will help the Government and cocoa sector to meet their commitment to grow more cocoa on less land, and not at the expense of tropical forests that represents major stocks of carbon.
References
[1] Ofori-Bah et al. Ecological economics 70, 1508-1518 (2011)
[2] http://www.worldstopexports.com/ghanas-top-10-exports/
[3] http://www.worldcocoafoundation.org/cocoa-forests-initiative/
Ghana is the world's second largest producer of cocoa and around 800,000 smallholder farmers are engaged in cocoa farming at a subsistence level. At a national level, cocoa exports account for a considerable proportion of Ghana's GDP (estimate for 2004 to 2008 is 39% of GDP)[1] and cocoa is the third biggest export commodity and foreign exchange earner[2]. However, the sustainability of cocoa production is a major concern.
Cocoa farms typically have a productive life span of between 20 and 30 years, during which the soils become depleted of key nutrients and yields fall. As a consequence, farmers will often move to new land, much of which has, to date, been virgin forest. This practice is set to become prohibited with the Ghanaian government, together with leading chocolate and cocoa companies, agreeing a framework to end deforestation associated with cocoa production as part of the 2017 UN Climate Change Conference (COP23)[3]. At the same time, the Ghanaian Government, and the cocoa sector more widely, have made clear in the framework their commitment to growing more cocoa on less land. The methods developed to improve soil health in this proposal will be expected to increase yields and maintain more sustainable productivity on smallholdings. This, in turn, will have an impact on the livelihoods of cocoa farmers and on the national economy.
The primary beneficiaries of this research will be cocoa farmers who are predominantly smallholders and depend on cash from the sale of cocoa to support their livelihoods and education of their children. The application of low cost, organic soil amendments will be expected to improve and maintain crop yields from existing lands with a concurrent benefit to farmer livelihoods. The transfer of technologies that enable farmers to produce compost and biochar from farm wastes will enable farmers to become less dependent on fertilisers that may vary in price according to levels of subsidy at any particular time.
Secondary beneficiaries of the research will be local entrepreneurs who may adopt the composting and pyrolysing techniques identified in the project to produce soil amendments to sell commercially. Furthermore, there is the potential opportunity for farmers to diversify their incomes through the production of soils amendments.
Providing farmers with technologies to maintain soil health will enable sustainable cocoa production, maintaining the long-term viability of cocoa farms and thus removing the driver for shifting cultivation. This will help the Government and cocoa sector to meet their commitment to grow more cocoa on less land, and not at the expense of tropical forests that represents major stocks of carbon.
References
[1] Ofori-Bah et al. Ecological economics 70, 1508-1518 (2011)
[2] http://www.worldstopexports.com/ghanas-top-10-exports/
[3] http://www.worldcocoafoundation.org/cocoa-forests-initiative/
| Description | We have assessed the effects of shade tree species and spacing on soil characteristics in a long-term (>5 years) cocoa agroforestry field experiment in Ghana. Preliminary results show that, overall, shade tree species and spacing had limited effects on soil organic matter (SOM) content and soil fertility. However, SOM content was positively correlated with several soil fertility parameters. This not only indicates that SOM is vital for soil fertility in this soil but also suggests that even in cocoa agroforestry systems there is need to increase SOM through additional measures to improve multiple soil fertility parameters and cocoa productivity. The latter is the subject of our ongoing investigations, for example in on-farm trials with/without compost and biochar soil amendments produced using on-farm waste. A survey was conducted of 150 cocoa farmers to assess their knowledge and willingness to use organic soil amendments (compost and biochar). A majority of farmers (67%) perceived that there was a decline in soil fertility on their farms. Whilst just under half of the farmers interviewed were aware of compost, few had knowledge of how to prepare it themselves. Nevertheless, most farmers (96%) were willing to learn how to make compost. In contrast, very few farmers were aware of biochar but again most of them (96%) were willing to learn how to make it. |
| Exploitation Route | Farmers participating in the research and those in the surrounding communities have been trained in the making of compost and biochar. The outcomes of the research have been presented in a webinar in which a range of stakeholders were present. Further workshops took place in February/March 2023 in which practical knowledge of compost and biochar production was disseminated to farmers and extension agents. |
| Sectors | Agriculture, Food and Drink,Environment |
| URL | https://research.reading.ac.uk/cocoa/soil-amendments-project/ |
| Description | Farmers associated with this project have an improved understanding of using waste resources on-farm to produce compost and biochar. |
| First Year Of Impact | 2020 |
| Sector | Agriculture, Food and Drink |
| Impact Types | Cultural |
| Description | Adoption of on-farm composting and biochar production at a regional level |
| Geographic Reach | Local/Municipal/Regional |
| Policy Influence Type | Contribution to new or improved professional practice |
| Impact | There has been a change in on-farm practice in terms of increased use of organic amendments catalysed by the increased cost of inorganic fertilisers. |
| Description | GCRF AgriFood Africa Innovation Awards Round 3 |
| Amount | £30,000 (GBP) |
| Organisation | Innovate UK |
| Sector | Public |
| Country | United Kingdom |
| Start | 10/2022 |
| End | 03/2023 |
| Description | GCRF Agritech Catalyst Seeding Award (GCRF-SA-2020-Reading). Sub-project: Developing a digital platform for cocoa production in Ghana |
| Amount | £142,000 (GBP) |
| Funding ID | GCRF-SA-2020-Reading |
| Organisation | United Kingdom Research and Innovation |
| Department | Global Challenges Research Fund |
| Sector | Public |
| Country | United Kingdom |
| Start | 03/2020 |
| End | 09/2021 |
| Description | GCRF and Newton Consolidation Accounts University of Reading |
| Amount | £23,750 (GBP) |
| Funding ID | EP/X527816/1 |
| Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
| Sector | Public |
| Country | United Kingdom |
| Start | 10/2022 |
| End | 03/2023 |
| Description | Soil amendments in cocoa |
| Amount | £66,510 (GBP) |
| Organisation | Barry Callebaut |
| Sector | Private |
| Country | Belgium |
| Start | 01/2020 |
| End | 06/2021 |
| Title | Digital data capture |
| Description | A digital data collection system was devised for use in the field. The system uses scannable bar codes/ QR codes which are fixed to trees from which data is collected. Android mobile phones are then used to scan the codes and enter data which are then subsequently uploaded to an on-line platform. |
| Type Of Material | Technology assay or reagent |
| Year Produced | 2022 |
| Provided To Others? | Yes |
| Impact | The method improves the efficiency of large-scale data collection, negating the need to subsequently transcribe data. It also reduced errors associated with data collection. |
| Description | Barry Callibaut |
| Organisation | Barry Callebaut |
| Country | Belgium |
| Sector | Private |
| PI Contribution | Discussions on soil amendments and experimental approaches |
| Collaborator Contribution | Funding and provision of materials |
| Impact | Collaboration at early stage |
| Start Year | 2020 |
| Description | Cocoa Research Institute of Ghana (CRIG) |
| Organisation | Cocoa Research Institute of Ghana |
| Country | Ghana |
| Sector | Academic/University |
| PI Contribution | Members of the research team have visited CRIG twice since the project inception to discuss protocols for the project and to visit project field sites. We are in regular contact with CRIG staff through monthly video calls and e-mail exchanges. We have provided specific training in the use of nanopore technology to a member of staff from CRIG during a project visit to the University of Reading. |
| Collaborator Contribution | CRIG are responsible for the following activities with the project:- - Selection of farms on which field trials are taking place - Application of soil amendment treatments on project farms - Collecting soil samples and analysis for macrofaunal - Sending of samples to project partners (KNUST and University of Reading) - Collection of data from on-farm trials - Demonstrating composting and biochar production to farmers - Setting up greenhouse experiments and collection of data from these experiments |
| Impact | The collaboration is multi-disciplinary and involves soil science, crop production and crop physiology. The principal outcomes to date has been exchange of approaches to research protocols and capacity building through training of staff in particular techniques. |
| Start Year | 2019 |
| Description | Kwame Nkrumah University of Science and Technology |
| Organisation | Kwame Nkrumah University of Science and Technology (KNUST) |
| Country | Ghana |
| Sector | Academic/University |
| PI Contribution | Members of the research team have visited KNUST twice since the project inception to discuss protocols for the project and to visit project field sites. We are in regular contact with CRIG staff through monthly video calls and e-mail exchanges. We have provided specific training in the use of nanopore technology to a member of staff from KNUST during a project visit to the University of Reading. |
| Collaborator Contribution | KNUST are responsible for the following activities:- - Developing techniques for composting and biochar production from cocoa pods - Production of compost and biochar for on-farm trials - Training of farmers in the production of biochar and compost - Analysis of samples from field sites - Conducting a social science survey of farmers participating in the project and other farmers in the local communities |
| Impact | The collaboration is multi-disciplinary involving aspects of soil science, crop science and physiology. The main outcomes to date have been through exchange of knowledge on research approaches and capacity building through staff training in laboratory techniques. |
| Start Year | 2019 |
| Description | Farmer workshop 2021 |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Professional Practitioners |
| Results and Impact | Field based workshops carried out over two days training farmers how to make biochar and fertilizers from farm waste. |
| Year(s) Of Engagement Activity | 2021 |
| Description | Farmer workshops 2023 |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Professional Practitioners |
| Results and Impact | A number of field-based workshops took place during February and March 2023 demonstrating how to produce compost and biochar from farm wastes to farmers and extension agents. |
| Year(s) Of Engagement Activity | 2023 |
| Description | Farmers engagement |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Professional Practitioners |
| Results and Impact | Training of farmers in cocoa-growing communities in the production of compost and biochar. |
| Year(s) Of Engagement Activity | 2020 |